Term
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Definition
| A large bundle of nerve fibers that connect corresponding parts of one side of the brain with those of the other |
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Term
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Definition
| Brain surgery that is occasionally performed to treat a form of epilepsy; the surgeion cuts the corpus callosum, which connects the two hemispheres of the brain. |
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Term
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Definition
| Type of scientific explanation; a general conclusion based on many observations of similar phenomena. |
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Term
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Definition
| Type of scientifica explanation; a phenomenon is described in terms of the more elementary processes that underlie it. |
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Term
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Definition
| An autonomic, stereotyped movement produced as the direct result of a stimulus. |
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Term
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Definition
| A mathematical or physical analogy for physiological process; for example, computers have been used as models for various functions of the brain. |
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Term
| doctrine of specific nerve energies |
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Definition
| Muller's conclusion that because all nerve fibers carry the same type of message, sensory information must be specified by the particular nerve fibers that are active. |
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Term
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Definition
| The research method in which the function of a part of the brain is inferrred by observing the behaviors, and animal can no longer perform after that part is damaged. |
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Term
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Definition
| The principle that the best way to understand a biological phenomenon (a behavior or a physiological structure) is to try to understand its useful functions for the organism. |
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Term
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Definition
| The process by which inherited traits that confer a selective advantage (increase an animal's likelihood to live and reproduce) become more prevalent in the population. |
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Term
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Definition
| A change in the genetic information conatained in the chromosomes of sperms or eggs, which can be passed on to an organism's offspring; provides genetic variability. |
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Term
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Definition
| A characteristics of an organism that permits it to produce more than the average number of offspring of its species. |
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Term
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Definition
| A gradual change in the structure and physiology of plant and animal species--generally producing more organisms--as a result of natural selection. |
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Term
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Definition
| A slowing of the process of maturation, allowing more time for growth; and important factor in the development of large brains. |
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Term
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Definition
| A neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system. |
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Term
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Definition
| A neuron located within the central nervous system that controls the contraction of a muscle or the secretion of a gland. |
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Term
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Definition
| A neuron located entirely within the central nervous system. |
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Term
| central nervous systen (CNS) |
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Definition
| The brain and spinal cord |
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Term
| peripheral nervous system (PNS) |
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Definition
| The part of the nervous system outside the brain and spinal cord, including the nerves attached to the brain and spinal cord. |
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Term
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Definition
| The cell body of a neuron, which contains the nucleus. |
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Term
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Definition
| A branched, treelike structure attached to the soma of a neuron; receives information from the terminal buttons of other neurons. |
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Term
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Definition
| A junction between the terminal button of an axon and the membrane of another neuron. |
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Term
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Definition
| The long, thin, cylindrical structure that conveys information from the soma of neuron to its terminal buttons. |
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Term
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Definition
| A neuron with one axon and many dendrites attached to its soma. |
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Term
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Definition
| A neuron with one axon and one dendrite attached to its soma.(primarily found in sensory systems such as vision and audition |
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Term
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Definition
| A neuron with one axon attached to its soma; the axon divides, one branch receiving sensory information and the other sending the information into the cental nervous system. (found in the somatosensory system, like touch, pain, etc.) |
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Term
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Definition
| The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron. |
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Term
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Definition
| A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron. |
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Term
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Definition
| A structrue consisting principally of lipid molecules that defines the outer boundaries of a cell and also constitutes many of the cell organelles. |
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Term
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Definition
| The viscous, semiliquid substance contained in the interior of a cell. |
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Term
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Definition
| An organelle that is responsible for extracting energy from nutrients. |
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Term
| adenosine triphosphate (ATP) (ah deno seen) |
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Definition
| A molecule of prime importance to cellular energy metabolism; its breakdown liberates energy. |
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Term
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Definition
| A structure in the central region of a cell, containing the chromosomes. |
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Term
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Definition
| A strand of DNA, with associated proteins, found in the nucleus; carries genetic information. |
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Term
deoxyribonucleic acid (DNA)
(dee ox ee ry bo new clay ik) |
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Definition
| A long, complex macromolecule consisting of two interconnected helical strands; along with associated proteins, strands of DNA constitute the chromosomes. |
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Term
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Definition
| The functional unit of the chromosome, which directs synthesis of one or more proteins. |
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Term
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Definition
| Formed of microtubules and other protein fibers, linked to each other and forming a cohesive mass that gives a cell its shape. |
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Term
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Definition
| A molecule that controls a chemical reaction, combining two substances or breaking a substance into two parts. |
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Term
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Definition
| An active process by which substances are propelled along microtubles that run the length of the axons |
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Term
| microtubule (my kro too byool) |
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Definition
| A long stand of bundles of protein filaments arranged around a hollow core; part of the cytoskeleton and involved in transporting substances from place to place within the cell. |
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Term
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Definition
| The supporting cells of the central nervous system. |
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Term
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Definition
| A glial cell that provides support for neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid. |
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Term
| phagocytosis (fagg o sy toe sis) |
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Definition
| The process by which cells engulf and digest other cells or debris caused by cellular degeneration. |
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Term
| oligodendrocyte (oh li go den droh site) |
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Definition
| A type of glial cell in the central nervous system that forms myelin sheaths. |
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Term
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Definition
| A sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons. |
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Term
| node of Ranvier (raw vee ay) |
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Definition
| A naked protion of a myelinated axon, between adjacent oligodendroglia or Schwann cells. |
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Term
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Definition
| The smallest of glial cells; act as phagocytes and protect the brain from invading microorganisms. |
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Term
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Definition
| A cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath. |
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Term
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Definition
| A semipermeable barrier between the blood and the brain produced by the cells in the walls of the brain's capillaries. |
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Term
| area postrema (poss tree ma) |
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Definition
| A region of the medulla where the blood-brain barrier is weak; poisons can be detected there and can initiate vomiting. |
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Term
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Definition
| A conductive medium that can be used to apply electrical stimulation or to record electrical potentials. |
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Term
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Definition
| A very fine electrode, generally used to record activity of individual neurons. |
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Term
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Definition
| The electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell. |
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Term
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Definition
| A laboratory instrument that is capable of displaying a graph of voltage as a function of time on the face of a cathode ray tube. (CRT) |
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Term
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Definition
| The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials; approximately -70 mV in the giant squid axon. |
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Term
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Definition
| Reduction (toward zero) of the membrane potential of a cell from its normal resting potential. |
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Term
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Definition
| An increase in the membrane potential of a cell, relative to the normal resting potential. |
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Term
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Definition
| The breif electrical impulse that provides the basis for conduction of information along an axon. |
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Term
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Definition
| The value of the membrane potential that must be reached to produce an action potential. |
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Term
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Definition
| Movement of mulecules from regions of high concentration to regions of high concentration to regions of low concentration. |
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Term
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Definition
| An aqueous solution of a material that ionizes--namely, a soluble acid, base, or salt. |
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Term
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Definition
| A charged molecule Cations are postively charged, and anions are negatively charged. |
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Term
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Definition
| The attractive force between atomic particles charged with opposite signs or the repulsive force between atomic particles charged with the same sign. |
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Term
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Definition
| The fluid contained within cells. |
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Term
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Definition
| Body fluids located outside of cells. |
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Term
| sodium-potassium transporter |
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Definition
| A protei found in the membrane of all cells that extrudes sodium ions from and transports potassium ions into the cell. |
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Term
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Definition
| A specialized protein molecule that permits specific ions to enter or leave cells. |
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Term
| voltage-dependent ion channel |
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Definition
| An ion channel that opens or closes according to the value of the membrane potential. |
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Term
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Definition
| The principle that once an action potential is triggered in an axon, it is propagated, without decrement, to the end of the fiber. |
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Term
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Definition
| The principle that variations in the intensity of a stimulus or other information being transmitted in an axon are represented by variations in the rate at which the axons fire. |
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Term
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Definition
| Conduction of actions potentials by myelinated axons. The action potential appears to jump from one node of Ranvier to the next. |
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Term
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Definition
| Alterations in the membrane potential of a postsynaptic neuron, produced by liberation of neurotransmitter at the synapse. |
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Term
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Definition
| The location on a receptor protein to which a ligand binds. |
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Term
| ligand (ligh gand or ligg and) |
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Definition
| A chemical that binds with the binding site of a receptor. |
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Term
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Definition
| A small b ud on the surface of a dendrite, with which a terminal button of another neuron forms a synapse. |
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Term
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Definition
| The membrane of a teminal button that lies adjacent to the postsynaptic membrane and through which the neurotransmitter is released. |
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Term
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Definition
| The cell membrane opposite the terminal button in a synapse; the membrane of the cell that recieves the message. |
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Term
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Definition
| The space between the presynaptic membrane and the postsynaptic membrane. |
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Term
| synaptic vesicle (vess i kul) |
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Definition
| A small, hollow, beadlike structure found in terminal buttons; contains molecules of a neurotransmitter. |
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Term
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Definition
| A region of the interior of the presynaptic membrane of a synapse to which synaptic vesicles attach and release their neurotransmitter into the synaptic cleft. |
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Term
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Definition
| A receptor molecule in the postsynaptic membrane of a synapse that contains a binding site for a neurotransmitter. |
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Term
| neurotransmitter-dependent ion channel |
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Definition
| An ion channel that opens when a molecule of a neurotransmitter binds with a postsynaptic receptor. |
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Term
| ionotropic receptor (eye on oh trow pik) |
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Definition
| A receptor that contains a binding site for a neurotransmitter and an ion channel that opens with a molecule of the neurotransmitter. |
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Term
| metabotropic receptor (meh tab oh trow pik) |
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Definition
| A receptor that contains a binding site for a neurotransmitter; acitvates an enzyme that begins a series of events that opens an ion channel elsewhere in the membraine of the cell when a molecule of the neurotransmitter attaches to the binding site. |
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Term
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Definition
| A protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activates the receptor. |
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Term
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Definition
| A chemical produced when a G protein activates an enzyme; carries a signal that results in the opening of the ion channel or causes other evnets to occur in the cell. |
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Term
| excitatory postsynatic potential (EPSP) |
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Definition
| An excitatory depolarization of the postsynaptic membrane of the synapse caused by the liberation of a neurotansmitter by the terminal button. |
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Term
| inhibitory postsynaptic potential (IPSP) |
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Definition
| An inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button. |
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Term
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Definition
| The reentry of a neurotransmitter just liberated by a terminal button back through its membrane, thus terminating the postsynaptic potential. |
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Term
|
Definition
| The destruction of a neurotransmitter by an enzyme after its release--for example, the destruction of acetylcholine by acetylcholinesterase. |
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Term
| acetylcholin (ACh) (a see tul koh leen) |
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Definition
| A neurotransmitter found in the brain, spinal cord, and parts of the peripheral nervous system; responsible for muscular contraction. |
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Term
acetylcholinesterase (AChE)
(a see tul koh lin ess ter ace) |
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Definition
| The enzyme that destroys acetylcholine soon after it is liberated by the terminal buttons, thus terminating the post-synaptic potential. |
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Term
|
Definition
| Ther process by which inhibitory and excitatory postsynaptic potentials summate and control the rate of firing of a neuron. |
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Term
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Definition
| A receptor molecule located on a neuron that responds to the neurotransmitter released by that neuron. |
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Term
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Definition
| The action of a presynaptic terminal button in the axoaxonic synapse; reduces the amount of neurotransmitter released by the postsynaptic terminal button. |
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Term
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Definition
| The action of a presynaptic terminal button in an axoaxonic synapse; increases the amount of neurotransmitter released by the postsynaptic terminal button. |
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Term
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Definition
| A naturally secreted substance that acts like a neurotransmitter except that is is not restricted to the synaptic cleft but diffused through the extracellular fluid. |
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Term
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Definition
| A chain of amino acids joined together by peptide bonds. Most neuromodulators and some hormones consist of peptide molecules. |
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Term
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Definition
| A chemical substance that is released b an endocrine gland and that has effects on target cels in other organs. |
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Term
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Definition
| A gland that liberates its secretions into the extracellular fluid around capillaries and hence into the bloodstream. |
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Term
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Definition
| The type of cell that contains receptors for a particular hormone and is affected by that hormone. |
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Term
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Definition
| An imaginary line drawn through the center of the length of the central nervous system, from the bottom of the spinal cord to the front of the forebrain. |
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Term
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Definition
| With respect to the central nervous system, located near or toward the head. |
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Term
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Definition
| With respect to the central nervous system, located near or toward the tail. |
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Term
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Definition
| "Toward the beak"; with respect to the central nervous system, in a direction alond the neuraxis toward the front of the face. |
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Term
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Definition
| "Toward the tail"; with respect to the central nervous system, in a direction along the neuraxis away from the front of the face. |
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Term
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Definition
| "Toward the back"; with respect to the central nervous system, in a direction perpendicular to the neuraxis toward the top of the head or the back. |
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Term
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Definition
| "Toward the belly"; with respect to the central nervous system, in a direction perpendicular to the neuraxis toward the bottom of the skull or the front surface of the body. |
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Term
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Definition
| Toward the side of the body away from the middle. |
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Term
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Definition
| Toward the middle of the body away from the side |
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Term
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Definition
| Located on the same side of the body |
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Term
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Definition
| Located on the opposite side of the body. |
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Term
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Definition
| With respect to the central nervous system, a slice taken at right angles to the neuraxis. |
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Term
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Definition
| A slice through the brain parallel to the forehead. |
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Term
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Definition
| A slice through the brain parallel to the ground. |
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Term
| sagittal section (sadj i tul) |
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Definition
| A slice through the brain parallel to the neuraxis and perpendicular to the ground. |
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Term
|
Definition
| The plane through the neuraxis perpendicular to the ground; divides the brain into two symmetrical halves. |
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Term
| meninges (singular meninx) (men in jees) |
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Definition
| The three layers of tissue that encase the central nervous system; the dura mater, arachnoid membrane, and pia mater. |
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Term
|
Definition
| The outermost of the meninges; tough and flexible. |
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Term
| Arachnoid membrane (a rak noyd) |
|
Definition
| The middle layer of the meninges, located between the outer dura mater and inner pia mater. |
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Term
|
Definition
| The layer of the meninges that clings to the surfce of the brain; thin and delicate. |
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Term
|
Definition
| The fluid-filled space that cushions the brain; located between the arachnoid membrane and the pia mater. |
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Term
| cerebrospinal fluid (CSF) |
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Definition
| A clear fluid, similar to blood plasma, that fills the ventricular system of the brain and the subarachnoid space surrounding the brain and spinal cord. |
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Term
|
Definition
| One of the hollow spaces within the brain, filled with cerobrospinal fluid. |
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Term
|
Definition
| One of the two ventricles located in the center of the telenphalon. |
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Term
|
Definition
| The ventricle located in the center of the diencephalon. |
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Term
|
Definition
| A norrow tube interconnecting the third and fourth ventricles of the brain, located in the center of the mesencephalon. |
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Term
|
Definition
| The ventricle located between the cerebellum and the dorsal pons, in the center of the metencephalon. |
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Term
|
Definition
| The highly vascular tissue that protrudes into the ventricles and produces cerebrospinal fluid. |
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Term
|
Definition
| A hollow tuve, closed at the rostral end, that forms from ectodermal tissue early in embryonic development; serves as the origin of the central nervous system. |
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Term
|
Definition
| The outermost layer of gray matter of the cerebral hemispheres. |
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Term
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Definition
| A layer of cells that line the inside of the neural tube; contains progenitor cells that divide and give rise to cells of the central nervous system. |
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Term
|
Definition
| Cells of the ventricular zone that divide and give rise to cells of the central nervous system. |
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Term
|
Definition
| Divisions of a progenitor cell that gives rise to two identical progenitor cells; increases the size of the ventricular zone and hence the brain that develops from it. |
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Term
|
Definition
| Division of a progenitor cell that gives rise to another progenitor cell and neuron, which migrates aways from the ventricular zone toward its final resting place in the brain. |
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Term
|
Definition
| Special glia with fibers that grow radially outward from the ventricular zone to the surface of the cortex; provide guidance for neurons migrating outward during brain development. |
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Term
| Cajal-Retzius (C-R) cells |
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Definition
| Specialized neurons that establish themselves during cortical development in a layer near the terminals of the radial glia, just inside the pia mater; secrete a chemical that controls the establishment of migrating neurons in the layers of the cortex. |
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Term
| apoptosis (ay pop toe is) |
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Definition
| Death of a cell caused by a chemical signal that activates a genetic mechanism inside the cell. |
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Term
|
Definition
| The most rostral of the three major divisions of the brain; includes the telencephalon and diencephalon. |
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Term
| cerebral hemisphere (sa ree brul) |
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Definition
| One of the two major portions of the forebrain, covered by the cerebral cortex. |
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Term
|
Definition
| The region located within the brain, beneath the cortical surface. |
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Term
| sulcus (plural: sulci) (sul kus, sul sigh) |
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Definition
| A groove in the surface of the cerebral hemisphere, smaller that a fissure. |
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Term
|
Definition
| a major groove in the surface of the brain, larger than a sulcus. |
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Term
| gyrus (plural: gyri)(jye russ, jye rye) |
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Definition
| A convolution of the cortex of the cerebral hemispheres, separated by sulci or fissures. |
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Term
|
Definition
| The region of the posterior occipital lobe whose primary input is from the visual system |
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Term
| calcarine fissure (kal ka rine) |
|
Definition
| A fissure located in the occipital lobe on the medial surface of the brain; most of the primary visual cortes is located along its upper and lower banks. |
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Term
|
Definition
| The region of the superior temporal lobe whose primary input is from the auditory system. |
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Term
|
Definition
| The fissure that separates the temporal lobe from the overlying frontal and parietal lobes. |
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Term
|
Definition
| Includes most of the two symmetrical cerebral hemisphers that make up the cerebrum. |
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Term
| primary somatosensory cortex |
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Definition
| The region of the anterior parietal lobe whose primary input is from the somatosensory system. |
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Term
|
Definition
| The sulcus that separates the frontal lobe from the parietal lobe. |
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Term
|
Definition
| The region of the posterior frontal lobe that contains neurons that control movements of skeletal muscles. |
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Term
|
Definition
| The anterior portion of the cerebral cortex, rostral to the parietal lobe and dorasal to the temporal lobe. |
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|
Term
| parietal lobe (pa rye i tal) |
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Definition
| The region of the cerebral cortex caudal to the frintal lobe and dorsal to the temporal lobe. |
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|
Term
| temporal lobe (tem por ul) |
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Definition
| The region of the cerebral cortex rostral to the occipital lobe and ventral to the parietal and frontal lobes. |
|
|
Term
| occipital lobe (ok sip i tal) |
|
Definition
| The region of the cerbral cortex caudal to the parietal and temporal lobes. |
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|
Term
| sensory association cortex |
|
Definition
| Those regions of the cerebral cortex that receive information from the regions of primary sensory cortex. |
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Term
|
Definition
| The region of the frontal lobe rostral to the primary motor cortex; also known as the premotor cortex. |
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Term
|
Definition
| The region of the frontal lobe rostral to the motor association cortex. |
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|
Term
| corpus callosum (ka loh sum) |
|
Definition
| A large bundle of axons that interconnects corresponding regions of the association cortex on each side of the brain. |
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Term
|
Definition
| The phylogenetically newest cortex, including the primary sendory cortex, primary motor cortex, and association cortex. |
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Term
|
Definition
| Phylogenetically old cortex, located at the medial edge of the ("limbus") of the cerebral hemispheres, part of the limbic system. |
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|
Term
| cingulate gyrus (sing yew lett) |
|
Definition
| A strip of limbic cortex lying along the lateral walls of the groove separating the cerebral hemispheres, just above the corpus callosum. |
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Term
|
Definition
| A group of brain regions including the anterior thalamic nuclei, amygdala, hippocampus, limbic cortex, and parts of th hypothalamus, as well as their interconnecting fiber bundles. |
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