School of Neuroscience for Thai Youth

Action potential is an all-or-nothing phenomenon and represents the basic electrical signal of the neuron. It is initiated at the initial segment of the axon hillock of the neuron and is propagated down the axon to the presynaptic terminals. It is typically in the order of 100 mV in amplitude

Active touch involves the corticospinal tracts and somatosensory system in the perception of shapes and textures by the manipulation of objects in the hand

Active zones are found in the presynaptic nerve terminal and are the sites where calcium enters the nerve terminal and the presynaptic vesicles containing neurotransmitter are released

Adaptation is defined as the decline in response of a sensory receptor to a continual steady stimulus

Afferent refers to a neuron or pathway that sends information into the CNS, typically sensory in nature

Agonist refers either to: (i) an agent that binds and activates a membrane receptor, and which in some cases defines that receptor type, e.g. the N-methyl-d-aspartate (NMDA) glutamate receptor; or (ii) a muscle that acts in a similar fashion to that performing the primary movement around a joint

Antagonist refers either to: (i) an agent that blocks the action of an agonist at its membrane receptor; or (ii) a muscle that opposes those muscles performing a specific movement around a joint. For example, the triceps muscle acts antagonistically to the biceps muscle in elbow flexion

Antidromic refers to the propagation of an action potential along an axon in a direction that is the reverse of the normal direction of transmission, and is typically only seen experimentally

Apoptosis an intrinsic cellular programme that once activated leads to cell death

Arachnoid membrane is a thin, transparent membrane which is avascular. It has trabeculae that communicate with the pia mater and in places pierces the dura to form arachnoid villi that are important in the absorption of cerebrospinal fluid

Association cortex are those areas that receive multiple inputs from sensory cortical areas subserving different modalities. They thus have a role in higher sensory processing as well as the formulation of motor responses to sensory stimuli. The posterior parietal, temporal and prefrontal cortical areas are typically described as association cortices

Astrocyte is a type of neuroglial cell that is found throughout the CNS and which has a number of important homeostatic and structural functions including the formation and maintenance of the blood-brain barrier

Autonomic nervous system (ANS) has a central and peripheral component and is concerned with the innervation of internal and glandular organs. It is made up of the sympathetic, parasympathetic and enteric nervous systems

Axoaxonic; axodendritic and axosomatic synapses refer to synapses made between an axon and another axon, dendrite or neuronal cell body (soma), respectively

Axolemma is the plasma membrane of the axon

Axon is the neuronal process that originates at the axon hillock and conducts information away from the neuronal cell body to the nerve terminal and synapses. There is only ever one axon per neuron, although that axon may have multiple branches

Axon collateral is a branch of the main axon, and originates at the node of Ranvier

Axon hillock is the site at which the axon originates from the neuronal cell body, and is in continuity with the initial segment of the axon. This is the most excitable part of a neuron as a result of its high density of sodium channels and is therefore the site of initiation of the action potential

Axoplasmic flow or axonal transport refers to the transport of macromolecules and membranous organelles along the axon. Typically this is away from the cell body (anterograde) and towards the nerve terminals, although retrograde transport does occur. Axonal transport can be either fast or slow in nature, and employs a number of motor proteins as well as filaments

Basal ganglia refers to the following collection of subcortical structures which are found in each cerebral hemisphere: the caudate and putamen (neostriatum); the globus pallidum; the substantia nigra and the subthalamic nucleus.

Basilar membrane is found in the cochlea and on it sits the organ of Corti. Its width and flexibility changes with distance along the cochlea, and these properties allow it to perform an important function in frequency tuning within the cochlea

Blobs are cytochrome oxidase-rich areas in the primary visual cortex, found predominantly in cortical layers II and III and to a lesser extent layers V and VI

Blood-brain barrier (BBB) is formed by the very high resistance tight junctions between the cerebral capillary endothelial cells, which are maintained in this state by astrocytes. The BBB serves to prevent the passage of large molecules and cells into the CNS

Brainstem is that part of the brain that connects the spinal cord to the cerebral hemispheres and from which 10 out of the 12 cranial nerves originate. It is connected to the cerebellum via three pairs of cerebellar peduncles. It is composed of the medulla, pons and midbrain and controls many basic functions such as respiration, circulation and wakefulness

Broca's area is found in the posterior part of the dominant (usually left) prefrontal cortex and is important in the expression of language as speech. Damage to this area causes an expressive dysphasia

Cauda equina refers to the descending ventral and dorsal roots of the lumbar, sacral and coccygeal nerves that lie in the subarachnoid space at the caudal tip of the spinal cord

Central nervous system (CNS) embraces those cells that lie within spinal cord and brain (brainstem, cerebellum and the cerebral hemispheres). It is composed of neurons and a number of different types of neuroglial cells

Central pattern generators refer to networks of neurons in the spinal cord (and brainstem) that are capable of generating their own outputs to motorneurons independently of any descending or peripheral sensory input. They are important in locomotion and respiration

Centre-surround (receptive field) organisation is found mainly within the visual system and describes a situation in which the stimulus at the centre of the receptive field elicits one response (e.g. a depolarisation or 'on' centre response), while an annulus of light around it produces the opposite effect (e.g. a hyperpolarisation or 'off' surround response)

Centrifugal nerve fibres project out of the CNS to the periphery. The term is generally reserved for sensory systems rather than motor pathways, and refers to projections down the sensory pathway which may include a CNS input to the sensory receptor itself (e.g. hair cells of the cochlea)

Cerebellum is found in the posterior fossa behind the brainstem to which it is connected by three pairs of cerebellar peduncles. It is important for learning and storing motor acts and in the coordination of voluntary movement

Cerebral cortex represents the outer layer of the cerebral hemisphere and contains neurons that are organised in terms of horizontal layers and vertical columns

Cerebral peduncle connects the midbrain to the thalamus and consists of the tegmentum, substantia nigra and crus cerebri that contains the descending motor and ascending sensory pathways that originate or relay to the cerebral cortex.

Cerebrospinal fluid (CSF) is found within the CNS ventricular system and subarachnoid space and is formed by the choroid plexus. It is reabsorbed by arachnoid granulations

Circadian rhythms refers to any naturally occurring, approximately 24 hour (daily), rhythm

Closed-loop (or reflexly controlled) movements are those that are guided by inputs from sensory systems

Cochlea is found in the inner ear and contains the receptors for hearing

Columnar hypothesis refers to conceptual organisation of the cerebral cortex in terms of vertical columns of cells with similar functional properties

Complex cells are found mainly in the primary visual cortex and were so-named by Hubel and Wiesel. These cells have large receptive fields that are maximally activated by a line or bar of illumination of a given orientation moving in a particular direction, that direction often being orthogonal to the line orientation

Contralateral on the opposite side

Corpus callosum is the largest commissure in the whole CNS and connects the two cerebral hemispheres

Corpus striatum consists of caudate nucleus, putamen and globus pallidus

Corticobulbar tracts refer to those pathways that originate in the cortical motor areas and terminate in the brainstem

Corticospinal or pyramidal tract takes its origin from the Betz cells in the primary motor cortex, as well as the primary somatosensory cortex and premotor cortical areas. Although it predominantly projects to the motorneurons, it also has inputs to other structures such as the dorsal column nuclei

Cotransmission refers to the release of more than one neurotransmitter at a synapse

Cranial nerves refer to the 12 sets of nerves that originate from the brainstem, retina and nose and which mediate the special senses as well as providing the motor and sensory innervation of the head and neck

Critical firing threshold is the membrane potential at which sufficient sodium channels are open to allow for the generation of an action potential

Critical period is that time in development when there is maximum plasticity in the evolving neural system, such that it can be modified by environmental inputs. It is best described in the developing visual system

Cyclic adenosine monophosphate (cAMP) is made by the enzyme adenyl cyclase and serves to trigger protein phosphorylation by cAMP protein kinases. It is thus an important secondary messenger in many cells, including neurons

Cytoskeleton refers to the network of microfilaments, microtubules, neurofilaments and an assortment of proteins which maintains neuronal architecture and allows it to modify its appearance during development, growth or injury

Decussation refers to the crossing of a neural pathway in the spinal cord or brainstem

Dendrites are the neuronal cell processes that taper from the soma outwards, branch profusely and are responsible for conveying information to the neuron

Depolarisation is a shift in the membrane potential of a cell to a less negative value. It increases the likelihood that a neuron will reach the critical firing threshold for an action potential and so is excitatory in nature

Desensitisation is the process in which the binding of a ligand to its receptor leads to a decreased response. It is also termed down regulation and in time there is an actual decrease in receptor number as a result of increased endocytosis of the ligand-bound receptors

Diencephalon refers to the thalamus, hypothalamus, subthalamus and epithalamus

Dorsal columns are those ascending sensory tracts in the spinal cord that relay information from the large myelinated sensory nerve fibres conveying light touch, joint position sense and vibration perception. They are preferentially damaged in tabes dorsalis, subacute degeneration of the spinal cord and Friedreich's ataxia

Dorsal column nuclei are found in the medulla and receive a synaptic input from the dorsal columns. They project to the thalamus as the medial lemniscus

Dorsal horn is that part of the spinal cord where the sensory afferent fibres enter. It contains a number of interneurons as well as receiving an input from descending pathways originating in the brainstem

Dorsal root ganglia are found just outside the spinal cord and contain the cell bodies of the sensory neurons in the PNS

Dorsolateral descending motor pathways refers to the corticospinal and rubrospinal tracts that preferentially innervate those motorneurons that control the distal musculature

Down regulation see Desensitisation

Dura mater is a thick tough membrane lying close to the cranium and vertebrae. It is separated from the arachnoid membrane by the subdural space. In the spinal cord the inner and outer layers of the dura mater are separated by the extradural space

Efferent refers to a neuron or pathway that transmits signals away from the CNS to the periphery or some other CNS site

Electrical synapses allow the direct flow of current from a pre-synaptic to a postsynaptic cell. They typically consist of gap-junction channels

Endocytosis refers to the process in which a cell internally recycles part of its own membrane; for example, neurotransmitter receptors or fused vesicle membrane in the presynaptic nerve terminal

Endolymph is the fluid found within the scala media of the cochlea. It has a high potassium concentration, similar to intracellular fluid

Endorphins and enkephalins are naturally occurring opioid-like substances found in the nervous system. They are peptides that bind to specific receptors and are intimately involved in pain processing

End-plate is the region in muscle cells where the axon from the motorneuron contacts and makes a synapse

End-plate potential (epp) is the depolarisation seen at the neuromuscular junction when several vesicles of transmitter are released. It is made up of a number of miniature end-plate potentials, and if sufficiently large will reach threshold for action potential generation in the postsynaptic muscle fibre

Enteric nervous system controls the gut musculature and is part of the autonomic nervous system

Ependymal cells line the ventricular system of the brain and central canal of the spinal cord

Equilibrium potential is the membrane potential for a given ion species at which the electrical force driving it in one direction is countered by an equal chemical force in the opposite direction. The electrical force is determined by the charge on the membrane and the chemical force by the concentration gradient of the ion across the membrane. It can be calculated using the Nernst equation.

Excitatory postsynaptic potential (EPSP) is the depolarisation of a postsynaptic membrane in response to a synaptic input which increases the probability that a cell will fire an action potential

Exocytosis is the release of intracellular vesicles (which contain neurotransmitter) by a process involving the docking and fusion of the vesicular membrane with the membrane of the cell. This is the mode of release of neurotransmitter at chemical synapses

Extrafusal fibres are the main contractile elements of striated muscle and are found outside the muscle spindle (cf intrafusal fibres)

Extrapyramidal disorders are those conditions which are thought to be caused by a dysfunction of the basal ganglia (e.g. Parkinson's disease)

Extrapyramidal tracts refers to those descending motor pathways that do not take their origin from the cerebral cortex. It thus includes the rubrospinal, reticulospinal, tectospinal and vestibulospinal tracts

Fasciculus is a tract or bundle of nerve fibres

Foramen magnum is the opening at the base of the skull where the brainstem ends and the spinal cord begins

Frequency coding (temporal) process by which the characteristics of a sensory stimulus are encoded in the form of patterns of action potentials

G-protein is a GTP-dependent membrane protein that links a receptor for a neurotransmitter to an intracellular enzyme

Ganglion refers to a group of functionally related cell bodies in the PNS

Gate theory refers to the hypothesis put forward by Melzack and Wall in the mid 1960s that postulated that the passage of nociceptive information across the dorsal horn could be inhibited by large fibre synaptic inputs. It forms the rationale for using transcutaneous nerve stimulation as a treatment for pain

Gating is the active transition of an ion channel from an open to a closed state

Generator potential is the depolarisation induced in the terminal of a sensory receptor, which if sufficiently large can initiate an action potential in the afferent axon

Glia or neuroglia form the other major cell class in the nervous system with neurons. There are several different types of glial cell within the CNS but only one in the PNS (Schwann cells)

Golgi tendon organs are sensory receptors found in the tendons of muscles. They thus lie in series with the muscle fibres and so primarily signal tension within the muscle. They relay information to the spinal cord in the form of a Ib afferent nerve

Gray or Grey matter is that part of the nervous system that contains neuronal cell bodies

Gustatory system are those neurons and pathways involved in taste

Habituation is a learning process in which a subject decreases his/her behavioural response to a repetitive stimulus

Hair cells are the sensory receptors of hearing in the cochlea of the ear as well as of balance in the vestibular apparatus of the inner ear

Hippocampal complex is found in the medial temporal lobe and consists of the dentate gyrus, CA1-CA4 subfields of the hippocampus proper and the subiculum. It is part of the limbic system and is especially susceptible to hypoxic and ischaemic damage. It is thought to be important in memory and has been the site of most research on long-term potentiation

Hyperalgesia is the evocation of pain by a weakly noxious stimulus

Hypercolumn is defined in the primary visual cortex as that area of cortex which contains an ocular dominance column for each eye and a complete set of orientation columns, covering 180° of orientation

Hypercomplex or end-stopped cells (after Hubel and Wiesel) are found in the visual cortex and have large receptive fields which respond maximally to a line or bar of illumination of given orientation and length

Hyperpolarisation is a shift in membrane potential to a more negative value. It reduces the probability of an action potential being generated and is thus inhibitory

Hypothalamus is part of the diencephalon. It lies just above the pituitary gland and has a number of important neural and endocrine functions

Iatrogenic disorders are those caused inadvertently as a consequence of medical treatment

Inhibitory postsynaptic potential (IPSP) is the hyperpolarisation of a postsynaptic membrane in response to a synaptic input which decreases the probability that a cell will fire an action potential

Initial segment of the axon is that part of the axon, adjacent to the axon hillock, which has the highest density of sodium channels and which is the most excitable part of a neuron. It is thus the site of action potential generation

Internal capsule large mass of white matter running between the basal ganglia and thalamus containing many ascending and descending pathways to and from the cortex

Interneurons are neurons with either small axons that project locally within the CNS (so-called local interneurons) or long axons that relay to distant CNS targets (relay interneurons)

Intrafusal fibres are the specialised muscle fibres found within the muscle spindle

Ion channel is a transmembrane pore that allows ions to flow across a membrane. It exists in at least an open and closed state and is regulated by either a change in membrane potential (voltage-gated channels) or the binding of a specific neurotransmitter or chemical substance (ligand-gated or chemically activated channels)

Ipsilateral on the same side

Junctional fold is the specialisation seen in the postsynaptic muscle fibre at the neuromuscular junction

Kindling is an experimentally induced process in which a repeated focal application of an initially subconvulsive electrical stimulus ultimately results in a partial or generalised seizure

Labyrinth is made up of the utricle and sacculus and together with the semicircular canals forms the peripheral vestibular system of the inner ear

Lateral inhibition is the reciprocal suppression of submaximally excited inputs by neighbouring neurons in a sensory pathway. It serves to increase contrast within the sensory pathway

Ligand is a substance that binds to a membrane receptor or ion channel. Most ligands are either neurotransmitters, hormones or drugs

Limbic system is a collection of structures that lie along the medial aspect of the temporal (and to a lesser extent frontal and parietal) lobe and includes the cingulate gyrus, parahippocampal structures, entorhinal cortex, hippocampal complex, septal nuclei and amygdala. It is involved in emotional responsiveness as well as having an important role in memory acquisition. Many people object to the use of this term, complaining that it is too vague to be of value

Long latency or transcortical reflexes refer to the delayed and smaller electromyographic changes that are seen following the sudden stretch of a muscle. The dorsal column-medial lemniscal system and corticospinal tract are thought to relay the afferent and efferent limbs of this reflex, that may have a role in load compensation

Long-term depression (LTD) is defined as a decrease in strength of synaptic transmission with repetitive use that lasts for more than a few minutes

Long-term potentiation (LTP) is defined as an increase in strength of synaptic transmission with repetitive use that lasts for more than a few minutes. In the hippocampus LTP can be triggered by less than 1 second of intense synaptic activity and lasts for hours or more. It may, with LTD, underlie memory acquisition

Lower motoneurons (LMNs) are those motorneurons that directly innervate the muscles. They are therefore found in some of the cranial nerve nuclei as well as the anterior horn of the spinal cord. Damage to the LMN results in muscle weakness, wasting with a loss of reflexes

Major histocompatibility complex (MHC) is important in regulating the activity of all immune responses involving T-lymphocytes, as the T-lymphocyte receptor requires the presentation of foreign antigen with a class of MHC molecule. All cells express MHC class I but only a few specialised cells express MHC class II. These latter cells are termed antigen presenting cells and are important in controlling the extent to which an immunological reaction can be mounted. In the CNS, MHC class II expression is low and probably restricted to microglial cells

Medial lemniscus is the fibre tract connecting the dorsal column nuclei to the ventroposterior nucleus of the thalamus

Medial longitudinal fasciculus connects the oculomotor nuclei as well as projecting down into the upper cervical cord. A lesion to the brainstem portion of the fasciculus commonly occurs in multiple sclerosis and produces an internuclear ophthalmoplegia

Medulla forms the lower part of the brainstem, lying between the cervical spinal cord and pons. It contains the nuclei of the lower cranial nerves (IX-XII), as well as many critical cardiorespiratory centres

Meissner's corpuscles are cutaneous receptors found close to the surface of hairless (glabrous) skin which have small receptive cells and rapidly adapt to an applied sensory stimuli. They are thus classified as rapidly adapting type I (RAI) receptors and are sensitive to low-frequency mechanical stimuli or flutter

Memory is the storage of learned information

Meninges are the membranes separating the skull and vertebral column from the brain and spinal cord (see dura mater, arachnoid membrane and pia mater)

Merkel's disc is a cutaneous receptor of the slowly adapting type I phenotype (SAI) that lies close to the surface of glabrous skin. They are sensitive to sustained pressure

Metabotropic receptors respond on activation with glutamate binding by initiating a number of intracellular biochemical events which modulate synaptic and neuronal activity. They are not directly linked to any specific ion channels

Microglial cells are a type of neuroglia that are similar to the peripheral macrophage. They probably play an important part in the immune responses of the CNS

Midbrain lies at the top of the brainstem between the pons and cerebral peduncle. It contains the third and fourth cranial nerve nuclei, as well as a number of other important structures such as the red nucleus, substantia nigra, periaqueductal grey matter and colliculi

Miniature end-plate potential (mepp) represents the post-synaptic membrane potential in the muscle fibre in response to the release of one vesicle of neurotransmitter from the motorneuron nerve terminal. The release of several vesicles results in a summation of mepps to give an end-plate potential (epp)

Modality is the type of preferred sensory stimulus transduced and relayed by a sensory system

Motorneurons (MNs) are those neurons that are directly involved in the activation of muscles. They can broadly be defined in terms of those directly innervating muscles-the lower motorneurons (LMNs)-and those that innervate the LMN, the upper motorneurons (UMNs). The LMN can be further subdivided into those that innervate the muscle spindle (gamma-motorneuron) and those that innervate the extrafusal (force-generating) muscle fibres (alpha-motorneuron)

Motor unit refers to the relationship of a single motorneuron axon to the number of muscle fibres it innervates

Muscle spindle is an encapsulated sensory organ that lies within muscles and conveys information to the spinal cord as well as receiving a specific input from the anterior horn gamma-motorneuron. It is important in setting muscle tone, mediating the tendon stretch reflex, as well as providing useful proprioceptive information to the CNS

Myelin sheath is the fatty layer of insulation that is wrapped around most large nerve fibres and which allows for rapid, unattentuated conduction of the action potential

Neostriatum refers to the caudate nucleus and putamen and is the major receiving area of the basal ganglia

Nernst equation is used to calculate the equilibrium potential for a particular ion

Neuromuscular junction (NMJ) is the point of communication between the lower motorneuron axon nerve terminal and the muscle fibre it innervates

Neural Stem cell These cells are found in the developing brain (embryonic neuro stem cells) as well as at certain sites in the adult CNS. They are capable of dividing to form neurons, astrocytes, olyodendrocytes, as well as more neural stem cells. In the adult brain they may have a role in repair and memory

Neuron (or neurone) is one of the two major classes of cell within the nervous system. Neurons can be classified into one of three major types: sensory, motor and interneurons. They generate and propagate action potentials and communicate with each other through billions of connections termed synapses

Neurotransmitter is a chemical substance released by a presynaptic nerve terminal that diffuses and binds to specific postsynaptic receptors which leads to an alteration in current flow in that postsynaptic cell

Neurotrophic factors are specific molecules that appear to promote the survival and/or mitogenesis of neural cells

Nitric oxide (NO) is a short-lived gas that readily passes through cell membranes and which may mediate long-term potentiation. It is known to activate a number of intracellular secondary messengers and so may have a number of other roles within the CNS

N-methyl-d-aspartate (NMDA) glutamate receptor is a type of glutamate receptor that may be important in a number of different synaptic processes, including long-term potentiation

Nociceptors are sense organs detecting damaging stimuli which are often perceived as being painful

Nodes of Ranvier are the gaps in the myelin sheath where the axolemma is directly exposed to tissue fluid. They contain ion channels and are responsible for propagating the action potential down the axon by saltatory conduction. They are also the site of origin for axon collaterals

Nucleus is a collection of functionally related cell bodies in the CNS (cf ganglia in PNS)

Nystagmus is an eye movement in which there is a biphasic oscillation of the eyes. It can be seen normally under some circumstances (such as the extremes of gaze) as well as in a number of diseases affecting the brainstem, vestibular apparatus and cerebellum

Ocular dominance columns were first described by Hubel and Wiesel in the primary visual cortex. Each ocular dominance column represents a vertical collection of neurons that have a dominant input from one eye. This ocular dominance is determined by the thalamic input to layer IV of the primary visual cortex

Oculomotor nuclei are the third, fourth and sixth cranial nerve nuclei located in the midbrain and pons responsible for controlling the extraocular muscles and linked to each other by the medial longitudinal fasciculus

Oligodendrocyte is a type of neuroglial cell found in the CNS that creates the myelin sheath around the axon

Open-loop (or volitional) movements are those triggered by a sensory cue or some internal desire to move

Organ of Corti is found in the cochlea and contains the hair cells important in auditory transduction

Orientation selective columns were first described by Hubel and Wiesel in the primary visual cortex, and represent a vertical collection of neurons that have a preferred orientation of visual stimulus

Pacinian corpuscle is a cutaneous (and visceral) receptor that is classified as being rapidly adapting type II (RAII). It lies deep in the dermis of the skin and is sensitive to high-frequency mechanical stimuli or vibration

Parallel processing is the relaying and analysis of sensory information down a number of parallel pathways, each performing some relatively specific processing. This is best seen in the visual system

Parasympathetic nervous system is one of the parts of the autonomic nervous system. It uses acetylcholine as its postganglionic neurotransmitter

Peripheral nervous system (PNS) is defined as those nerves that lie outside the brain, brainstem or spinal cord. The PNS consists of nerve trunks made up of both afferent fibres or axons conducting sensory information to the spinal cord and brainstem and efferent fibres transmitting impulses primarily to the muscles

Phosphorylation is the covalent addition of a phosphate group to a protein by a protein kinase with an alteration in the activity of the protein

Pia mater is a vascular membrane that covers the surface of the CNS

Plasticity can occur at the level of synapses (see Long-term depression and Potentiation) as well as within neural systems (e.g. visual cortex). It refers to the ability to change the efficacy of synaptic transmission and neuronal connections in the face of altered afferent activity

Pons is found in the brainstem between the medulla and midbrain. It contains part or all of the fifth to eighth cranial nerve nuclei as well as relaying the major cortical input to the cerebellum

Positive feedback refers to the process whereby a disturbance about a homeostatic set-point results in an increase in that disturbance. This form of feedback is rarely used in biological systems because of its explosive and damaging nature, but such a system operates in the generation of the upstroke of the action potential

Posterior fossa refers to that part of the skull that lies below the tentorial membrane and above the foramen magnum, and which contains the brainstem and cerebellum

Postsynaptic cell is that neuron or cell that has an altered excitability as a result of binding a neurotransmitter released by an afferent presynaptic nerve terminal

Premotor cortex refers to the lateral part of Brodmann's area 6 which is just anterior to the primary motor cortex. It is involved in the planning and initiation of movement as well as the control of proximal musculature. It is to be distinguished from the premotor cortical areas which refers to all prefrontal cortical areas that project to the primary motor cortex

Presynaptic cell is that neuron which synapses on to another neuron or cell

Primary afferent (primary sensory neuron) is the first neuron in the sensory pathway; it thus refers to the sensory receptor, its afferent axon and cell body together with the synaptic contacts in the spinal cord

Principle of recruitment corresponds to the order in which different muscle fibres are activated (see Size principle)

Proprioception the sense of joint/body position

Pyramidal tract see Corticospinal tract

Quantal transmission refers to the vesicular release of neurotransmitters at the chemical synapse. The quantum of transmitter is thought to be that contained in a single presynaptic vesicle

Receptive field of a sensory receptor represents the space within the receptive sheet (e.g. skin, retina, etc.) where the receptor is located and able to respond to stimuli

Receptor potential refers to potential change in a sensory receptor to an appropriate stimulus

Refractory period refers to that period of time after the generation of an action potential when the membrane is either inexcitable or only activated to submaximal responses by suprathreshold stimuli

Resting membrane potential refers to the equilibrium potential for the neuronal membrane in the non-activated state and approximates to the equilibrium potential for potassium

Reticular formation refers to a series of poorly defined structures in the brainstem that have diffuse projections both rostrally to the cerebral hemispheres (particularly the thalamus) and caudally to the spinal cord

Retinotopic map or projection refers to the orderly projection of retinal axons to the tectum and thalamus and the subsequent projection from the lateral geniculate nucleus of the thalamus to the visual cortex

Rexed laminae refers to a series of morphologically different areas of the spinal cord grey matter

Ruffini ending is a cutaneous receptor found deep within the dermis. It is classified as a slowly adapting type II receptor (SAII) and is sensitive to lateral stretching of the skin

Saccades are the rapid movement of the eyes to a new visual target or fixation point

Saltatory conduction is that seen in myelinated nerve fibres where the action potential is generated only at the nodes of Ranvier

Sarcoplasmic reticulum (SR) is found in striated skeletal muscle and envelops the myofibrils and is important as an intracellular store of Ca²⁺

Schwann cells are found in the PNS and are responsible for providing the myelin sheath to axons in peripheral nerves

Secondary messengers are substances produced within a cell subsequent to the binding of some chemical to its membrane receptor. This substance then acts in a number of different ways within that cell to produce its effect. Examples of secondary messengers include cAMP, cGMP, diacylglycerol (DAG) and inositol triphosphate (IP³)

Secretion refers to the release of substances by vesicular exocytosis

Semi-circular canals are found in the inner ear and are part of the vestibular system

Serial processing refers to the relaying and analysis of sensory information along a single pathway, with each higher stage of the pathway performing some relatively more complex processing. This is well demonstrated in the visual system

Simple cells (after Hubel and Wiesel) are neurons found in the visual cortex that have small receptive fields which respond maximally to a line or bar of illumination of a given orientation

Size principle is the order of recruitment of motorneurons to a given input by virtue of the size of their cell bodies

Somatotopy or somatotopic representation refers to the organisation of the ascending dorsal column-medial lemniscal pathway in terms of the location of the sensory fibres from cutaneous receptors. This ensures that the input from receptors in neighbouring areas of skin is maintained in the ascending projection to the cortex

Spatial summation is performed in the postsynaptic cell and refers to the integration of all synaptic inputs at a given point in time at the trigger zone

Specificity of a sensory receptor refers to its capacity to respond selectively to a particular type of stimulus

Spinocerebellar tracts originate in the spinal cord and project to the cerebellum. The dorsal spinocerebellar tract preferentially relays information from the muscle spindle and projects through the inferior cerebellar peduncle. In contrast, the ventral spinocerebellar tract relays information on spinal cord interneuronal activity and projects to the cerebellum through the superior cerebellar peduncle

Spinothalamic tract forms part of the anterolateral system relaying information on pain and temperature from the cutaneous receptors to the thalamus. The spinoreticular and spinomesencephalic tracts are the other two pathways making up the anterolateral system, although for simplicity these two tracts are often grouped together to form the spinoreticulothalamic pathway

Substantia nigra is found in the midbrain. There are two parts to it: the pars compacta provides a dopaminergic input to the neostriatum, while the pars reticulata component provides a GABAergic input to the thalamus and brainstem

Sudomotor refers to the autonomic innervation, and thus activity, of sweat glands

Sulcus refers to the groove between two gyri in the cerebral cortex

Supersensitivity is the process in which the binding of a ligand to its receptor leads to a greater than normal response. It is also termed upregulation and in time there may be an actual increase in receptor number. It typically occurs in situations where there has been reduced synaptic activity

Supplementary motor area (SMA) corresponds to the medial part of Brodmann's area 6. It is important in the planning and initiation of movement

Sympathetic nervous system is one of the three major subdivisions of the autonomic nervous system. It uses noradrenaline as its postsynaptic neurotransmitter

Synapse is the specialised site of communication between two cells, typically neurons

Synaptic bouton is the presynaptic nerve terminal enlargement that contains the vesicles and apparatus for neurotransmitter release

Synaptic cleft is the extracellular gap between the presynaptic nerve terminal and the postsynaptic nerve process. It is typically in the region of 50 nm

Synaptic vesicles are found in the nerve terminal and contain the neurotransmitter. They fuse with the presynaptic nerve terminal membrane in response to a depolarising input, and by so doing release their neurotransmitter which can then bind to receptors in the postsynaptic (and at some synapses, presynaptic) nerve process

Tectorial membrane is found in the scala media of the cochlea and overlies the hair cells of the organ of Corti

Tentorial membrane is a fold of the dura mater that has its free margin surrounding the midbrain and a fixed margin attached to the skull at the top of the posterior fossa. It separates the cerebellum from the cerebral hemispheres

Temporal summation is performed in the postsynaptic cell and refers to the integration of synaptic inputs over time

Tetanic stimulation refers to high frequency stimulation of the presynaptic neuron

Thalamus is part of the diencephalon and is important not only in relaying information to the cerebral cortex but in controlling the degree of arousal and attention within CNS neural systems

Transcortical reflexes see Long latency reflexes

Transduction in sensory receptors involves the conversion of a stimulus from the external or internal environment into an electrical signal for transmission through the nervous system

Tranverse or T-tubules are specialised invaginations of the sarcolemma in striated muscle, which are important in conveying the action potential deep into the muscle fibre

Triad refers to the arrangement in skeletal muscle of a T-tubule between two terminal cisternae of the sarcoplasmic reticulum

Trigger zone refers to that part of the neuron where an action potential is initiated. In neurons, other than sensory receptors, this is usually the initial segment of the axon

Upper motorneurons (UMNs) are those motorneurons that both directly and indirectly innervate the lower motorneurons of the brainstem and spinal cord. Damage to the UMN and its caudal projection results in muscle weakness, increased muscle tone, increased tendon reflexes but no muscle wasting

Up regulation see Supersensitisation

Ventromedial descending motor pathways refers to the reticulospinal, tectospinal, vestibulospinal tracts that preferentially innervate those motorneurons that control the proximal/axial musculature

Vestibulo-ocular reflex maintains visual fixation with head movement

Weber-Fechner law describes the relationship that predicts that the ability to detect a change in intensity stimulus at a given intensity is constant

Wernicke's area is that part of the dominant (usually left) parietal cortex that is concerned with the comprehension of speech; damage to this area results in a receptive dysphasia

White matter are those parts of the CNS that primarily contain nerve fibres and glial cells

 

ที่มา: Neuroscience at a Glance Second Edition

By: Roger Barker, Stephen Barasi (University of Cardiff) and Michael J Neal (United Medical and Dental Schools of Guy's & St Thomas's Hospital)

http://www.medicalneuroscience.com/ngloss.htm

         A

        abreaction An emotional release or discharge after recalling a painful experience that has been repressed because it was not consciously tolerable.  Often the release is surprising to the individual experiencing it because of it's intensity and the circumstances surrounding its onset.  A therapeutic effect sometimes occurs through partial or repeated discharge of the painful affect.

abstract attitude (categorical attitude) This is a type of thinking that includes voluntarily shifting one's mind set from a specific aspect of a situation to the general aspect; It involves keeping in mind different simultaneous aspects of a situation while grasping the essentials of the situation.  It can involve breaking a situation down into its parts and isolating them voluntarily; planning ahead ideationally; and/or thinking or performing symbolically. A characteristic of many psychiatric disorders is the person's inability to assume the abstract attitude or to shift readily from the concrete to the abstract and back again as demanded by circumstances.

abulia  A lack of will or motivation which is often expressed as inability to make decisions or set goals. Often, the reduction in impulse to action and thought is coupled with an indifference or lack of concern about the consequences of action.

acalculia The loss of a previously possessed ability to engage in arithmetic calculation.

acculturation difficulty A problem stemming from an inability to appropriately adapt to a different culture or environment. The problem is not based on any coexisting mental disorder.

acetylcholine A neurotransmitter in the brain, which helps to regulate memory, and in the peripheral nervous system, where it affects the actions of skeletal and smooth muscle.

acting out This is the process of expressing unconscious emotional conflicts or feelings via actions rather than words. The person is not consciously aware of the meaning or etiology of such acts. Acting out may be harmful or, in controlled situations, therapeutic (e.g., children's play therapy).

actualization The realization of one's full potential - intellectual, psychological, physical, etc.

adiadochokinesia  The inability to perform rapid alternating movements of one or more of the extremities.  This task is sometimes requested by physicians of patients during physical examinations to determine if there exists neurological problems.

adrenergic This refers to neuronal or neurologic activity caused by neurotransmitters such as epinephrine, norepinephrine, and dopamine.

affect This word is used to described observable behavior that represents the expression of a subjectively experienced feeling state (emotion). Common examples of affect are sadness, fear, joy, and anger. The normal range of expressed affect varies considerably between different cultures and even within the same culture. Types of affect include: euthymic, irritable, constricted; blunted; flat; inappropriate, and labile.

affective disorders Refers to disorders of mood.  Examples would include Major Depressive Disorder, Dysthymia, Depressive Disorder, N.O.S., Adjustment Disorder with Depressed Mood, Bipolar Disorder...

age-associated memory impairment (AAMI) The mild disturbance in memory function that occurs normally with aging; benign senescent forgetfulness.  Such lapses in memory are lately humorously referred to as representing "a senior moment".

agitation (psychomotor agitation) Excessive motor activity that accompanies and is associated with a feeling of inner tension. The activity is usually nonproductive and repetitious and consists of such behavior as pacing, fidgeting, wringing of the hands, pulling of clothes, and inability to sit still.

agnosia Failure to recognize or identify objects despite intact sensory function; This may be seen in dementia of various types.  An example would be the failure of someone to recognize a paper clip placed in their hand while keeping their eyes closed.

agonist medication A chemical entity that is not naturally occuring within the body which acts upon a receptor and is capable of producing the maximal effect that can be produced by stimulating that receptor. A partial agonist is capable only of producing less than the maximal effect even when given in a concentration sufficient to bind with all available receptors.

agonist/antagonist medication A chemical entity that is not naturally occuring within the body which acts on a family of receptors (such as mu, delta, and kappa opiate receptors) in such a fashion that it is an agonist or partial agonist on one type of receptor while at the same time it is also an antagonist on another different receptor.

agoraphobia Anxiety about being in places or situations in which escape might be difficut or embarrassing or in which help may not be available should a panic attack occur. The fears typically relate to venturing into the open, of leaving the familiar setting of one's home, or of being in a crowd, standing in line, or traveling in a car or train. Although agoraphobia usually occurs as a part of panic disorder, agoraphobia without a history of panic disorder has been described as also occuring without other disorders.

agraphia The loss of a pre-existing ability to express one's self through the act of writing.

akathisia Complaints of restlessness accompanied by movements such as fidgeting of the legs, rocking from foot to foot, pacing, or inability to sit or stand. Symptoms can develop within a few weeks of starting or raising the dose of traditional neuroleptic medications or of reducing the dose of medication used to treat extrapyramidal symptoms. akathisia is a state of motor restlessness ranging from a feeling of inner disquiet to inability to sit still or lie quietly.

akinesia A state of motor inhibition or reduced voluntary movement.

akinetic mutism A state of apparent alertness with following eye movements but no speech or voluntary motor responses.

alexia Loss of a previously intact ability to grasp the meaning of written or printed words and sentences.

alexithymia A disturbance in affective and cognitive function that can be present in an assortment of diagnostic entities.  Is common in psychosomatic disorders, addictive disorders, and posttraumatic stress disorder. The chief manifestations are difficulty in describing or recognizing one's own emotions, a limited fantasy life, and general constriction in affective life.

algophobia Fear of pain.

alienation The estrangement felt in a setting one views as foreign, unpredictable, or unacceptable. For example, in depersonalization phenomena, feelings of unreality or strangeness produce a sense of alienation from one's self or environment.

alloplastic Referring to adaptation by means of altering the external environment. This can be contrasted to autoplastic, which refers to the alteration of one's own behavior and responses.

alogia An impoverishment in thinking that is inferred from observing speech and language behavior. There may be brief and concrete replies to questions and restriction in the amount of spontaneous speech (poverty of speech). Sometimes the speech is adequate in amount but conveys little information because it is overconcrete, overabstract, repetitive, or stereotyped (poverty of content).

ambivalence The coexistence of contradictory emotions, attitudes, ideas, or desires with respect to a particular person, object, or situation. Ordinarily, the ambivalence is not fully conscious and suggests psychopathology only when present in an extreme form.

amentia Subnormal development of the mind, with particular reference to intellectual capacities; a type of severe mental retardation.

amimia A disorder of language characterized by an inability to make gestures or to understand the significance of gestures.

amines Organic compounds containing the amino group. Amines such as epinephrine and norepinephrine are significant because they function as neurotransmitters.

amnesia Loss of memory. Types of amnesia include: anterograde Loss of memory of events that occur after the onset of the etiological condition or agent. retrograde Loss of memory of events that occurred before the onset of the etiological condition or agent.

amok A culture specific syndrome from Malay involving acute indiscriminate homicidal mania .

amygdala This is a structure of the brain which is part of the basal ganglia located on the roof of the temporal horn of the lateral ventricle at the inferior end of the caudate nucleus. It is a structure in the forebrain that is an important component of the limbic system.

amyloid Any one of various complex proteins that are deposited in tissues in different disease processes. These proteins have an affinity for Congo red dye. In neuropsychiatry, of particular interest are the beta-amyloid (A4) protein, which is the major component of the characteristic senile plaques of Alzheimer's disease, and the amyloid precursor protein (APP).

anaclitic In psychoanalytic terminology, dependence of the infant on the mother or mother substitute for a sense of well-being. This is considered normal behavior in childhood, but pathologic in later years.

anal stage The period of pregenital psychosexual development, usually from 1 to 3 years, in which the child has particular interest and concern with the process of defecation and the sensations connected with the anus. The pleasurable part of the experience is termed anal eroticism. 

anamnesis The developmental history of a patient and of his or her illness, especially recollections.

anankastic personality Synonym for obsessive-compulsive personality.

androgyny A combination of male and female characteristics in one person.

anhedonia Inability to experience pleasure from activities that usually produce pleasurable feelings. Contrast with hedonism.

anima In Jungian psychology, a person's inner being as opposed to the character or persona presented to the world. Further, the anima may be the more feminine "soul" or inner self of a man, and the animus the more masculine soul of a woman.

anomie Apathy, alienation, and personal distress resulting from the loss of goals previously valued. Emile Durkheim popularized this term when he listed it as a principal reason for suicide.

anosognosia The apparent unawareness of or failure to recognize one's own functional defect (e.g., hemiplegia, hemianopsia).

antagonist medication A chemical entity that is not naturally occuring within the body which occupies a receptor, produces no physiologic effects, and prevents endogenous and exogenous chemicals from producing an effect on that receptor.

anxiety The apprehensive anticipation of future danger or misfortune accompanied by a feeling of dysphoria or somatic symptoms of tension. The focus of anticipated danger may be internal or external.  Anxiety is often distinguished from fear in that fear is a more appropriate word to use when there exists threat or danger in the real world.  Anxiety is reflective more of a threat that is not apparent or imminent in the real world, at least not to the experienced degree.

apathy Lack of feeling, emotion, interest, or concern.

aphasia An impairment in the understanding or transmission of ideas by language in any of its forms--reading, writing, or speaking--that is due to injury or disease of the brain centers involved in language.

anomic or amnestic aphasia Loss of the ability to name objects.

aphonia An inability to produce speech sounds that require the use of the larynx that is not due to a lesion in the central nervous system.

apperception Perception as modified and enhanced by one's own emotions, memories, and biases.

apraxia Inability to carry out previously learned skilled motor activities despite intact comprehension and motor function; this may be seen in dementia.

assimilation A Piagetian term describing a person's ability to comprehend and integrate new experiences.

astereognosis Inability to recognize familiar objects by touch that cannot be explained by a defect of elementary tactile sensation.

ataxia Partial or complete loss of coordination of voluntary muscular movement.

attention The ability to focus in a sustained manner on a particular stimulus or activity. A disturbance in attention may be manifested by easy distractibility or difficulty in finishing tasks or in concentrating on work

auditory hallucination A hallucination involving the perception of sound, most commonly of voices. Some clinicians and investigators would not include those experiences perceived as coming from inside the head and would instead limit the concept of true auditory hallucinations to those sounds whose source is perceived as being external.

aura A premonitory, subjective brief sensation (e.g., a flash of light) that warns of an impending headache or convulsion. The nature of the sensation depends on the brain area in which the attack begins. Seen in migraine and epilepsy.

autoeroticism Sensual self-gratification. Characteristic of, but not limited to, an early stage of emotional development. Includes satisfactions derived from genital play, masturbation, fantasy, and oral, anal, and visual sources.

automatism Automatic and apparently undirected nonpurposeful behavior that is not consciously controlled. Seen in psychomotor epilepsy.

autoplastic Referring to adaptation by changing the self.

autotopagnosia Inability to localize and name the parts of one's own body. finger agnosia would be autotopagnosia restricted to the fingers.

avolition An inability to initiate and persist in goal-directed activities. When severe enough to be considered pathological, avolition is pervasive and prevents the person from completing many different types of activities (e.g., work, intellectual pursuits, self-care).

B

basal ganglia Clusters of neurons located deep in the brain; they include the caudate nucleus and the putamen (corpus striatum), the globus pallidus, the subthalamic nucleus, and the substantia nigra. The basal ganglia appear to be involved in higher-order aspects of motor control, such as planning and execution of complex motor activity and the speed of movements. Lesions of the basal ganglia produce various types of involuntary movements such as athetosis, chorea, dystonia, and tremor. The basal ganglia are involved also in the pathophysiology of Parkinson's disease, Huntington's disease, and tardive dyskinesia. The internal capsule, containing all the fibers that ascend to or descend from the cortex, runs through the basal ganglia and separates them from the thalamus.

bestiality Zoophilia; sexual relations between a human being and an animal. See also paraphilia.

beta-blocker An agent that inhibits the action of beta-adrenergic receptors, which modulate cardiac functions, respiratory functions, and the dilation of blood vessels. Beta-blockers are of value in the treatment of hypertension, cardiac arrhythmias, and migraine. In psychiatry, they have been used in the treatment of aggression and violence, anxiety-related tremors and lithium-induced tremors, neuroleptic-induced akathisia, social phobias, panic states, and alcohol withdrawal.

bizarre delusion A delusion that involves a phenomenon that the person's culture would regard as totally implausible.

blind spot Visual scotoma, a circumscribed area of blindness or impaired vision in the visual field; by extension, an area of the personality of which the subject is unaware, typically because recognition of this area would cause painful emotions.

blocking A sudden obstruction or interruption in spontaneous flow of thinking or speaking, perceived as an absence or deprivation of thought.

blunted affect An affect type that represents significant reduction in the intensity of emotional expression

body image One's sense of the self and one's body.

bradykinesia Neurologic condition characterized by a generalized slowness of motor activity.

Broca's aphasia Loss of the ability to comprehend language coupled with production of inappropriate language.

bruxism Grinding of the teeth, occurs unconsciously while awake or during stage 2 sleep. May be secondary to anxiety, tension, or dental problems.

C 

Capgras' syndrome The delusion that others, or the self, have been replaced by imposters. It typically follows the development of negative feelings toward the other person that the subject cannot accept and attributes, instead, to the imposter. The syndrome has been reported in paranoid schizophrenia and, even more frequently, in organic brain disease.

catalepsy Waxy flexibility--rigid maintenance of a body position over an extended period of time.

cataplexy Episodes of sudden bilateral loss of muscle tone resulting in the individual collapsing, often in association with intense emotions such as laughter, anger, fear, or surprise.

catatonic behavior Marked motor abnormalities including motoric immobility (i.e., catalepsy or stupor), certain types of excessive motor activity (apparently purposeless agitation not influenced by external stimuli), extreme negativism (apparent motiveless resistance to instructions or attempts to be moved) or mutism, posturing or stereotyped movements, and echolalia or echopraxia

catharsis The healthful (therapeutic) release of ideas through "talking out" conscious material accompanied by an appropriate emotional reaction. Also, the release into awareness of repressed ("forgotten") material from the unconscious. See also repression.

cathexis Attachment, conscious or unconscious, of emotional feeling and significance to an idea, an object, or, most commonly, a person.

causalgia A sensation of intense pain of either organic or psychological origin.

cerea flexibilitas The "waxy flexibility" often present in catatonic schizophrenia in which the patient's arm or leg remains in the position in which it is placed.

circumstantiality Pattern of speech that is indirect and delayed in reaching its goal because of excessive or irrelevant detail or parenthetical remarks. The speaker does not lose the point, as is characteristic of loosening of associations, and clauses remain logically connected, but to the listener it seems that the end will never be reached.

clanging A type of thinking in which the sound of a word, rather than its meaning, gives the direction to subsequent associations.

climacteric Menopausal period in women. Sometimes used to refer to the corresponding age period in men. Also called involutional period.

cognitive Pertaining to thoughts or thinking. Cognitive disorders are disorders of thinking, for example, schizophrenia.

comorbidity The simultaneous appearance of two or more illnesses, such as the co-occurrence of schizophrenia and substance abuse or of alcohol dependence and depression. The association may reflect a causal relationship between one disorder and another or an underlying vulnerability to both disorders. Also, the appearance of the illnesses may be unrelated to any common etiology or vulnerability.

compensation A defense mechanism, operating unconsciously, by which one attempts to make up for real or fancied deficiencies. Also a conscious process in which one strives to make up for real or imagined defects of physique, performance skills, or psychological attributes. The two types frequently merge. See also overcompensation.

compulsion Repetitive ritualistic behavior such as hand washing or ordering or a mental act such as praying or repeating words silently that aims to prevent or reduce distress or prevent some dreaded event or situation. The person feels driven to perform such actions in response to an obsession or according to rules that must be applied rigidly, even though the behaviors are recognized to be excessive or unreasonable.

conative Pertains to one's basic strivings as expressed in behavior and actions

concrete thinking Thinking characterized by immediate experience, rather than abstractions. It may occur as a primary, developmental defect, or it may develop secondary to organic brain disease or schizophrenia.

condensation A psychological process, often present in dreams, in which two or more concepts are fused so that a single symbol represents the multiple components.

confabulation Fabrication of stories in response to questions about situations or events that are not recalled.

confrontation A communication that deliberately pressures or invites another to self-examine some aspect of behavior in which there is a discrepancy between self-reported and observed behavior.

constricted affect Affect type that represents mild reduction in the range and intensity of emotional expression.

constructional apraxia An acquired difficulty in drawing two-dimensional objects or forms, or in producing or copying three-dimensional arrangements of forms or shapes.

contingency reinforcement In operant or instrumental conditioning, ensuring that desired behavior is followed by positive consequences and that undesired behavior is not rewarded.

conversion A defense mechanism, operating unconsciously, by which intrapsychic conflicts that would otherwise give rise to anxiety are instead given symbolic external expression. The repressed ideas or impulses, and the psychological defenses against them, are converted into a variety of somatic symptoms. These may include such symptoms as paralysis, pain, or loss of sensory function.

coping mechanisms Ways of adjusting to environmental stress without altering one's goals or purposes; includes both conscious and unconscious mechanisms.

coprophagia Eating of filth or feces.

counterphobia Deliberately seeking out and exposing onself to, rather than avoiding, the object or situation that is consciously or unconsciously feared.

countertransference The therapist's emotional reactions to the patient that are based on the therapist's unconscious needs and conflicts, as distinguished from his or her conscious responses to the patient's behavior. Countertransference may interfere with the therapist's ability to understand the patient and may adversely affect the therapeutic technique. Currently, there is emphasis on the positive aspects of countertransference and its use as a guide to a more empathic understanding of the patient.

cretinism A type of mental retardation and bodily malformation caused by severe, uncorrected thyroid deficiency in infancy and early childhood.

cri du chat A type of mental retardation. The name is derived from a catlike cry emitted by children with this disorder, which is caused by partial deletion of chromosome 5.

conversion symptom A loss of, or alteration in, voluntary motor or sensory functioning suggesting a neurological or general medical condition. Psychological factors are judged to be associated with the development of the symptom, and the symptom is not fully explained by a neurological or general medical condition or the direct effects of a substance. The symptom is not intentionally produced or feigned and is not culturally sanctioned.

culture-specific syndromes Forms of disturbed behavior specific to certain cultural systems that do not conform to western nosologic entities. Some commonly cited syndromes are the following: amok; koro; latah; piblokto, and windigo.

D

Da Costa's syndrome Neurocirculatory asthenia; "soldier's heart"; a functional disorder of the circulatory system that is usually a part of an anxiety state or secondary to hyperventilation.

decompensation The deterioration of existing defenses, leading to an exacerbation of pathological behavior.

defense mechanism Automatic psychological process that protects the individual against anxiety and from awareness of internal or external stressors or dangers. Defense mechanisms mediate the individual's reaction to emotional conflicts and to external stressors. Some defense mechanisms (e.g., projection, splitting, and acting out) are almost invariably maladaptive. Others, such as suppression and denial, may be either maladaptive or adaptive, depending on their severity, their inflexibility, and the context in which they occur.

déjà vu A paramnesia consisting of the sensation or illusion that one is seeing what one has seen before

delusion A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everyone else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary. The belief is not one ordinarily accepted by other members of the person's culture or subculture (e.g., it is not an article of religious faith). When a false belief involves a value judgment, it is regarded as a delusion only when the judgment is so extreme as to defy credibility. Delusional conviction occurs on a continuum and can sometimes be inferred from an individual's behavior. It is often difficult to distinguish between a delusion and an overvalued idea (in which case the individual has an unreasonable belief or idea but does not hold it as firmly as is the case with a delusion). Delusions are subdivided according to their content. Some of the more common types are: bizarre; delusional jealousy; grandiose; delusion of reference; persecutory; somatic; thought broadcasting; thought insertion.

delusional jealousy The delusion that one's sexual partner is unfaithful. erotomanic A delusion that another person, usually of higher status, is in love with the individual.

delusion of reference A delusion whose theme is that events, objects, or other persons in one's immediate environment have a particular and unusual significance. These delusions are usually of a negative or pejorative nature, but also may be grandiose in content. This differs from an idea of reference, in which the false belief is not as firmly held nor as fully organized into a true belief.

denial A defense mechanism where certain information is not accessed by the conscious mind. Denial is related to repression, a similar defense mechanism, but denial is more pronounced or intense. Denial involves some impairment of reality. Denial would be operating (as an example) if a cardiac patient who has been warned about the potential fatal outcome of engaging in heavy work, decides to start building a wall of heavy stones.

depersonalization An alteration in the perception or experience of the self so that one feels detached from, and as if one is an outside observer of, one's mental processes or body (e.g., feeling like one is in a dream).

derailment ("loosening of associations") A pattern of speech in which a person's ideas slip off one track onto another that is completely unrelated or only obliquely related. In moving from one sentence or clause to another, the person shifts the topic idiosyncratically from one frame of reference to another and things may be said in juxtaposition that lack a meaningful relationship. This disturbance occurs between clauses, in contrast to incoherence, in which the disturbance is within clauses. An occasional change of topic without warning or obvious connection does not constitute derailment.

derealization An alteration in the perception or experience of the external world so that it seems strange or unreal (e.g., people may seem unfamiliar or mechanical).

dereistic Mental activity that is not in accordance with reality, logic, or experience.

detachment A behavior pattern characterized by general aloofness in interpersonal contact; may include intellectualization, denial, and superficiality.

diplopia Double vision due to paralysis of the ocular muscles; seen in inhalant intoxication and other conditions affecting the oculomotor nerve.

disconnection syndrome Term coined by Norman Geschwind (1926¾1984) to describe the interruption of information transferred from one brain region to another.

disinhibition Freedom to act according to one's inner drives or feelings, with less regard for restraints imposed by cultural norms or one's superego; removal of an inhibitory, constraining, or limiting influence, as in the escape from higher cortical control in neurologic injury, or in uncontrolled firing of impulses, as when a drug interferes with the usual limiting or inhibiting action of GABA within the central nervous system.

disorientation Confusion about the time of day, date, or season (time), where one is (place), or who one is (person).

dysphoric mood An unpleasant mood, such as sadness, anxiety, or irritability.

displacement A defense mechanism, operating unconsciously, in which emotions, ideas, or wishes are transferred from their original object to a more acceptable substitute; often used to allay anxiety.

dissociation A disruption in the usually integrated functions of consciousness, memory, identity, or perception of the environment. The disturbance may be sudden or gradual, transient or chronic.

distractibility The inability to maintain attention, that is, the shifting from one area or topic to another with minimal provocation, or attention being drawn too frequently to unimportant or irrelevant external stimuli.

double bind Interaction in which one person demands a response to a message containing mutually contradictory signals, while the other person is unable either to comment on the incongruity or to escape from the situation.

drive Basic urge, instinct, motivation; a term used to avoid confusion with the more purely biological concept of instinct.

dyad A two-person relationship, such as the therapeutic relationship between doctor and patient in individual psychotherapy.

dysarthria Imperfect articulation of speech due to disturbances of muscular control or incoordination.

dysgeusia Perversion of the sense of taste.

dyskinesia Distortion of voluntary movements with involuntary muscular activity.

dyslexia Inability or difficulty in reading, including word-blindness and a tendency to reverse letters and words in reading and writing.

dyssomnia Primary disorders of sleep or wakefulness characterized by insomnia or hypersomnia as the major presenting symptom. Dyssomnias are disorders of the amount, quality, or timing of sleep.

dystonia Disordered tonicity of muscles.

E 

echolalia The pathological, parrotlike, and apparently senseless repetition (echoing) of a word or phrase just spoken by another person. echolalia Parrot-like repetition of overheard words or fragments of speech.

echopraxia Repetition by imitation of the movements of another. The action is not a willed or voluntary one and has a semiautomatic and uncontrollable quality.

ego In psychoanalytic theory, one of the three major divisions in the model of the psychic apparatus, the others being the id and the superego. The ego represents the sum of certain mental mechanisms, such as perception and memory, and specific defense mechanisms. It serves to mediate between the demands of primitive instinctual drives (the id), of internalized parental and social prohibitions (the superego), and of reality. The compromises between these forces achieved by the ego tend to resolve intrapsychic conflict and serve an adaptive and executive function. Psychiatric usage of the term should not be confused with common usage, which connotes self-love or selfishness.

ego ideal The part of the personality that comprises the aims and goals for the self; usually refers to the conscious or unconscious emulation of significant figures with whom one has identified. The ego ideal emphasizes what one should be or do in contrast to what one should not be or not do.

ego-dystonic Referring to aspects of a person's behavior, thoughts, and attitudes that are viewed by the self as repugnant or inconsistent with the total personality.

eidetic image Unusually vivid and apparently exact mental image; may be a memory, fantasy, or dream.

elaboration An unconscious process consisting of expansion and embellishment of detail, especially with reference to a symbol or representation in a dream.

elevated mood An exaggerated feeling of well-being, or euphoria or elation. A person with elevated mood may describe feeling "high," "ecstatic," "on top of the world," or "up in the clouds."

engram A memory trace; a neurophysiological process that accounts for persistence of memory

epigenesis Originally from the Greek "epi" (on, upon, on top of) and "genesis" (origin); the theory that the embryo is not preformed in the ovum or the sperm, but that it develops gradually by the successive formation of new parts. The concept has been extended to other areas of medicine, with different shades of meaning. Some of the other meanings are as follows: 1. Any change in an organism that is due to outside influences rather than to genetically determined ones. 2. The occurrence of secondary symptoms as a result of disease. 3. Developmental factors, and specifically the gene-environment interactions, that contribute to development. 4. The appearance of new functions that are not predictable on the basis of knowledge of the part-processes that have been combined. 5. The appearance of specific features at each stage of development, such as the different goals and risks that Erikson described for the eight stages of human life (trust vs. mistrust, autonomy vs. doubt, etc.). The life cycle theory adheres to the epigenetic principle in that each stage of development is characterized by crises or challenges that must be satisfactorily resolved if development is to proceed normally.

ethnology A science that concerns itself with the division of human beings into races and their origin, distribution, relations, and characteristics.

euthymic Mood in the "normal" range, which implies the absence of depressed or elevated mood.

expansive mood Lack of restraint in expressing one's feelings, frequently with an overvaluation of one's significance or importance. irritable Easily annoyed and provoked to anger.

extinction The weakening of a reinforced operant response as a result of ceasing reinforcement. See also operant conditioning. Also, the elimination of a conditioned response by repeated presentations of a conditioned stimulus without the unconditioned stimulus. See also respondent conditioning.

extraversion A state in which attention and energies are largely directed outward from the self as opposed to inward toward the self, as in introversion.

F 

fantasy An imagined sequence of events or mental images (e.g., daydreams) that serves to express unconscious conflicts, to gratify unconscious wishes, or to prepare for anticipated future events.

flashback A recurrence of a memory, feeling, or perceptual experience from the past.

flat affect An affect type that indicates the absence of signs of affective expression.

flight of ideas A nearly continuous flow of accelerated speech with abrupt changes from topic to topic that are usually based on understandable associations, distracting stimuli, or plays on words. When severe, speech may be disorganized and incoherent.

flooding (implosion) A behavior therapy procedure for phobias and other problems involving maladaptive anxiety, in which anxiety producers are presented in intense forms, either in imagination or in real life. The presentations, which act as desensitizers, are continued until the stimuli no longer produce disabling anxiety.

folie à deux A shared psychotic disorder between 2 people, usually people who are mutually dependent upon each other.

formal thought disorder An inexact term referring to a disturbance in the form of thinking rather than to abnormality of content. See blocking; loosening of associations; poverty of speech.

formication The tactile hallucination or illusion that insects are crawling on the body or under the skin.

fragmentation Separation into different parts, or preventing their integration, or detaching one or more parts from the rest. A fear of fragmentation of the personality, also known as disintegration anxiety, is often observed in patients whenever they are exposed to repetitions of earlier experiences that interfered with development of the self. This fear may be expressed as feelings of falling apart, as a loss of identity, or as a fear of impending loss of one's vitality and of psychological depletion.

free association In psychoanalytic therapy, spontaneous, uncensored verbalization by the patient of whatever comes to mind.

frotteurism One of the paraphilias, consisting of recurrent, intense sexual urges involving touching and rubbing against a nonconsenting person; common sites in which such activities take place are crowded trains, buses, and elevators. Fondling the victim may be part of the condition and is called toucherism.

fusion The union and integration of the instincts and drives so that they complement each other and help the organism to deal effectively with both internal needs and external demands.

G 

Gegenhalten "Active" resistance to passive movement of the extremities that does not appear to be under voluntary control.

globus hystericus The disturbing sensation of a lump in the throat.

glossolalia Gibberish-like speech or "speaking in tongues."

gender dysphoria A persistent aversion toward some or all of those physical characteristics or social roles that connote one's own biological sex.

gender identity A person's inner conviction of being male or female.

gender role Attitudes, patterns of behavior, and personality attributes defined by the culture in which the person lives as stereotypically "masculine" or "feminine" social roles.

grandiosity An inflated appraisal of one's worth, power, knowledge, importance, or identity. When extreme, grandiosity may be of delusional proportions.

grandiose delusion A delusion of inflated worth, power, knowledge, identity, or special relationship to a deity or famous person.

gustatory hallucination A hallucination involving the perception of taste (usually unpleasant).

H 

hallucination A sensory perception that has the compelling sense of reality of a true perception but that occurs without external stimulation of the relevant sensory organ. Hallucinations should be distinguished from illusions, in which an actual external stimulus is misperceived or misinterpreted. The person may or may not have insight into the fact that he or she is having a hallucination. One person with auditory hallucinations may recognize that he or she is having a false sensory experience, whereas another may be convinced that the source of the sensory experience has an independent physical reality. The term hallucination is not ordinarily applied to the false perceptions that occur during dreaming, while falling asleep (hypnagogic), or when awakening (hypnopompic). Transient hallucinatory experiences may occur in people without a mental disorder.

hedonism Pleasure-seeking behavior. Contrast with anhedonia.

5-HIAA (5-hydroxyindoleacetic acid) A major metabolite of serotonin, a biogenic amine found in the brain and other organs. Functional deficits of serotonin in the central nervous system have been implicated in certain types of major mood disorders, and particularly in suicide and impulsivity.

hippocampus Olfactory brain; a sea-horse¾shaped structure located within the brain that is an important part of the limbic system. The hippocampus is involved in some aspects of memory, in the control of the autonomic functions, and in emotional expression.

hyperacusis Inordinate sensitivity to sounds; it may be on an emotional or an organic basis.

hypersomnia Excessive sleepiness, as evidenced by prolonged nocturnal sleep, difficulty maintaining an alert awake state during the day, or undesired daytime sleep episodes. ideas of reference The feeling that casual incidents and external events have a particular and unusual meaning that is specific to the person. This is to be distinguished from a delusion of reference, in which there is a belief that is held with delusional conviction

hypnagogic Referring to the semiconscious state immediately preceding sleep; may include hallucinations that are of no pathological significance.

hypnopompic Referring to the state immediately preceding awakening; may include hallucinations that are of no pathological significance.

I 

id In Freudian theory, the part of the personality that is the unconscious source of unstructured desires and drives. See also ego; superego.

idealization A mental mechanism in which the person attributes exaggeratedly positive qualities to the self or others.

ideas of reference Incorrect interpretations of casual incidents and external events as having direct reference to oneself. May reach sufficient intensity to constitute delusions.

identification A defense mechanism, operating unconsciously, by which one patterns oneself after some other person. Identification plays a major role in the development of one's personality and specifically of the superego. To be differentiated from imitation or role modeling, which is a conscious process.

idiot savant A person with gross mental retardation who nonetheless is capable of performing certain remarkable feats in sharply circumscribed intellectual areas, such as calendar calculation or puzzle solving.

illusion A misperception or misinterpretation of a real external stimulus, such as hearing the rustling of leaves as the sound of voices. See also hallucination.

imprinting A term in ethology referring to a process similar to rapid learning or behavioral patterning that occurs at critical points in very early stages of animal development. The extent to which imprinting occurs in human development has not been established.

inappropriate affect An affect type that represents an unusual affective expression that does not match with the content of what is being said or thought.

incoherence Speech or thinking that is essentially incomprehensible to others because words or phrases are joined together without a logical or meaningful connection. This disturbance occurs within clauses, in contrast to derailment, in which the disturbance is between clauses. This has sometimes been referred to as "word salad" to convey the degree of linguistic disorganization. Mildly ungrammatical constructions or idiomatic usages characteristic of particular regional or cultural backgrounds, lack of education, or low intelligence should not be considered incoherence. The term is generally not applied when there is evidence that the disturbance in speech is due to an aphasia.

incorporation A primitive defense mechanism, operating unconsciously, in which the psychic representation of a person, or parts of the person, is figuratively ingested.

individuation A process of differentiation, the end result of which is development of the individual personality that is separate and distinct from all others.

indoleamine One of a group of biogenic amines (e.g., serotonin) that contains a five-membered, nitrogen-containing indole ring and an amine group within its chemical structure. inhibition Behavioral evidence of an unconscious defense against forbidden instinctual drives; may interfere with or restrict specific activities.

insomnia A subjective complaint of difficulty falling or staying asleep or poor sleep quality. Types of insomnia include:

initial insomnia Difficulty in falling asleep.

instinct An inborn drive. The primary human instincts include self-preservation, sexuality, and according to some proponents the death instinct, of which aggression is one manifestation.

integration The useful organization and incorporation of both new and old data, experience, and emotional capacities into the personality. Also refers to the organization and amalgamation of functions at various levels of psychosexual development.

intellectualization A mental mechanism in which the person engages in excessive abstract thinking to avoid confrontation with conflicts or disturbing feelings.

intersex condition A condition in which an individual shows intermingling, in various degrees, of the characteristics of each sex, including physical form, reproductive organs, and sexual behavior.

introspection Self-observation; examination of one's feelings, often as a result of psychotherapy.

introversion Preoccupation with oneself and accompanying reduction of interest in the outside world. Contrast to extraversion.

isolation A defense mechanism operating unconsciously central to obsessive-compulsive phenomena in which the affect is detached from an idea and rendered unconscious, leaving the conscious idea colorless and emotionally neutral.

K

Klinefelter's syndrome Chromosomal defect in males in which there is an extra X chromosome; manifestations may include underdeveloped testes, physical feminization, sterility, and mental retardation.

koro  A culture specific syndrome of China involving fear of retraction of penis into abdomen with the belief that this will lead to death.

L

la belle indifférence Literally, "beautiful indifference." Seen in certain patients with conversion disorders who show an inappropriate lack of concern about their disabilities. labile Rapidly shifting (as applied to emotions); unstable.

labile affect An affect type that indicates abnormal sudden rapid shifts in affect.

latah A culture specific syndrome of Southeast Asia involving startle-induced disorganization, hypersuggestibility, automatic obedience, and echopraxia.

latent content The hidden (i.e., unconscious) meaning of thoughts or actions, especially in dreams or fantasies. In dreams, it is expressed in distorted, disguised, condensed, and symbolic form.

learned helplessness A condition in which a person attempts to establish and maintain contact with another by adopting a helpless, powerless stance.

lethologica Temporary inability to remember a proper noun or name.

libido The psychic drive or energy usually associated with the sexual instinct. (Sexual is used here in the broad sense to include pleasure and love-object seeking.)

locus coeruleus A small area in the brain stem containing norepinephrine neurons that is considered to be a key brain center for anxiety and fear.

long-term memory The final phase of memory in which information storage may last from hours to a lifetime.

loosening of associations A disturbance of thinking shown by speech in which ideas shift from one subject to another that is unrelated or minimally related to the first. Statements that lack a meaningful relationship may be juxtaposed, or speech may shift suddenly from one frame of reference to another. The speaker gives no indication of being aware of the disconnectedness, contradictions, or illogicality of speech.

M 

macropsia The visual perception that objects are larger than they actually are.

magical thinking A conviction that thinking equates with doing. Occurs in dreams in children, in primitive peoples, and in patients under a variety of conditions. Characterized by lack of realistic relationship between cause and effect.

manifest content The remembered content of a dream or fantasy, as contrasted with latent content, which is concealed and distorted.

masochism Pleasure derived from physical or psychological pain inflicted on oneself either by oneself or by others. It is called sexual masochism and classified as a paraphilia when it is consciously sought as a part of the sexual act or as a prerequisite to sexual gratification. It is the converse of sadism, although the two tend to coexist in the same person.

memory consolidation The physical and psychological changes that take place as the brain organizes and restructures information that may become a permanent part of memory.

mental retardation A major group of disorders of infancy, childhood, or adolescence characterized by intellectual functioning that is significantly below average (IQ of 70 or below), manifested before the age of 18 by impaired adaptive functioning (below expected performance for age in such areas as social or daily living skills, communication, and self-sufficiency). Different levels of severity are recognized: an IQ level of 50/55 to 70 is Mild; an IQ level of 35/40 to 50/55 is Moderate; an IQ level of 20/25 to 35/40 is Severe; an IQ level below 20/25 is Profound.

MHPG (3-methoxy-4-hydroxyphenylglycol) A major metabolite of brain norepinephrine excreted in urine.

magical thinking The erroneous belief that one's thoughts, words, or actions will cause or prevent a specific outcome in some way that defies commonly understood laws of cause and effect. Magical thinking may be a part of normal child development.

micropsia The visual perception that objects are smaller than they actually are.

middle insomnia Awakening in the middle of the night followed by eventually falling back to sleep, but with difficulty.

mirroring 1) The empathic responsiveness of the parent to the developing child's grandiose-exhibitionistic needs. Parental expressions of delight in the child's activities signal that the child's wishes and experiences are accepted as legitimate. This teaches the child which of his or her potential qualities are most highly esteemed and valued. Mirroring validates the child as to who he or she is and affirms his or her worth. The process transforms archaic aims to realizable aims, and it determines in part the content of the self-assessing, self-monitoring functions and their relationships to the rest of the personality. The content of the superego is the residue of the mirroring experience. 2) A technique in psychodrama in which another person in the group plays the role of the patient, who watches the enactment as if gazing into a mirror. The first person may exaggerate one or more aspects of the patient's behavior. Following the portrayal, the patient is usually encouraged to comment on what he or she has observed.

mood A pervasive and sustained emotion that colors the perception of the world. Common examples of mood include depression, elation, anger, and anxiety. In contrast to affect, which refers to more fluctuating changes in emotional "weather," mood refers to a more pervasive and sustained emotional "climate."  Types of mood include: dysphoric, elevated, euthymic, expansive, irritable.

mood-congruent psychotic features Delusions or hallucinations whose content is entirely consistent with the typical themes of a depressed or manic mood. If the mood is depressed, the content of the delusions or hallucinations would involve themes of personal inadequacy, guilt, disease, death, nihilism, or deserved punishment. The content of the delusion may include themes of persecution if these are based on self-derogatory~ concepts such as deserved punishment. If the mood is manic, the content of the delusions or hallucinations would involve themes of inflated worth, power, knowledge, or identity, or a special relationship to a deity or a famous person. The content of the delusion may include themes of persecution if these are based on concepts such as inflated worth or deserved punishment.

mood-incongruent psychotic features Delusions or hallucinations whose content is not consistent with the typical themes of a depressed or manic mood. In the case of depression, the delusions or hallucinations would not involve themes of personal inadequacy, guilt, disease, death, nihilism, or deserved punishment. In the case of mania, the delusions or hallucinations would not involve themes of inflated worth, power, knowledge, or identity, or a special relationship to a deity or a famous person. Examples of mood-incongruent psychotic features include persecutory delusions (without self-derogatory~ or grandiose content), thought insertion, thought broadcasting, and delusions of being controlled whose content has no apparent relationship to any of the themes listed above.

N

negative symptoms Most commonly refers to a group of symptoms characteristic of schizophrenia that include loss of fluency and spontaneity of verbal expression, impaired ability to focus or sustain attention on a particular task, difficulty in initiating or following through on tasks, impaired ability to experience pleasure to form emotional attachment to others, and blunted affect.

negativism Opposition or resistance, either covert or overt, to outside suggestions or advice. May be seen in schizophrenia.

neologism In psychiatry, a new word or condensed combination of several words coined by a person to express a highly complex idea not readily understood by others; seen in schizophrenia and organic mental disorders.

neurotic disorder A mental disorder in which the predominant disturbance is a distressing symptom or group of symptoms that one considers unacceptable and alien to one's personality. There is no marked loss of reality testing ; behavior does not actively violate gross social norms, although it may be quite disabling. The disturbance is relatively enduring or recurrent without treatment and is not limited to a mild transitory reaction to stress. There is no demonstrable organic etiology.

nihilistic delusion The delusion of nonexistence of the self or part of the self, or of some object in external reality.

nystagmus Involuntary rhythmic movements of the eyes that consist of small-amplitude~ rapid tremors in one direction and a larger, slower, recurrent sweep in the opposite direction. Nystagmus may be horizontal, vertical, or rotary.

O

object relations The emotional bonds between one person and another, as contrasted with interest in and love for the self; usually described in terms of capacity for loving and reacting appropriately to others. Melanie Klein is generally credited with founding the British object-relations school.

obsession Recurrent and persistent thought, impulse, or image experienced as intrusive and distressing. Recognized as being excessive and unreasonable even though it is the product of one's mind. This thought, impulse, or image cannot be expunged by logic or reasoning.

oedipal stage Overlapping some with the phallic stage, this phase (ages 4 to 6) represents a time of inevitable conflict between the child and parents. The child must desexualize the relationship to both parents in order to retain affectionate kinship with both of them. The process is accomplished by the internalization of the images of both parents, thereby giving more definite shape to the child's personality. With this internalization largely completed, the regulation of self-esteem and moral behavior comes from within.

Oedipus complex Attachment of the child to the parent of the opposite sex, accompanied by envious and aggressive feelings toward the parent of the same sex. These feelings are largely repressed (i.e., made unconscious) because of the fear of displeasure or punishment by the parent of the same sex. In its original use, the term applied only to the boy or man.

olfactory hallucination A hallucination involving the perception of odor, such as of burning rubber or decaying fish.

ontogenetic Pertaining to the development of the individual.

operant conditioning (instrumental conditioning) A process by which the results of the person's behavior determine whether the behavior is more or less likely to occur in the future.

oral stage The earliest of the stages of infantile psychosexual development, lasting from birth to 12 months or longer. Usually subdivided into two stages: the oral erotic, relating to the pleasurable experience of sucking; and the oral sadistic, associated with aggressive biting. Both oral eroticism and sadism continue into adult life in disguised and sublimated forms, such as the character traits of demandingness or pessimism. Oral conflict, as a general and pervasive influence, might underlie the psychological determinants of addictive disorders, depression, and some functional psychotic disorders.

orientation Awareness of one's self in relation to time, place, and person.

overcompensation A conscious or unconscious process in which a real or imagined physical or psychological deficit generates exaggerated correction. Concept introduced by Adler.

overdetermination The concept of multiple unconscious causes of an emotional reaction or symptom.

overvalued idea An unreasonable and sustained belief that is maintained with less than delusional intensity (i.e., the person is able to acknowledge the possibility that the belief may not be true). The belief is not one that is ordinarily accepted by other members of the person's culture or subculture

P 

panic attacks Discrete periods of sudden onset of intense apprehension, fearfulness, or terror, often associated with feelings of impending doom. During these attacks there are symptoms such as shortness of breath or smothering sensations; palpitations, pounding heart, or accelerated heart rate; chest pain or discomfort; choking; and fear of going crazy or losing control. Panic attacks may be unexpected (uncued), in which the onset of the attack is not associated with a situational trigger and instead occurs "out of the blue"; situationally bound, in which the panic attack almost invariably occurs immediately on exposure to, or in anticipation of, a situational trigger ("cue"); and situationally predisposed, in which the panic attack is more likely to occur on exposure to a situational trigger but is not invariably associated with it.

paranoid ideation Ideation, of less than delusional proportions, involving suspiciousness or the belief that one is being harassed, persecuted, or unfairly treated.

parasomnia Abnormal behavior or physiological events occurring during sleep or sleep-wake transitions.

persecutory delusion  A delusion in which the central theme is that one (or someone to whom one is close) is being attacked, harassed, cheated, persecuted, or conspired against.

perseveration Tendency to emit the same verbal or motor response again and again to varied stimuli.

personality Enduring patterns of perceiving, relating to, and thinking about the environment and oneself. Personality traits are prominent aspects of personality that are exhibited in a wide range of important social and personal contexts. Only when personality traits are inflexible and maladaptive and cause either significant functional impairment or subjective distress do they constitute a Personality Disorder.

phallic stage The period, from about 21/2 to 6 years, during which sexual interest, curiosity, and pleasurable experience in boys center on the penis, and in girls, to a lesser extent, the clitoris.

phobia A persistent, irrational fear of a specific object, activity, or situation (the phobic stimulus) that results in a compelling desire to avoid it. This often leads either to avoidance of the phobic stimulus or to enduring it with dread.

piblokto  A culture specific syndrome of Eskimos involving attacks of screaming, crying, and running naked through the snow

preconscious Thoughts that are not in immediate awareness but that can be recalled by conscious effort.

pregenital In psychoanalysis, refers to the period of early childhood before the genitals have begun to exert the predominant influence in the organization or patterning of sexual behavior. Oral and anal influences predominate during this period.

pressured speech Speech that is increased in amount, accelerated, and difficult or impossible to interrupt. Usually it is also loud and emphatic. Frequently the person talks without any social stimulation and may continue to talk even though no one is listening.

prevalence Frequency of a disorder, used particularly in epidemiology to denote the total number of cases existing within a unit of population at a given time or over a specified period.

primary gain The relief from emotional conflict and the freedom from anxiety achieved by a defense mechanism. Contrast with secondary gain.

primary process In psychoanalytic theory, the generally unorganized mental activity characteristic of the unconscious. This activity is marked by the free discharge of energy and excitation without regard to the demands of environment, reality, or logic.

prodrome An early or premonitory sign or symptom of a disorder

projection A defense mechanism, operating unconsciously, in which what is emotionally unacceptable in the self is unconsciously rejected and attributed (projected) to others.

projective identification A term introduced by Melanie Klein to refer to the unconscious process of projection of one or more parts of the self or of the internal object into another person (such as the mother). What is projected may be an intolerable, painful, or dangerous part of the self or object (the bad object). It may also be a valued aspect of the self or object (the good object) that is projected into the other person for safekeeping. The other person is changed by the projection and is dealt with as though he or she is in fact characterized by the aspects of the self that have been projected.

projective tests Psychological diagnostic tests in which the test material is unstructured so that any response will reflect a projection of some aspect of the subject's underlying personality and psychopathology

prosopagnosia Inability to recognize familiar faces that is not explained by defective visual acuity or reduced consciousness or alertness.

pseudocyesis Included in DSM-IV as one of the somatoform disorders. It is characterized by a false belief of being pregnant and by the occurrence of signs of being pregnant, such as abdominal enlargement, breast engorgement, and labor pains.

pseudodementia A syndrome in which dementia is mimicked or caricatured by a functional psychiatric illness. Symptoms and response of mental status examination questions are similar to those found in verified cases of dementia. In pseudodementia, the chief diagnosis to be considered in the differential is depression in an older person vs. cognitive deterioration on the basis of organic brain disease.

psychomotor agitation Excessive motor activity associated with a feeling of inner tension. When severe, agitation may involve shouting and loud complaining. The activity is usually nonproductive and repetitious, and consists of such behavior as pacing, wringing of hands, and inability to sit still.

psychomotor retardation Visible generalized slowing of movements and speech.

psychosexual development A series of stages from infancy to adulthood, relatively fixed in time, determined by the interaction between a person's biological drives and the environment. With resolution of this interaction, a balanced, reality-oriented development takes place; with disturbance, fixation and conflict ensue. This disturbance may remain latent or give rise to characterological or behavioral disorders.

psychotic This term has historically received a number of different definitions, none of which has achieved universal acceptance. The narrowest definition of psychotic is restricted to delusions or prominent hallucinations, with the hallucinations occurring in the absence of insight into their pathological nature. A slightly less restrictive definition would also include prominent hallucinations that the individual realizes are hallucinatory experiences. Broader still is a definition that also includes other positive symptoms of Schizophrenia (i.e., disorganized speech, grossly disorganized or catatonic behavior). Unlike these definitions based on symptoms, the definition used in DSM-II and ICD-9 was probably far too inclusive and focused on the severity of functional impairment, so that a mental disorder was termed psychotic if it resulted in "impairment that grossly interferes with the capacity to meet ordinary demands of life." Finally, the term has been defined conceptually as a loss of ego boundaries or a gross impairment in reality testing. Based on their characteristic features, the different disorders in DSM-IV emphasize different aspects of the various definitions of psychotic.

psychotropic medication Medication that affects thought processes or feeling states.

R 

rationalization A defense mechanism, operating unconsciously, in which an individual attempts to justify or make consciously tolerable by plausible means, feelings or behavior that otherwise would be intolerable. Not to be confused with conscious evasion or dissimulation. See also projection.

reaction formation A defense mechanism, operating unconsciously, in which a person adopts affects, ideas, and behaviors that are the opposites of impulses harbored either consciously or unconsciously. For example, excessive moral zeal may be a reaction to strong but repressed asocial impulses.

reality principle In psychoanalytic theory, the concept that the pleasure principle, which represents the claims of instinctual wishes, is normally modified by the demands and requirements of the external world. In fact, the reality principle may still work on behalf of the pleasure principle but reflects compromises and allows for the postponement of gratification to a more appropriate time. The reality principle usually becomes more prominent in the course of development but may be weak in certain psychiatric illnesses and undergo strengthening during treatment. reality testing The ability to evaluate the external world objectively and to differentiate adequately between it and the internal world. Falsification of reality, as with massive denial or projection, indicates a severe disturbance of ego functioning and/or of the perceptual and memory processes upon which it is partly based.

reciprocal inhibition In behavior therapy, the hypothesis that if anxiety-provoking stimuli occur simultaneously with the inhibition of anxiety (e.g., relaxation), the bond between those stimuli and the anxiety will be weakened.

regression Partial or symbolic return to earlier patterns of reacting or thinking. Manifested in a wide variety of circumstances such as normal sleep, play, physical illness, and in many mental disorders.

reinforcement The strengthening of a response by reward or avoidance of punishment. This process is central in operant conditioning.

repetition compulsion In psychoanalytic theory, the impulse to reenact earlier emotional experiences. Considered by Freud to be more fundamental than the pleasure principle. Defined by Jones in the following way: "The blind impulse to repeat earlier experiences and situations quite irrespective of any advantage that doing so might bring from a pleasure-pain point of view."

repression A defense mechanism, operating unconsciously, that banishes unacceptable ideas, fantasies, affects, or impulses from consciousness or that keeps out of consciousness what has never been conscious. Although not subject to voluntary recall, the repressed material may emerge in disguised form. Often confused with the conscious mechanism of suppression. resistance One's conscious or unconscious psychological defense against bringing repressed (unconscious) thoughts into conscious awareness.

respondent conditioning (classical conditioning, Pavlovian conditioning) Elicitation of a response by a stimulus that normally does not elicit that response. The response is one that is mediated primarily by the autonomic nervous system (such as salivation or a change in heart rate). A previously neutral stimulus is repeatedly presented just before an unconditioned stimulus that normally elicits that response. When the response subsequently occurs in the presence of the previously neutral stimulus, it is called a conditioned response, and the previously neutral stimulus, a conditioned stimulus.

residual phase The phase of an illness that occurs after remission of the florid symptoms or the full syndrome.

S 

screen memory A consciously tolerable memory that serves as a cover for an associated memory that would be emotionally painful if recalled.

secondary gain The external gain derived from any illness, such as personal attention and service, monetary gains, disability benefits, and release from unpleasant responsibilities. See also primary gain.

secondary process In psychoanalytic theory, mental activity and thinking characteristic of the ego and influenced by the demands of the environment. Characterized by organization, systematization, intellectualization, and similar processes leading to logical thought and action in adult life. See also primary process; reality principle.

sensory extinction Failure to report sensory stimuli from one region if another region is stimulated simultaneously, even though when the region in question is stimulated by itself, the stimulus is correctly reported.

separation anxiety disorder A disorder with onset before the age of 18 consisting of inappropriate anxiety concerning separation from home or from persons to whom the child is attached. Among the symptoms that may be seen are unrealistic concern about harm befalling or loss of major attachment figures; refusal to go to school (school phobia) in order to stay at home and maintain contact with this figure; refusal to go to sleep unless close to this person; clinging; nightmares about the theme of separation; and development of physical symptoms or mood changes (apathy, depression) when separation occurs or is anticipated.

separation-individuation Psychological awareness of one's separateness, described by Margaret Mahler as a phase in the mother-child relationship that follows the symbiotic stage. In the separation-individuation stage, the child begins to perceive himself or herself as distinct from the mother and develops a sense of individual identity and an image of the self as object. Mahler described four subphases of the process: differentiation, practicing, rapprochement (i.e., active approach toward the mother, replacing the relative obliviousness to her that prevailed during the practicing period), and separation-individuation proper (i.e., awareness of discrete identity, separateness, and individuality).

sex A person's biological status as male, female, or uncertain. Depending on the circumstances, this determination may be based on the appearance of the external genitalia or on karyotyping.

sign An objective manifestation of a pathological condition. Signs are observed by the examiner rather than reported by the affected individual.

shaping Reinforcement of responses in the patient's repertoire that increasingly approximate sought-after behavior.

sick role An identity adopted by an individual as a "patient" that specifies a set of expected behaviors, usually dependent.

signal anxiety An ego mechanism that results in activation of defensive operations to protect the ego from being overwhelmed by an excess of excitement. The anxiety reaction that was originally experienced in a traumatic situation is reproduced in an attenuated form, allowing defenses to be mobilized before the current threat does, in fact, become overwhelming.

simultanagnosia Inability to comprehend more than one element of a visual scene at the same time or to integrate the parts into a whole

sleep terror disorder One of the parasomnias, characterized by panic and confusion when abruptly awakening from sleep. This usually begins with a scream and is accompanied by intense anxiety. The person is often confused and disoriented after awakening. No detailed dream is recalled, and there is amnesia for the episode. Sleep terrors typically occur during the first third of the major sleep episode.

social adaptation The ability to live and express oneself according to society's restrictions and cultural demands.

somatic delusion  A delusion whose main content pertains to the appearance or functioning of one's body.

somatic hallucination A hallucination involving the perception of a physical experience localized within the body (such as a feeling of electricity). A somatic hallucination is to be distinguished from physical sensations arising from an as-yet undiagnosed general medical condition, from hypochondriacal preoccupation with normal physical sensations, and from a tactile hallucination.

spatial agnosia Inability to recognize spatial relations; disordered spatial orientation.

splitting A mental mechanism in which the self or others are reviewed as all good or all bad, with failure to integrate the positive and negative qualities of self and others into cohesive images. Often the person alternately idealizes and devalues the same person.

stereotyped movements Repetitive, seemingly driven, and nonfunctional motor behavior (e.g., hand shaking or waving, body rocking, head banging, mouthing of objects, self-biting, picking at skin or body orifices, hitting one's own body).

Stockholm syndrome A kidnapping or terrorist hostage identifies with and has sympathy for his or her captors on whom he or she is dependent for survival.

stressor Any life event or life change that may be associated temporally (and perhaps causally) with the onset, occurrence, or exacerbation of a mental disorder.

structural theory Freud's model of the mental apparatus composed of id, ego, and superego.

stupor A state of unresponsiveness with immobility and mutism

sublimation A defense mechanism, operating unconsciously, by which instinctual drives, consciously unacceptable, are diverted into personally and socially acceptable channels.

substitution A defense mechanism, operating unconsciously, by which an unattainable or unacceptable goal, emotion, or object is replaced by one that is more attainable or acceptable.

suggestibility Uncritical compliance or acceptance of an idea, belief, or attribute.

suggestion The process of influencing a patient to accept an idea, belief, or attitude suggested by the therapist.

superego In psychoanalytic theory, that part of the personality structure associated with ethics, standards, and self-criticism. It is formed by identification with important and esteemed persons in early life, particularly parents. The supposed or actual wishes of these significant persons are taken over as part of the child's own standards to help form the conscience.

suppression The conscious effort to control and conceal unacceptable impulses, thoughts, feelings, or acts.

symbiosis A mutually reinforcing relationship between two persons who are dependent on each other; a normal characteristic of the relationship between the mother and infant child. See separation-individuation

symbolization A general mechanism in all human thinking by which some mental representation comes to stand for some other thing, class of things, or attribute of something. This mechanism underlies dream formation and some symptoms, such as conversion reactions, obsessions, and compulsions. The link between the latent meaning of the symptom and the symbol is usually

symptom A subjective manifestation of a pathological condition. Symptoms are reported by the affected individual rather than observed by the examiner.

syndrome A grouping of signs and symptoms, based on their frequent co-occurrence, that may suggest a common underlying pathogenesis, course, familial pattern, or treatment selection.

synesthesia A condition in which a sensory experience associated with one modality occurs when another modality is stimulated, for example, a sound produces the sensation of a particular color.

syntaxic mode The mode of perception that forms whole, logical, coherent pictures of reality that can be validated by others.

systematic desensitization A behavior therapy procedure widely used to modify behaviors associated with phobias. The procedure involves the construction of a hierarchy of anxiety-producing stimuli by the subject, and gradual presentation of the stimuli until they no longer produce anxiety.

T 

tactile hallucination A hallucination involving the perception of being touched or of something being under one's skin. The most common tactile hallucinations are the sensation of electric shocks and formication (the sensation of something creeping or crawling on or under the skin).

tangentiality Replying to a question in an oblique or irrelevant way. Compare with circumstantiality.

temperament Constitutional predisposition to react in a particular way to stimuli.

terminal insomnia Awakening before one's usual waking time and being unable to return to sleep.

termination The act of ending or concluding. In psychotherapy, termination refers to the mutual agreement between patient and therapist to bring therapy to an end. The idea of termination often occurs to both, but usually it is the therapist who introduces the subject into the session as a possibility to be considered. In psychoanalytic treatment, the patient's reactions are worked through to completion before the treatment ends. The early termination that is characteristic of focal psychotherapy and other forms of brief psychotherapy often requires more extensive work with the feelings of loss and separation.

therapeutic community A term of British origin, now widely used, for a specially structured mental hospital milieu that encourages patients to function within the range of social norms.

therapeutic window A well-defined range of blood levels associated with optimal clinical response to antidepressant drugs, such as nortriptyline. Levels above or below that range are associated with a poor response.

thought broadcasting The delusion that one's thoughts are being broadcast out loud so that they can be perceived by others.

thought insertion The delusion that certain of one's thoughts are not one's own, but rather are inserted into one's mind.

tic An involuntary, sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalization.

token economy A system involving the application of the principles and procedures of operant conditioning to the management of a social setting such as a ward, classroom, or halfway house. Tokens are given contingent on completion of specified activities and are exchangeable for goods or privileges desired by the patient.

tolerance A characteristic of substance dependence that may be shown by the need for markedly increased amounts of the substance to achieve intoxication or the desired effect, by markedly diminished effect with continued use of the same amount of the substance, or by adequate functioning despite doses or blood levels of the substance that would be expected to produce significant impairment in a casual user.

transference The unconscious assignment to others of feelings and attitudes that were originally associated with important figures (parents, siblings, etc.) in one's early life. The transference relationship follows the pattern of its prototype. The psychiatrist utilizes this phenomenon as a therapeutic tool to help the patient understand emotional problems and their origins. In the patient-physician relationship, the transference may be negative (hostile) or positive (affectionate). See also countertransference.

transitional object An object, other than the mother, selected by an infant between 4 and 18 months of age for self-soothing and anxiety-reduction. Examples are a "security blanket" or a toy that helps the infant go to sleep. The transitional object provides an opportunity to master external objects and promotes the differentiation of self from outer world.

transsexualism Severe gender dysphoria, coupled with a persistent desire for the physical characteristics and social roles that connote the opposite biological sex.

transvestism Sexual pleasure derived from dressing or masquerading in the clothing of the opposite sex, with the strong wish to appear as a member of the opposite sex. The sexual origins of transvestism may be unconscious.

trichotillomania The pulling out of one's own hair to the point that it is noticeable and causing significant distress or impairment.

U 

unconscious That part of the mind or mental functioning of which the content is only rarely subject to awareness. It is a repository for data that have never been conscious (primary repression) or that may have been conscious and are later repressed (secondary repression).

undoing A mental mechanism consisting of behavior that symbolically atones for, makes amends for, or reverses previous thoughts, feelings, or actions.

urophilia One of the paraphilias, characterized by marked distress over, or acting on, sexual urges that involve urine.

V

verbigeration Stereotyped and seemingly meaningless repetition of words or sentences.

visual hallucination A hallucination involving sight, which may consist of formed images, such as of people, or of unformed images, such as flashes of light. Visual hallucinations should be distinguished from illusions, which are misperceptions of real external stimuli.

voyeurism Peeping; one of the paraphilias, characterized by marked distress over, or acting on, urges to observe unsuspecting people, usually strangers, who are naked or in the process of disrobing, or who are engaging in sexual activity.

W

Wernicke's aphasia Loss of the ability to comprehend language coupled with production of inappropriate language.

windigo A culture specific syndrome of Canadians involving delusions of being possessed by a cannibal-istic monster (windigo), attacks of agitated depression, oral sadistic fears and impulses.

word salad A mixture of words and phrases that lack comprehensive meaning or logical coherence; commonly seen in schizophrenic states.

Z 

zeitgeist The general intellectual and cultural climate of taste characteristic of an era.

zoophilia One of the paraphilias, characterized by marked distress over, or acting on, urges to indulge in sexual activity that involves animals.

 

ที่มา : JOHN F. ABESS, M.D.
GLOSSARY  Terms in the field of Psychiatry and Neurology

http://www.abess.com/glossary.html

Asymmetric division Generation of distinct fates in progeny from a

single mitosis. Oriented division may position daughter cells in different

microenvironments or intrinsic determinants may be segregated into only

one daughter. Observed in some but not all stem cells and can occur in

other types of progenitor cell.

Cancer cell of origin Precancerous cell that gives rise to a cancer stem cell.

May be a mutated stem cell, or a committed progenitor that has acquired

self-renewal capacity through mutation.

Cancer-initiating cell General term that encompasses both cancer cell of

origin and cancer stem cell.

Cancer stem cell Self-renewing cell responsible for sustaining a cancer

and for producing differentiated progeny that form the bulk of the cancer.

Cancer stem cells identified in leukaemias and certain solid tumours are

critical therapeutic targets.

Cell replacement therapy Reconstitution of tissue by functional

incorporation of transplanted stem-cell progeny. Distinct from ‘bystander’

trophic, anti-inflammatory or immunomodulatory effects of introduced cells.

Clonal analysis Investigation of properties of single cells. Essential for

formal demonstration of self-renewal and potency.

Commitment Engaging in a programme leading to differentiation. For a

stem cell, this means exit from self-renewal.

Embryonic stem cell Pluripotent stem-cell lines derived from early

embryos before formation of the tissue germ layers.

Founder/ancestor/precursor cell General terms for cell without selfrenewal

ability that contributes to tissue formation. In some cases they

generate tissue stem cells.

Immortal strand The hypothesis of selective retention of parental DNA

strands during asymmetric self-renewal. Potential mechanism to protect

stem cells from the mutations associated with replication.

In vitro stem cell Self-renewal ex vivo in cells that do not overtly behave

as stem cells in vivo. Occurs due to liberation from inductive commitment

signals or by creation of a synthetic stem-cell state.

Label-retaining cell Candidate for adult tissue stem cell because of slow

division rate and/or immortal strand retention. Interpret with caution.

Lineage priming Promiscuous expression in stem cells of genes

associated with differentiation programmes.

Long-term reconstitution Lifelong renewal of tissue by transplanted cells.

The definitive assay for haematopoietic, epidermal and spermatogonial

stem cells. Transplantation assay may not be appropriate for all tissues.

Niche Cellular microenvironment providing support and stimuli necessary

to sustain self-renewal.

Plasticity Unproven notion that tissue stem cells may broaden potency in

response to physiological demands or insults.

Potency The range of commitment options available to a cell.

Totipotent Sufficient to form entire organism. Totipotency is seen in

zygote and plant meristem cells; not demonstrated for any vertebrate

stem cell.

Pluripotent Able to form all the body’s cell lineages, including germ

cells, and some or even all extraembryonic cell types. Example:

embryonic stem cells.

Multipotent Can form multiple lineages that constitute an entire

tissue or tissues. Example: haematopoietic stem cells.

Oligopotent Able to form two or more lineages within a tissue. Example:

a neural stem cell that can create a subset of neurons in the brain.

Unipotent Forms a single lineage. Example: spermatogonial

stem cells.

Progenitor cell Generic term for any dividing cell with the capacity to

differentiate. Includes putative stem cells in which self-renewal has not yet

been demonstrated.

Regenerative medicine Reconstruction of diseased or injured tissue by

activation of endogenous cells or by cell transplantation.

Reprogramming Increase in potency. Occurs naturally in regenerative

organisms (dedifferentiation). Induced experimentally in mammalian cells

by nuclear transfer, cell fusion, genetic manipulation or in vitro culture.

Self-renewal Cycles of division that repeatedly generate at least

one daughter equivalent to the mother cell with latent capacity for

differentiation. This is the defining property of stem cells.

Stem cell A cell that can continuously produce unaltered daughters and

also has the ability to produce daughter cells that have different, more

restricted properties.

Stem-cell homeostasis Persistence of tissue stem-cell pool throughout life.

Requires balancing symmetric self-renewal with differentiative divisions at

the population level, or sustained asymmetric self-renewal.

Stemness Unproven notion that different stem cells are regulated by

common genes and mechanisms.

Tissue stem cell Derived from, or resident in, a fetal or adult tissue, with

potency limited to cells of that tissue. These cells sustain turnover and

repair throughout life in some tissues.

Transit-amplifying cell Proliferative stem-cell progeny fated for

differentiation. Initially may not be committed and may retain self-renewal.

·ÕèÁÒ : NATURE|Vol 441|29 June 2006|doi:10.1038/nature04954