a rapid change from a negative to a positive electrical potential in a nerve cell. This signal travels along an axon without a change in intensity.
part of the forebrain of vertebrates that is involved in the production of appropriate behavioral responses to environmental stimuli.
Autonomic Nervous System
the part of the peripheral nervous system of vertebrates that synapses on glands, internal organs, and smooth muscle and produces largely involuntary responses.
a long extension of a nerve cell, extending from the cell body to synaptic endings on other nerve cells or on muscles. .
Several clusters of neurons in the interior of the cerebrum, plus the substantial nigra in the midbrain, that function in the control of movement. Damage to or degeneration of one or more basal ganglia causes disorders such as Parkinsons disease and Huntington's disease.
relatively impermeable capillaries of the brain that protect the cells of the brain from potentially damaging chemicals that reach the bloodstream.
the part of the central nervous system of vertebrates that is enclosed within the skull.
the part of a nerve cell in which most of the common cellular organelles are located; typically a site of integration of inputs to the nerve cell.
Central Nervous System (CNS)
in vertebrates, the brain and spinal cord.
the part of the hindbrain of vertebrates that is concerned with coordinating movements of the body.
a thin layer of neurons on the surface of the vertebrate cerebrum, in which most neural processing and coordination of activity occurs.
one of two nearly symmetrical halves of the cerebrum, connected by a broad band of axons, the corpus callosum.
the part of the forebrain of vertebrates that is concerned with sensory processing, the direction of motor output, and the coordination of most bodily activities; consists of two nearly symmetrical halves (the hemispheres) connected by a broad band of axons, the corpus callosum.
a folding of the cerebral cortex of the vertebrate brain.
the band of axons that connect the two cerebral hemispheres of vertebrates.
a branched tendril that extends outward from the cell body of a neuron; specialized to respond to signals from the external environment or from other neurons.
Dorsal Root Ganglion
a ganglion, located on the dorsal (sensory) branch of each spinal nerve, that contains the cell bodies of sensory neurons.
a part of the body (normally a muscle or gland) that carries out responses as directed by the nervous system.
Excitatory postsynaptic potential (EPSP)
an electrical signal produced in a postsynaptic cell that makes the resting potential of postsynaptic neuron less negative and hence, makes the neuron more likely to produce an action potential.
during development, the anterior portion of the brain. In mammals, the forebrain differentiates into the thalamus, the limbic system, and the cerebrum. In humans, the cerebrum contains about half of all the neurons in the brain.
Ganglion (Plural; Ganglia)
a cluster of neurons.
cells of the nervous system that provide nutrients for neurons, regulate the composition of extracellular fluid in the brain and spinal cord, modulate communication between neurons, and insulate axons, thereby speeding up the conduction of action potentials. (also known as glial cells)
the outer portion of the brain and inner region of the spinal cord; composed largely of neuron cell bodies, which give this area a gray color.
the posterior portion of the brain, containing the medulla, pons, and cerebellum.
the part of the forebrain of vertebrates that is important in emotion and especially learning.
a region of the brain that controls the secretory activity of the pituitary gland; synthesizes, stores, and releases certain peptide hormones; directs autonomic nervous system responses.
Inhibitory Postsynaptic Potential (IPSP)
an electrical produced in a postsynaptic cell that makes the resting potential more negative and, hence, makes the neuron less likely to fire an action potential.
in nerve cells, the process of adding up electrical signals from sensory inputs or other nerve cells to determine the appropriate outputs.
the strength of stimulation or response.
a neutral network, a nerve cell that is postsynaptic to a sensory neuron and presynaptic to a motor neuron. In actual circuits, these may be between individual sensory and motor neurons.
a diverse group of brain structures, mostly in the lower forebrain, that includes the thalamus, hypothalamus, amygdala, hippocampus, and parts of the cerebrum and is involved in basic emotions, drives, behaviors, and learning.
the second phase of learning; a more-or-less permanent memory formed by a structural change in the brain, brought on by repetition.
the part of the hindbrain of vertebrates that controls automatic activities such as breathing, swallowing, heart rate, and blood pressure.
during development, the central portion of the brain; contains an important relay center, the reticular formation.
a neuron that receives instructions from the association neurons and activates effector organs, such as muscles or glands.
a wrapping of insulating membranes of specialized nonneural cells around the axon of a vertebrate nerve cell; increases the speed of conduction of action potentials.
a bundle of axons of nerve cells, bound together in a sheath.
a simple form of nervous system, consisting of a network of neurons that extend throughout the tissues of an organism such as a cnidarian.
a single nerve cell.
a chemical that is released by a nerve cell close to a second nerve cell, a muscle, or a gland cell and that influences the activity of the second cell.
the division of the autonomic nervous system that produces largely involuntary responses related to the maintenance of normal body functions, such as digestion.
Peripheral Nervous System (PNS)
in vertebrates, the part of the nervous system that connects the central nervous system to the rest of the body.
a portion of the hindbrain, just above the medulla, that contains neurons that influence sleep and the rate and pattern of breathing.
at a synapse, the nerve cell that changes its electrical potential in response to a chemical (the neurotransmitter) released by another (presynaptic) cell.
Postsynaptic Potential (PSP)
an electrical signal produced in a postsynaptic cell by transmission across the synapse; it may be excitatory (EPSP), making the cell more likely to produce an action potential, or inhibitory (IPSP), tending to inhibit an action potential.
a nerve cell that releases a chemical (the neurotransmitter) at a synapse, causing changes in the electrical activity of another (postsynaptic) cell.
a simple, stereotyped movement of part of the body that occurs automatically in response to a stimulus.
a negative electrical potential in unstimulated nerve cells.
a diffuse network of neurons extending from the hindbrain, through the midbrain, and into the lower reaches of the forebrain; involved in filtering sensory input and regulating what information is relayed to conscious brain centers for further attention.
a nerve cell that responds to a stimulus from the internal or external environment.
Sodium-Potassium (Na+-K+) Pump
in nerve cell plasma membranes, a set of active-transport molecules that use the energy of ATP to pump sodium ions out of the cell and potassium ions in, maintaining the concentration gradients of these ions across the membrane.
Somatic Nervous System
that portion of the peripheral nervous system that controls voluntary movement by activating skeletal muscles.
the part of the central nervous system of vertebrates that extends from the base of the brain to the hips and is protected by the bones of the vertebral column; contains the cell bodies of motor neurons that form synapses with skeletal muscles, the circuitry for some simple reflex behaviors, and axons that communicate with the brain.
the division of the autonomic nervous system that produces largely involuntary responses that prepare the body for stressful or highly energetic situations.
the site of communication between nerve cells. At a synapse, one cell (presynaptic) normally releases a chemical (the neurotransmitter) that changes the electrical potential of the second (postsynaptic) cell.
in a synapse, a small gap between the presynaptic and postsynaptic neurons.
a swelling at the branched ending of an axon; where the axon forms a synapse.
the part of the forebrain that relays sensory information to many parts of the brain.
the electrical potential (less negative than the resting potential) at which an action potential is triggered.
the portion of the brain and spinal cord that consists largely of myelin-covered axons and that give these areas a white appearance.
the first phase of learning; short-term memory that is electrical or biochemical in nature.