Neurologic Terms

Axon

A long, slender part of a neuron that carries electrical signals away from the cell body to other neurons, muscles, or glands

Myelin

A fatty insulating layer surrounding many axons that increases the speed and efficiency of nerve signal transmission

Neurotransmitter

A chemical messenger released by a neuron that transmits signals to another neuron or to a muscle or gland

Encephalitis

Inflammation of the brain, often caused by infection, immune-mediated disease, or other inflammatory processes

Myelitis

Inflammation of the spinal cord that can cause neurologic dysfunction, including weakness, paralysis, or abnormal sensation

Meningitis

Inflammation of the meninges, the protective membranes surrounding the brain and spinal cord

Meningoencephalitis

Inflammation of both the meninges and the brain

Seizure

A sudden, abnormal, excessive, and synchronized electrical activity of neurons in that brain that can cause changes in movement, behavior, sensation, or consciousness

Epilepsy

A neurological disorder characterized by recurrent, unprovoked seizures caused by abnormal electrical activity in the brain

Focal seizure

A seizure that begins in a specific, localized region of the brain and may cause signs related to the area affected

Generalized seizure

A seizure involving widespread electrical activity in both sides of the brain, often resulting in loss of consciousness and bilateral motor activity

Ictal

The period during which a seizure is actively occurring

Postictal

The period immediately following a seizure, during which an animal may show temporary confusion, altered behavior, weakness, or abnormal neurologic function

Seizure threshold

The level of neuronal activity required to trigger a seizure; factors that lower the threshold make seizures more likely to occur

Status epilepticus

A prolonged seizure or a series of seizures occurring without adequate recovery of consciousness between seizures; it is a medical emergency

Cerebrospinal fluid

A clear fluid that surrounds and protects the brain and spinal cord and can be analyzed to help identify inflammation, infection, or other diseases of the central nervous system