Exam 1
Terms
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- cocaine
- a drug of abuse, derived from the coca plant, that acts by potentiating catecholamine stimulation
- preganglionic
- "before the ganglion"; referring to neurons in the autonomic nervous system that run from the central nervous system to the autonomic ganglia
- postsynaptic potential
- also called graded potential or local potential; an electrical potential that is initiated at a postsynaptic site that can vary in amplitude and spreads passively across the cell membrane, decreasing in strength with time and distance
- endogenous ligand
- any substance, produced within the body, that selectively binds to the type of receptor that is under study
- epilepsy
- a brain disorder marked by major sudden changes in the electrophysiological state of the brain that are referred to as seizures
- dendritic spine
- an outgrowth along the dendrite of a neuron
- Sylvian fissure
- a deep fissure that demarcates the temporal lobe
- central sulcus
- a fissure that divides the frontal lobe from the parietal lobe
- pharmacokinetics
- collective name for all the factors that affect the movement of a drug into, through, and out of the body
- antipsychotics
- a class of drugs that alleviate schizophrenia
- refractory
- transiently inactivated or exhausted
- coronal plane
- the plane that divides the body into a front (anterior) and a back (posterio); also know as frontal plane or transverse plane
- electroencephalogram (EEG)
- a recording of gross electrical activity of the brain recorded from large electrodes places on the scalp
- mesolimbocortical pathway
- a set of dopaminergic axons arising in the midbrain and innervating the limbic system and cortex
- amine neurotransmitter
- a neurotransmitter based on modifications of a single amino acid nucleus, such as acetylcholine, serotonin, or dopamine
- globus pallidus
- one of the basal ganglia
- competitive ligand
- a substance that directly competes with the endogenous ligand for binding to a receptor molecule
- tricyclic antidepressents
- a class of drugs that act by increasing the synaptic accumulation of serotonin and norepinephrine
- endogenous opioids
- a family of peptide transmitters that have been called the body's own narcotics; the three kinds are enkephalins, endorphins, dynorphins
- mesostriatal pathway
- a set of dopaminergic axons arising from the midbrain and innervating the basal ganglia, including those from the substantia nigra to the striatum
- voltage-gated Na channel
- an Na-selective channel that open or closes in response to changes in the voltage of the local membrane potential; mediates the action potential
- nicotinic
- referring to cholinergic receptors that respond to nicotine as well as acetylcholine
- cholinergic
- referring to cells that use acetylcholine as their synaptic transmitter
- anxiolytics
- a class of substances that are used to combat anxiety
- postcentral gyrus
- the strip of parietal cortex, just behind the central sulcus, that receives somatosensory information from the entire body
- all-or-none property
- the face that the amplitude of the action potential is independent of the magnitude of the stimulus
- serotonin (5-HT)
- a synaptic transmitter that is produced in the raphe nuclei and is active in structures throughout the cerebral hemispheres
- depressents
- a class of drugs that act to reduce neural activity
- cholinergic
- referring to cells that use acetylcholine as their synaptic transmitter
- glial cells
- also called glia or neuroglia; nonneural brain cells that provide structural, nutritional, and other types of support to the brain
- hindbrain
- also called rhombencephalon; the rear division of the brain, which, in the mature vertebrate, contains the cerebellum, pons, and medulla
- axo-dendritic
- referring to a synapse in which a presynaptic axon terminal synapses onto a dendrite of the postsynaptic neuron, either via a dendritic spine or directly onto the dendrite itself
- seizure
- an epileptic episode
- opioid receptor
- a receptor that responds to endogenous and/or exogenous opiates
- event-related potential
- a large change in electrical potential in the brain that is elicited by a discrete sensory or motor event
- nitric oxide (NO)
- a soluble gas that serves as a retrograde gas neurotransmitter in the nervous system
- allocortex
- brain tissue with three layers or unlayered organization
- partial agonist/partial antagonist
- a drug that, when bound to a receptor, has less effect than the endogenous ligand would
- amygdala
- a group of nuclei in the medial anterior part of the temporal lobe
- glutamate
- an amino acid transmitter, the most common excitatory transmitter
- synaptic vesicle
- a small, spherical structure that contains molecules of synaptic transmitter
- lipid bilayer
- the structure of the neuronal cell membrane, which consists of two layers of lipid molecules, within which float various specialized proteins, such as receptors
- ventral tegmental area (VTA)
- a portion of the midbrain that projects dopaminergic fibers to the nucleus accumbens
- myelencephalon/medulla
- the caudal part of the hindbrain
- neuroleptics
- a class of antipsychotic drugs, traditionally dopamine receptor blockers
- temporal summation
- the summation of postsynaptic potentials that reach the axon hillock at different times; the closer in time that the potentials occur, the more complete the summation
- receptor subtype
- any type of receptor having functional characteristics that distinguish it from other types of receptors for the same neurotransmitters
- optical imaging
- a method for visualizing brain activity in which near-infrared light is passed through the scalp and skull
- curare
- an alkaloid neurotoxin that causes paralysis by blocking acetylcholine receptors in muscle
- substantia nigra
- a midbrain structure that provides dopaminergic projections to areas of the forebrain, especially the basal ganglia
- cocaine- and amphetamine-regulated transcript (CART)
- a peptide produced in the brain when an animal is injected either cocaine or amphetamine; associated with the appetite control circuitry of the hypothalamus
- autoreceptor
- a receptor for a synaptic transmitter that is located in the presynaptic membrane and tells the axon terminal how much transmitter has been released
- dendro-dendritic
- referring to a type of synapse in which a synaptic conncetion forms between the dendrites of two neurons
- axon hillock
- a cone-shaped area from which the axon originates out of the cell body
- pyramidal cell
- a type of large nerve cell that has a roughly pyramid-shaped cell body; found in the cerebral cortex
- channelopathy
- a genetic abnormality of ion channels, causing a variety of symptoms
- sodium-potassium pump
- the energetically expensive mechanism that pushes sodium ions out of a cell, and potassium ions in
- intracellular fluid
- also called cytoplasm; the watery solution found within cells
- gamma-aminobutyric acid (GABA)
- a widely distributed amino-acid transmitter, and the main inhibitory transmitter in the mammalian nervous system
- pons
- a portion of the metencephalon
- complex partial seizure
- in epilepsy, a type of seizure that doesn't involve the entire brain, and therefore can cause a wide variety of symptoms
- autoradiography
- a histological technique that shows the distribution of radioactive chemicals in tissues
- tolerance
- a condition in which, with repeated exposure to a drug, an individual becomes less responsive to a constant dose
- coccygeal
- referring to the lowest spinal vetebra (also known as the tailbone)
- metabolic tolerance
- the form of drug tolerance that arises when the metabolic machinery of the body becomes more efficient at clearing the drug, as a consequence of repeated exposure
- tetrahydrocannabinol (THC)
- the major active ingredient in marijuana
- reuptake
- the process by which released synaptic transmitter molecules are taken up and reused by the presynaptic neuron, thus stopping synaptic activity
- knee jerk reflex
- a variant of the stretch reflex in which stretching of the tendon beneath the knee leads to an upward kick of the leg
- neural chain
- a simple kind of neural circuit in which neurons are attached linearly, end to end
- lateral ventricle
- a complexly shaped lateral portion of the ventricular system within each hemisphere of the brain
- myelination
- the process of myelin formation
- vertebral arteries
- arteries that ascend the vertebrae, enter the base of the skull, and join together to form the basilar artery
- occiptal lobes
- large regions of cortex covering much of the posterior part of each cerebral hemisphere
- parallel fiber
- one of the axons of the granule cells that form the outermost layer of the cerebellar cortex
- dual dependence
- dependence for emergent drug effects that occur only when two drugs are taken simultaneously
- hippocampus
- a medial temporal lobe structure that is thought to be important for learning and memory
- raphe nuclei
- a string of nuclei in the midline of the midbrain and brainstem that contain most of the serotonergic neurons of the brain
- Nernst equation
- an equation used to calculate the equilibrium potential at a membrane
- ion channel
- a pore in the cell membrane that permits the passage of certain ions through the membrane when the channels are open
- heroin
- diacetylmorphine; an articially modified, very potent form of morphine
- output zone
- the part of the neuron, usually corresponding to the axon terminals, at which the cell's electrical activity is conveyed to another cell
- cerebrospinal fluid (CSF)
- the fluid that fills the cerebral ventricles
- conduction zone
- the part of the neuron over which the nerve's electrical signal may be actively propagated; usually corresponds to the cell's axon
- efferent
- to carry information away from a region of interest
- negative polarity
- a negative electrical-potential difference relative to a reference electrode
- noradrenergic
- referring to systems using norepinephrine (noradrenaline) as a transmitter
- cortical column
- one of the vertical columns that constitute that basic organization of the isocortex
- cingulate gyrus
- a cortical portion of the limbic system, found in the frontal and parietal midline
- ligand-gated ion channel
- an ion channel that opens or closes in response to the presnce of a particular chemical
- cerebral hemispheres
- the right and left halves of the brain
- temporal lobes
- large lateral cortical regions of each cerebral hemisphere, continuous with the parietal lobes posteriorly, and separated from the frontal lobe by the Sylvian fissure
- axonal transport
- the transportation of materials from the neuron cell body to distant regions in the dendrites and axons, and from the axon terminals back to the cell body
- anandamide
- an endogenous substance that binds the cannabinoid receptor molecule
- hallucinogens
- a class of drugs that alter sensory perception and produce peculiar experiences
- neuron or nerve cell
- the basic unit of the nervous system, each composed of a cell body, receptive extension(s) (dendrites), and a transmitting extension (axon)
- substance abuse
- a maladaptive pattern of substance use that has lasted more than a month but does not fully meet the criteria for dependence
- magnetoencephalohgraphy (MEG)
- a passive and noninvasive functional brain-imaging technique that measures the tiny magnetic fields produced by active neurons, in order to identify regions of the brain that are particularly active during a given task
- synapse
- a cellular location at which information is transmitted from one neuron to another
- neuron doctrine
- the hypothesis that the brain is composed of separate cells that are distinct structurally, metabolically, and functionally
- neural plasticity
- all called neuroplasticity; the ability of the nervous system to change in response to experience or the environment
- central nervous system (CNS)
- the portion of the nervous system that includes the brain and spinal cord
- calcium ion (Ca)
- a calcium atom that carries a double positive charge because it has lost two electrons
- diencephalon
- the posterior part of the forebrain, including the thalamus and hypothalamus
- microelectrode
- an especially small electrode used to record electrical potentials from living cells
- brainstem
- the region of the brain that consists of the midbrain, the pons, and the medulla
- biotransformation
- the process in which enzymes convert into a metabolite that is itself active, possibly in ways that are substantially different from the actions of the original substance
- Schwann cell
- the accessory cell that forms myelin in the peripheral nervous system
- MDMA
- also called ecstasy; a drug of abuse, 3,4-methylenedioxymethamphetamine
- mitochondrion
- a cellular organelle that provides metabolic energy for the cell's processes
- opium
- a heterogenous extract of the seedpod juice of the opium poppy
- anion
- a negatively charged ion, such as a protein or chloride ion
- nissl stain
- a histological stain that outlines all cell bodies because the dyes are attracted to RNA, which encircles the nucleus
- anterior cerebral arteries
- two large arteries, arising from the internal carotids, that provide blood to the anterior poles and medial surfaces of the cerebral hemispheres
- tract
- a bundle of axons found within the central nervous system
- electrostatic pressure
- the propensity of charges molecules or ions to move, via diffusion, toward areas with the opposite charge
- petit mal seizure
- also called an absence attack; a seizure that is characterized by a spike-and-wave EEG and often involves a loss of awareness and inability to recall events surrounding the seizure
- sensory neuron
- a neuron that is directly affected by changes in the environment, such as light, odor, or touch
- medial
- toward the middle
- node of Ranvier
- a gap between successive segments of the myelin sheath where the axon membrane is exposed
- angiogram
- a specialized x-ray image of the head, taken shortly after the cerebral blood vessels have been filled with a radiopaque dye by means of a catheter
- computerized axial tomography (CAT/CT)
- a noninvasive technique for examining brain structure in humans through computer analysis of x-ray absorption at several positions around the head
- axon collateral
- a branch of an axon from a single neuron
- co-localization
- also called co-release; here, the appearance of more than one neurotransmitter in a given presynaptic terminal
- electrical synapse
- also called gap junction; the region between neurons where the presynaptic and postsynaptic membranes are so close that the nerve impulse can jump to the postsynaptic membrane without first being translated into a chemical message
- motoneuron
- also called motor neuron; a nerve cell in the spinal cord that transmits motor messages from the spinal cord to the muscles
- excitatory postsynaptic potential (EPSP)
- a depolarizing potential in the postsynaptic neuron that is caused by excitatory presynaptic impulses; increase the probability that the postsynaptic neuron will fire an action potential
- afterpotential
- the positive or negative change in membrane potential that may follow an action potential
- fornix
- a fiber tract that extends from the hippocampus to the mammillary body
- innervate
- the provide neural input
- presynaptic
- referring to the region of the synapse that receives and responds to neurotransmitter
- positron emission tomography (PET)
- a technique for examining brain function by combining tomography with injection of radioactive substances used by the brain
- postganglionic
- "after the ganglion"; referring to neurons in the autonomic nervous system that run from the autonomic ganglia to various targets in the body
- grand mal seizure
- a type of generalized epileptic seizure in which nerve cells fire in high-frequency bursts
- c-fos
- an immediate early gene commonly used to identify activated neurons
- edema
- the swelling of tissue, especially in the brain, in response to injury
- ventral root
- the branch of a spinal nerve, arising from the ventral horn of the spinal cord, that carries motor messages from the spinal cord to the peripheral nervous system
- agonist
- a molecule, usually a drug, that binds a receptor molecule and initiates a response like that of another molecule, usually a neurotransmitter
- meninges
- the three protective sheets of tissue--dura mater, pia mater, and arachnoid--that surround the brain and spinal cord
- postsynaptic membrane
- the specialized membrane on the surface of the cell that receives information from a presynaptic neuron
- dedrite
- one of the extensions of the cell body that are the receptive surfaces of the neuron
- catecholamines
- a class of monoamines that serve as neurotransmitters, including dopamine and norepinephrine
- bioavailable
- referring to a substance, usually a drug, that is present in the body in a form that is able to interact with physiological mechanisms
- meningitis
- an acute inflammation of the meninges, usually caused by a viral or bacterial infection
- chloride ion (Cl)
- a chlorine atom that carries a negative charge because is has gained one electron
- action potential
- the propagated electrical message of a neuron that travels along the axon to the presynaptic axon terminals
- conduction velocity
- the speed at which an action potential is propagated along the length of an axon (or section of a peripheral nerve)
- acetylcholine (ACh)
- an amine transmitter that stimulates muscle contraction, but is also found throughout the brain
- immunocytochemistry (ICC)
- a method for detecting a particular protein in tissues in which (1) an antibody recognizes and binds to the protein and (2) chemical methods are then used to leave a visible reaction product around each antibody
- cue-induced drug use
- an increased likelihood to use a drug (especially an addictive drug) because of the presence of environmental stimuli that were present during previous use of the same drug
- opioid peptide
- a type of endogenous peptide that mimics the effects of morphine in binding to opioid receptors and producing marked analgesia and reward
- thalamus
- the brain regions that surround the third ventricle
- microglial cells
- also called microglia; extremely small glial cells that remove cellular debris from injured or dead cells
- granule cell
- a type of small nerve cell
- modulatory site
- a portion of a receptor that, when bound by a compound, alters the receptor's response to its transmitter
- diffusion
- the spontaneous spread of molecules of one substance among molecules of another substance until a uniform concentration is achieved
- dorsal
- toward or at the back
- multiple sclerosis
- literally "many scars"; a disorder characterized by widespread degeneration of myelin
- sacral
- referring to the 5 spinal segments that make up the lower part of the lower back
- potassium ion (K)
- a potassium atom that carries a positive charge because it has lost one electron
- horseradish peroxidase (HRP)
- an enzyme found in horseradish and other plants that is used to determine the cells of origin of a particular set of axons
- mammillary body
- one of a pair of nuclei at the base of the brain
- indoleamines
- a class of mono amines that serve as neurotransmitters, including serotonin and melatonin
- magnetic resonance imaging (MRI)
- a noninvasive technique that uses magnetic energy to generate images that reveal some structural details in the living brain
- sagittal plane
- the plane that bisects the body into right and left halves
- blood-brain barrier
- the mechanisms that make the movement of substances from capillaries into brain cells more difficult than affording the brain greater protection from exposure to some substances found in the blood
- sympathetic chain
- a chain of ganglia that runs along each side of the spinal column; part of the sympathetic nervous system
- tectum
- the dorsal portion of the midbrain, including the inferior and superior colliculi
- enteric nervous system
- an extensive meshlike system of neurons that governs the functioning of the gut
- striatum
- the caudate nucleus and putamen together
- gas neurotransmitter
- a soluble gas, such as nitric oxide or carbon monoxide, that is produced and released by a neuron to alter the funtioning of another neuron
- stroke
- damage to a region of brain tissue that results from blockage or rupture of vessels that supply blood to that region
- basal ganglia
- a group of forebrain nuclei found deep within the cerebral hemispheres
- parietal lobes
- large regions of cortex lying between the frontal and occipital lobes of each cerebral hemisphere
- kindling
- a method of experimentally inducing and epiletic seizure by repeatedly stimulating a brain region
- peptide neurotransmitter
- a neurotransmitter consisting of a short chain of amino acids
- aspartate
- an amino acid transmitter that is excitatory at many synapses
- autonomic ganglia
- collections of nerve cell bodies, belonging to the autonomic division of the peripheral nervous system, that are found in various locations and innervate the major organs
- reticular formation
- an extensive region of the brainstem (extending from the medulla through the thalamus) that is involved in arousal
- nucleus
- here, an anatomical collection of neurons within the central nervous system
- sensitization
- a process in which the body shows an enhanced response to a given drug after repeated doses
- sodium ion (Na)
- a sodium atom that carries a positive charge because it has lost one electron
- blood-brain barrier
- the mechanisms that make the movement of substances from capillaires into brain cells more difficult than exchanges in other body organs
- chemical neuroanatomy
- the distribution of key chemicals, such as transmitters and enzymes, within the structure of the nervous system
- nerve
- a collection of axons bundled together outside the central nervous system
- neurosteroids
- steroids produced in the brain
- monopolar neuron
- a nerve cell with a single branch that leaves the cell body and then extends in two directions: one end is the receptive pole, the other end the output zone
- analgesic
- referring to painkilling properties
- exogenous ligand
- any substance, originating from outside the body, that selectively binds to the type of receptor that is under study
- maximal response
- the strongest effect that a drug can have on a particular measured response, no matter how much of the drug is given
- dose-response curve (DRC)
- a formal plot of a drug's effects versus the dose given
- lateral interaction
- especially in sensory systems, the phenomenon by which reciprocal connections among neurons at the same level in the hierarchy more sharply tune the responses of the system
- atypical neuroleptics
- a class of antischizophremic drugs that have actions other than the dopamine D2 receptor antagonism that characterizes typical neuroleptics
- neurophysiology
- the study of the life processes of neurons
- gross neuroanatomy
- anatomical features of the nervous system that are apparent to the naked eye
- ketamine
- a dissociative anesthetic drug that acts as an NMDA receptor antagonist
- marijuana
- a dried preparation of the Cannabis sativa plant, usually smoked to obtain THC
- saltatory conduction
- the form of conduction that is characteristic of myelinated axons, in which the nerve impulse jumps from one node of Ranvier to the next
- sympathetic nervous system
- one of two systems that compose the autonomic nervous system; arises from the thoracic and lumbar spinal cord
- in situ hybridization
- a method for detecting particular RNA transcripts in tissue sections by providing a nucleotide probe that is complementary to, and will therefore hybridize with, the transcript of interest
- noncompetitive ligand
- a drug that affects a transmitter receptor while binding at a site other than that bound by the endogenous ligand
- corpus callosum
- the main band of axons that connect the two cerebral hemispheres
- inferior colliculi
- paired structures on the dorsal surface of the midbrain, caudal to the superior colliculi, that receive auditory information
- spinal nerve
- also called somatic nerve; a nerve that emerges from the spinal cord
- metencephalon
- a subdivision of the hindbrain that includes the cerebellum and pons
- oligodendrocyte
- a type of glial cell that is commonly associated with nerve cell bodies
- axo-axonic
- referring to a synapse in which a presynaptic axon terminal synapses onto another axon's terminal
- superior colliculi
- paired structures on the dorsal surface of the midbrain, rostral to the inferior colliculi, that receive visual information
- selective serotonin reuptake inhibitor (SSRI)
- a drug that blocks the reuptake of transmitter at serotonergic synapses
- pharmacodynamics
- collective name for the factors that affect the realtionship between a drug and its target receptors, such as affinity and efficacy
- olfactory bulb
- an anterior basal structure that receives olfactory (smell) inputs from nasal cavaties
- binding affinity
- the propensity of molecules of a drug (or other ligand) to bind to their corresponding receptors; drugs with high affinity for their receptors are effective even at low doses
- parasympathetic nervous system
- one of two systems that compose the autonomic nervous system; arises from both the cranial nerves and the sacral spinal cord
- antagonist
- a molecule, usually a drug, that interferes with or prevents the action of a transmitter
- neurotransmitter
- also simply called transmitter; the chemical, released from the presynaptic axon terminal, that serves as the basis of communication between neurons
- degradation
- the process by which neurotransmitter molecules are broken down into inactive metabolites
- saxitoxin (STX)
- an animal toxin that blocks sodium channels when applied to the outer surface of the cell membrane
- limbic system
- a loosely defined, widespread group of brain nuclei that innervate each other to form a network
- histology
- the study of tissue structure
- posterior/caudal
- the tail end of the body
- multipolar neuron
- a nerve cell that has many dendrites and a single axon
- benzodiazepine agonists
- a class of antianxiety drugs that bind to sites on GABAA receptors
- LD50
- lethal dose 50%; the dose of a drug at which half the treated animals will die
- dependence
- also called addiction; the strong desire to self-administer a drug of abuse
- allopreganolone
- a naturally occurring steroid that modulates GABA receptor activity in much the same way that benzodiazepine anxiolytics do
- typical neuroleptics
- a major class of antischizophrenic drugs that share an antagonist activity at dopamine D2 receptors
- nondirected synapse
- a type of synapse in which the presynaptic and postsynaptic cells are not in close apposition; instead, neurotransmitter is released by axonal varicosities and diffuses away to affect wide regions of tissue
- norepinephrine (NE)
- also called noradrenaline; a synaptic transmitter that is produced mainly in the brainstem nuclei
- circle of Willis
- a structure at the base of the brain that is formed by joining of the carotid and basilar arteries
- cervical
- referring to the topmost 8 segments of the spinal cord, in the neck region
- morphine
- an opiate compound derived from the poppy flower
- fetal alcohol syndrome (FAS)
- a disorder, including mental retardation and characteristic facial anomalies, that affects children exposed to too much alcohol (through materal ingestion) during fetal development
- relative refractory phase
- a period of reduced sensitivity during which only strong stimulation produces an action potential
- bungarotoxin
- a neurotoxin, isolated from the venom of the banded krait, that selective blocks acetylcholine receptors
- lateral
- toward the side
- synaptic delay
- the brief delay between the arrival of an action potential at the axon terminal and the creation of a postsynaptic potential
- adenosine
- in the context of neural transmission, a neuromodulator that alters synaptic activity
- ionotropic receptor
- a receptor protein that includes an ion channel that is opened when the receptor is bound by an appropriate ligand
- anterior/rostral
- the head end of the body
- extracellular fluid
- the fluid in the spaces between cells and in the vascular system
- caffeine
- a stimulant compound found in coffee, cacao, and other plants
- batrachotoxin
- a toxin, produced by poison arrow frogs, that selectively interferes with Na channels
- forebrain
- also call prosencephalon; the frontal division of the neural tube, containing the cerebral hemispheres, the thalamus, and the hypothalamus
- amino acid neurotransmitter
- a neurotransmitter that is itself an amino acid, such as GABA, glycine, or glutamate
- concentration gradient
- variation of the concentration of a substance within a region
- basal dendrite
- one of several dendrites on a pyramidal cell that extend horizontally from the cell body
- divergence
- the phenomenon of neural connections in which one cell sends signals to many other cells
- bipolar neuron
- a nerve cell that has a single dendrite at one end and a single axon at the other end
- functional tolerance
- decreased responding to a drug after repeated exposures, generally as a consequence of up- or down-regulation of receptors
- local potential
- an electrical potential that is initiated by stimulation at a specific site and spreads passively across the cell membrane, decreasing in strength with time and distance
- down-regulation
- a compensatory reduction in receptor availability at the synapses of a neuron
- ligand
- a substance that binds to receptor molecules, such as those at the surface of the cell
- axon terminal
- the end of an axon or axon collateral, which forms a synapse on a neuron or other target
- proximal
- near the trunk or center
- neural tube
- an embryonic structure with subdivisions that correspond to the future forebrain, midbrain, and hindbrain
- red nucleus
- a brainstem structure related to motor control
- synaptic cleft
- the space between the presynaptic and postsynaptic elements
- up-regulation
- a compensatory increase in receptor availability at the synapses of a neuron
- hypothalamus
- part of the diencephalon, lying ventral to the thalamus
- frontal lobe
- the most anterior portion of the cerebral cortex
- cerebellum
- a structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement
- nucleus accumbens
- a region of the forebrain that receives dopaminergic innervation from the ventral tegmental area
- G proteins
- a class of proteins that reside next to the intracellular portion of a receptor and that are activated when the receptor binds an appropriate ligand on the extracellular surface
- nicotine
- a compound found in plants, including tobacco, that acts as an agonist on a large class of cholinergic receptors
- hyperpolarization
- an increase in membrane potential (the interior of the neuron becomes even more negative)
- receptor
- also called receptor molecule; a protein that captures and reacts to molecules of a transmitter or hormone
- endocannabinoid
- an endogenous ligand of cannabinoid receptors; thus, an analog of marijuana that is produced by the brain
- contralateral
- relative to one location, a second location is on the opposite side of the body
- isocortex/cortex
- cerebral cortex that is made up of six distinct layers
- extracellular signal-regulated kinase (ERK)
- an important intracellular signal transduction system that can be activated by many different events that affect the cell surface
- antidepressents
- a class of drugs that relieve the symptoms of depression
- thoracic
- referring to the 12 spinal segments below the cervical (neck) portion of the spinal cord, corresponding to the chest
- ED50
- effective dose 50%; the dose of a drug that is required to produce half of its maximal effect
- neurochemistry
- the branch of neuroscience concerned with the fundamental chemical composition and processes of the nervous system
- integration zone
- the part of the neuron that initiates nerve activity if the sum of all inhibitory and excitatory postsynaptic potentials exceeds a threshold value; usually corresponds to the neuron's axon hillock
- fourth ventricle
- the passageway within the pons that receives cerebrospinal fluid from the third ventricle and release it to surround the brain and spinal cord
- caudate nucleus
- one of the basal ganglia; it has a long extension or tail
- pia mater
- the innermost of the three meninges that surround the brain and spinal cord
- serotonergic
- referring to neurons that use serotonin as their synaptic transmitter
- depolarization
- a reduction in membrane potential (the interior of the neuron becomes less negative)
- interneuron
- a neuron that is neither a sensory neuron nor a motoneuron; it receives input from and sends output to other neurons
- node of Ranvier
- a gap between successive segments of the myelin sheath where the axon membrane is exposed
- Purkinje cell
- a type of large nerve cell in the cerebellar cortex
- periaqueductal gray
- the neuronal body-rich region of the midbrain surrounding the cerebral aqueduct that connects the third and fourth ventricles
- metabotropic receptor
- a trype of transmitter receptor that does not contain an ion channel but may, when activated, use a G protein system to alter the functioning of the postsynaptic cell
- gyrus
- a ridged or raised portion of a convoluted brain surface
- inhibitory postsynaptic potential (IPSP)
- a hyperpolarizing potential in the postsynpatic neuron that is caused by inhibitory connections; decrease the probabilty that the postsynaptic neuron will fire an action potential
- immediate early genes (IEGs)
- a class of genes that show rapid but transient increases in expression in cells that have become activated
- transporters
- specialized receptors in the presynaptic membrane that recognize transmitter molecules and return them to the presynaptic neuron for reuse
- muscarinic
- referring to cholinergic receptors that respond to the chemical muscarine as well as acetylcholine
- axon hillock
- a cone-shaped area from which the axon originates out of the cell body; functionally, the integration zone of the neuron
- dura mater
- the outermost of the three meninges that surround the brain and spinal cord
- third ventricle
- the midline ventricle that conducts cerebrospinal fluid from the lateral ventricles to the fourth ventricle
- varicosity
- the axonal swelling from which neurotransmitter diffuses in a nondirected synapse
- ventricular system
- a system of fluid-filled cavaties inside the brain
- neuropharmacology
- also called psychopharmacology; the study of the effects of drugs on the nervous system and behavior
- apical dendrite
- the dendrite that extends from a pyramidal cell to the outermost surface of the cortex
- ion
- an atom or molecule that has acquired an electrical charge by gaining or losing one or more electrons
- cross-tolerance
- a condition in which the development of tolerance for an administered drug causes an individual to develop tolerance for another drug
- neuromodulator
- a substance that influences the activity of synaptic transmitters
- input zone
- the part of a neuron that receives information, from other neurons or from specialized sensory structures; usually corresponds to the cell's dendrites
- tetrodotoxin (TTX)
- a toxin from puffer fish ovaries that blacks the voltage-gated sodium channel, preventing action potential conduction
- graded response
- a membrane electrical potential that spreads passively across the cell membrane, decreasing in strength with time and distance
- orphan receptor
- any receptor for which no endogenous ligand has yet been discovered
- second messenger
- a slow-acting substance in the postsynaptic cell that amplifies the effects of synaptic activity and signals synaptic activity within the post-synaptic cell
- substantia nigra
- a brainstem structure in humans that is related to the basal ganglia and named for its dark pigmentation
- excitotoxicity
- the property by which neurons die when overstimulated, as with large amounts of glutamate
- orexins
- a group of proteins expressed in the lateral hypothalamus that trigger feeding and have been implicated in narcolepsy
- dorsal root
- the branch of a spinal nerve, entering the dorsal horn of the spinal cord, that carries sensory information from the peripheral nervous system to the spinal cord
- cation
- a positively charged ion, such as a potassium or sodium ion
- distal
- toward the end of a limb
- putamen
- one of the basal ganglia
- middle cerebral arteries
- two large arteries, arising from the internal carotids, that provide blood to most of the lateral surfaces of the cerebral hemispheres
- gray matter
- areas of the brain that are dominated by cell bodies and are devoid of myelin
- carotid arteries
- the major arteries that ascend the left and right sides of the neck to the brain
- locus coeruleus
- a small nucleus in the brainstem whose neurons produce norepinephrine and modulate large areas of the forebrain
- pinocytosis
- the process by which synaptic neurotransmitter is repackaged into synaptic vesicles
- arborization
- the elaborate branching of the dendrites of some neurons
- afferent
- to carry information into a region of interest
- threshold
- the stimulus intensity that is just adequate to trigger a nerve impulse at the axon hillock
- amphetamine
- a molecule that resembles the structure of the catecholamine transmitters and enhances their activity
- cell nucleus
- the spherical central structure of a cell that contains the chromosomes
- spatial summation
- the summation at the axon hillock of postsynaptic potentials from across the cell body; if this summation reaches threshold, an action potential is triggered
- glutamatergic
- referring to cells that use glutamate as their synaptic transmitter
- retrograde transmitter
- a neurotransmitter that diffuses from the postsynaptic neuron back to the presynaptic neuron
- midbrain
- also call mesencephalon; the middle division of the brain
- selective permeability
- the property of a membrane that allows some substances to pass through, but not others
- posterior cerebral arteries
- two large arteries, arising from the basilar artery, that provide blood to posterior aspects of the cerebral hemispheres, cerebellum, and brainstem
- ventral
- toward or at the belly or front
- cell membrane
- the lipid bilayer that ensheathes a cell
- resting membrane potential
- a difference in electrical potential across the membrane of a nerve cell during an inactive period
- choroid plexus
- a highly vascular portion of the lining of the ventricles that secretes cerebrospinal fluid
- astrocyte
- a star-shaped glial cell with numerous processes (extensions) that run in all directions
- aura
- in epilepsy, the unusual sensations or premonition that may precede the beginning of a seizure
- telecephalon
- the frontal subdivision of the forebrain that includes the cerebral hemispheres when fully developed
- dorsal raphe
- one of the midbrain nuclei that give rise to most of the serotonergic projections of the brain
- peripheral nervous system
- the portion of the nervous system that includes all the nerves and neurons outside the brain and spinal cord
- glycine
- an amino acid transmitter, often inhibitory
- cell body or soma
- the region of a neuron that is defined by the presence of the cell nucleus
- dopamine (DA)
- a monoamine transmitter found in the midbrain--especially the substantia nigra--and basal forebrain
- neurotransmitter
- also called synaptic transmitter, chemical transmitter, or simply transmitter; the chemical released from the presynaptic axon terminal, that serves as the basis of communication between neurons
- inverse agonist
- a substance that binds to a receptor and causes it to do the opposite of what the naturally occurring transmitter does
- receptor molecule
- also called receptor; a protein that captures and reacts to molecules of the transmitter or hormone
- cerebral cortex
- the outer covering of the cerebral hemispheres
- phencyclidine (PCP)
- also called angel dust; an anesthetic agent that is also a psychedelic drug
- ipsalateral
- relative to one location, a second location is on the same side of the body
- saturated
- referring to the condition in which a maximal number of receptors of one type have been bound by molecules of a drug; additional doses of drug cannot produce additional binding
- myelin
- the fatty insulation around an axon, formed by accessory cells, that improves the speed of conduction of nerve impulses
- absolute refractory phase
- a brief period of complete insensitivity to stimuli
- convergence
- the phenomenon of neural connections in which many cells send signals to a single cell
- transcranial magnetic stimulation (TMS)
- localized, noninvasive stimulation of cortical neurons through the application of strong magnetic fields
- monoamine oxidase inhibitor (MAOI)
- an antidepressent drug that blocks the breakdown of monoamine neurotransmitters by the enzyme monoamine oxidase, resulting in an accumulation of monamine transmitters in synapses
- postsynaptic
- referring to the region of a synapse that receives and responds to neurotransmitter
- golgi stain
- a histological stain that fills a small proportion of neurons with a dark, silver-based precipitate
- equilibrium
- in chemistry, the point at which all ongoing reactions are canceled or balanced by others, resulting in a stable, balanced, or unchanging system
- basilar artery
- an artery, formed by the fusion of the vertebral arteries, that supplies blood to the brainstem and to posterior portions of the cerebral hemispheres
- gated
- referring to the property by which an ion channel may be opened or closed by factors such as chemicals, voltage changes, or mechanical actions
- white matter
- a shiny layer underneath the cortex that consists largely of axons with white myelin sheaths
- axon
- a single extension from the nerve cell that carries nerve impulses from the cell body to other neurons
- millivolt (mV)
- one thousandth of a volt
- lumbar
- referring to the 5 spinal segments that make up the upper part of the lower back
- cranial nerve
- a nerve that is connected directly to the brain
- down-regulation
- a compensatory reduction in receptor availability at the synapses of a neuron
- up-regulation
- a compensatory increase in receptor availability at the synapses of a neuron
- retrograde synapse
- a synapse in which a signal (usually a gas neurotransmitter) flows from the postsynaptic neuron to the presynaptic neuron, thus counter to the usual direction of synaptic connection
- horizontal plane
- the plane that divides the brain into upper and lower parts
- autonomic nervous system
- the part of the peripheral nervous system that supplies neural connections to glands and to smooth muscles of internal organs
- presynaptic membrane
- the specialized membrane of the axon terminal of the neuron that transmits information by releasing neurotransmitter
- dissociative drug
- a type of drug that produces a dreamlike state in which consciousness is partly separated from sensory inputs
- arachnoid
- the thin covering (one of the three meninges) of the brain that lies between the dura mater and pia mater
- ribosomes
- structures in the cell body where genetic information is translated (proteins are produced)
- functional MRI (fMRI)
- magnetic resonance imaging that detects changes in blood flow and therefore identifies regions of the brain that are particularly active during a given task
- withdrawal symptom
- an uncomfortable symptom that arises when a person stops taking a drug that her or she has used frequently, especially at high doses
- LSD
- also called acid; lysergic acid diethylamide, a hallucinogenic drug
- sulcus
- a furrow of a convoluted brain surface
- efficacy/intrinsic activity
- the extent to which a drug activates a response when it binds to a receptor
- ectopic transmission
- cell-cell communication based on release of neurotransmitter in regions outside traditional synapses