A

Abducens nerve

Cranial nerve VI - innervates the lateral rectus muscle of the eye. It is the only cranial nerve that originates from the dorsal surface of the brainstem.

Ablation

Removal or destruction of tissue.

 

Acetylcholine (ACh)

A neurotransmitter found in the brain, spinal cord, neuromuscular junction and autonomic nervous system.

Acetylcholinesterase (AChE)

Enzyme that terminates the action of acetylcholine.

Action Potential

Electrical "all-or-none" impulse that transmits information within the nervous system.

Adrenergic

Associated with catecholamines.

Afferent

Neural information flowing from the periphery to more central areas of the nervous system.

Aging and the brain

Agonist

Chemical that acts like a neurotransmitter; increases the effect of a neurotransmitter.

Alzheimer's disease

A degenerative brain disease. Characterized by memory loss and disorientation.

Amnesia

Partial or complete loss of memory. "Anterograde" amnesia is when people cannot form new memories.

Amphetamine

A synthetic central nervous system stimulant.

Amplitude

The size or magnitude of a signal or response.

Amygdala

Brain structure that is part of the limbic system. Implicated in emotion.

 

Analgesia

Insensitivity to pain.

 

Antagonist

Chemical that blocks the action of a neurotransmitter

Anterior

A directional term meaning toward the front.

Anterior Commissure

A small fiber tract that connects the right and left cerebral hemispheres (like the corpus callosum).

Aphasia

Inability to speak or understand language.

Aqueous humor

Fluid in the space between the cornea and lens of the eye.

Arachnoid

Middle layer of the meninges.

Astrocyte (astroglia)

A glial cell that supports neurons.

Attention Deficit Hyperactivity Disorder

Autonomic Nervous System

Autoradiography

Neuroanatomical method using radioactivity that is incorporated into neurons.

Axon

The part of the neuron that takes information AWAY from the cell body.

Axodendritic (synapse)

A synapse formed by contact between a presynaptic axon and a postsynaptic dendrite.

B

Basal Ganglia

Areas of the brain that are important from movement. These areas include the putamen, caudate nucleus, globus pallidus, subthalamic nucleus and substantia nigra.

Bipolar neuron

Neuron with only two processes extending from the cell body.

Blood Brain Barrier

A system of astrocytes and capillaries in the brain that prevents the passage of specific substances.

Brainstem

The central core of the brain.

C

Cauda equina

The "horse's tail" made up of a bundle of spinal nerves at the base of the spinal cord.

Caudal

A directional term meaning toward the tail end.

Cell Body

Also called the soma; the part of the cell that contains the nucleus.

Central Nervous System

The brain and spinal cord.

Central Sulcus

Large groove in the brain that separates the frontal and parietal lobes.

Cerebellum

Area of the brain above the pons and medulla that is important for balance and posture.

Cerebral Aqueduct

Part of the ventricular system that connects the third and fourth ventricles.

Cerebral Cortex

Outermost layer (the gray matter) of the cerebral hemisphere.

 

Cerebrospinal Fluid (CSF)

Clear fluid in the ventricular system.

 

Chimeric Figure

Figure using two separate faces on each half. These figures are used in split brain experiments.

Choroid Plexus

Vascular structures in the ventricular system that produce cerebrospinal fluid.

Cingulate Cortex

Part of the limbic system. Located directly above the corpus callosum. Important for emotional behavior.

Circadian

About one day; used to describe some body rhythms.

Cochlea

Inner ear structure important for hearing.

Cone

Receptor found in the retina important for color vision and detailed sight.

Cornea

Transparent front coat of the eye.

Corpus Callosum

Large collection of axons that connect the left and right hemispheres of the brain.

Cranial Nerves

12 pairs of nerves that exit from the brain.

Cranium

The part of the skull that contains the brain.

D

Dendrite

Extensions from the neuron cell body that take information TO the cell body.

Depolarization

Movement of the membrane potential toward 0 mV; a decrease in polarization.

Dopamine

A neurotransmitter found in many areas of the brain. Important for movement and other behavior.

Dorsal Root

Bundle of nerve fibers taking information into the spinal cord.

Drug Effects on the Brain

Dura

Outermost layer of the meninges.

E

Electroencephalogram (EEG)

Record of electrical activity of the brain obtained from scalp electrodes.

Endorphin

Neurotransmitter with similar properties as opiates. Important for pain reduction.

Excitatory Postsynaptic Potential (EPSP)

A graded depolarization of the postsynaptic cell.

F

Fetal Alcohol Syndrome

Fornix

Pathway that connects the hippocampus with the mamillary bodies.

Fovea

Central part of retina; area of retina with most accurate vision.

G

Glia

Non-neural support cells of the nervous system.

Gyrus (plural is gyri)

"Hills" or "bumps" on the brain that are separated by fissures.

H

Hippocampus

Area of the limbic system important for memory.

Hormones

Chemicals used by endocrine system to transmit messages.

Hypothalamus

Brain structure that monitors internal environment and attempts to maintain balance of these systems. Controls the pituitary.

I

Inferior Colliculus

Midbrain structure important for hearing.

Iris

Muscles of eye that control the size of the pupil. Gives color to the eye.

J

K

L

Lens

Transparent structure in the eye that focuses light on the retina.

Lesion

Injury caused by destruction of tissue.

Limbic System (or Limbic Areas)

Interconnected areas of the brain important for emotional and other behaviors.

M

Medulla

Part of the brain stem important for breathing, respiration and other behaviors.

Meninges

Series of 3 membranes (dura mater, arachnoid, pia mater) that cover the brain and spinal cord.

Myelin Sheath

Fatty substance that surrounds some axons.

N

Neurotransmitters

Chemicals that transmit information across the synapse to communicate from one neuron to another.

Node of Ranvier

Short unmyelinated segment of an axon.

O

Occipital Lobe

Area of the brain located behind the parietal lobe and temporal lobe and responsible for vision.

Optic Chiasm

Crossing of the fibers from each retina.

Ossicles

Bones in the middle ear.

P

Parkinson's disease

Neurological disorder caused by damage to the dopamine system of the brain; symptoms include tremor, rigidity, slow movement.

Pia

Inner most layer of the meninges. Adjacent to the surface of the brain.

Pituitary

"Master" gland attached to the base of the brain that secretes hormones.

Pons

Area of the brainstem between the medulla and the midbrain.

Proprioceptor

Sensory receptor providing information related to body position, mainly in muscles and tendons

Q

R

Retina

Innermost layer of the eye; contains receptors responsive to light.

Rod

Receptor found in the retina important for in low light conditions.

S

Soma

The neuron cell body. Contains the nucleus.

Sulcus (plural is sulci)

Groove located on the surface of the brain.

Synapse

Functional connection between a terminal of one neuron with a membrane of another neuron.

T

Tectum

"Roof" of the midbrain.

Tegmentum

"Floor" of the midbrain.

Thalamus

Group of nuclei in the diencephalon of the brain. The different nuclei have sensory and motor functions.

V

Ventricles

Hollow spaces within the brain that are filled with cerebrospinal fluid.

W
X
Y
Z

1. Glossary - Brain Injury Terms
2. Glossary - Jane's Brain Page
3. Glossary - Brain Tumor Terms
4. Glossary - Neurobiology
5. Glossary - Society for Neuroscience
6. Glossary - Vestibular Terms
7. Glossary - "Visionary": terminology in vision research
8. Glossary - Neuro Vocabulary Guide
9. Glossary - W. Calvin's The Cerebral Code Vocabulary