Key terms Exam 1 Flashcards
declarative memory
Memories available to consciousness that can be expressed by language.
long-term memory
Memories that last days, weeks, months, years, or a lifetime.
nondeclarative memory
Unconscious memories such as motor skills and associations. Also called procedural memory.
action potential
The electrical signal conducted along axons (or muscle fibers) by which information is conveyed from one place to another in the nervous system.
afferent
A neuron or axon that conducts action potentials from the periphery toward the central nervous system.
anterograde
Signals or impulses that travel “forward,” e.g., from the cell body to the axon terminal, from the presynaptic terminal to the postsynaptic cell, or from the CNS to the periphery.
associational systems
Neural cell circuits that are not part of the relatively defined sensory (input) and motor (output) systems; they mediate the most complex and least well defined brain functions.
astrocytes
One of the three major classes of glial cells found in the central nervous system; important in regulating the ionic milieu of nerve cells and, in some cases, transmitter reuptake.
Axon
The neuronal process that carries the action potential from the nerve cell body to a target.
axon hillock
Point at the cell body that is the site of an action potential’s initiation.
central nervous system (CNS)
The brain and spinal cord of vertebrates (by analogy, the central nerve cord and ganglia of invertebrates).
chemical synapses
Synapses that transmit information via the secretion of chemical signals (neurotransmitters).
cognitive neuroscience
The field of neuroscience devoted to studying and understanding cognitive functions.
commissures
Axon tracts that cross the midline of the brain.
computational mapping
Central process of assessing and integrating multiple stimulus attributes into an orderly representation that facilitates the extraction and processing of essential information (e.g., the number and configuration of odorant molecules in order to determine the source and nature of a smell).
convergence
Innervation of a target cell by axons from more than one neuron. In vision refers specifically to the convergence of both rod and cone photoreceptor cells onto retinal ganglion cells.
cortex
The superficial mantle of gray matter (a sheet-like array of nerve cells) covering the cerebral hemispheres and cerebellum, where most of the neurons in the brain are located.
cranial nerve ganglia
The sensory ganglia associated with the cranial nerves; these correspond to the dorsal root ganglia of the segmental nerves of the spinal cord.
dendrite
A neuronal process arising from the nerve cell body that receives synaptic input.
divergence
The branching of a single axon to innervate multiple target cells.
dorsal root ganglia (DRG)
The segmental sensory ganglia of the spinal cord; they contain the first-order neurons of the dorsal column/medial lemniscus and spinothalamic pathways.
efferent
A neuron or axon that conducts information away from the central nervous system toward the periphery.
efferent
A neuron or axon that conducts information away from the central nervous system toward the periphery.
electrical synapses
Synapses that transmit information via the direct flow of electrical current at gap junctions.
electrophysiological recording
Measure of the electrical activity across the membrane of a nerve cell by use of electrodes. Extracellular recording places the electrode outside but nearby the cell of interest; intracellular recording places the electrode is placed inside the cell of interest.
enteric system
A subsystem of the visceral motor system, made up of small ganglia and individual neurons scattered throughout the wall of the gut; influences gastric motility and secretion.
ganglion (ganglia)
Collection of hundreds to thousands of neurons found outside the brain and spinal cord along the course of peripheral nerves.
gap junction
A specialized intercellular contact formed by channels that directly connect the cytoplasm of two cells.
gene
Hereditary unit located on the chromosomes; genetic information is carried by linear sequences of nucleotides in DNA that code for corresponding sequences of amino acids.
genomics
Scientific field focusing on the analysis of DNA sequences, including both protein-coding DNA (genes) and non-coding DNA.
glial cells (glia)
The support cells associated with neurons (astrocytes, oligodendrocytes, and microglial cells in the central nervous system; Schwann cells in peripheral nerves; and satellite cells in ganglia).
glial stem cells
Neural precursor cells in the adult brain that retain the capacity to proliferate and generate both additional precursor cells and differentiated glial cells (and, in some cases, differentiated neurons).
gray matter
General term that describes regions of the central nervous system rich in neuronal cell bodies and neuropil; includes the cerebral and cerebellar cortices, the nuclei of the brain, and the central portion of the spinal cord.