Neuro glossary

Grey matter

one of the two main components of the brain. Composed of unmyelinated neurons as opposed to white matter (myelinated neurons). It has a grey brown color which comes from the capillary blood vessels and the neuronal cell bodies.

Nuclei (or nucleus)

A group of functionally related neurones.

Tract

A band of neuronal axons (+/-dendrites), which connect distant areas of the CNS. There are other names for the same thing:

• Fasciculus - probably completely interchangable.
• Peduncle - used only for tracts which are ridiculously massive that they make up a macroscopic part of the brain that you could pick with your fingers - assuming you're looking at a cadavar or have smashed someone's head in - and usually surounded by the CSF i.e. cerebral peduncles and the 3 cerebellar peduncles.

White matter

one of the two main components of the brain. Composed of myelinated axons which connect various grey matter areas (the locations of nerve cell bodies) of the brain to each other and carry nerve impulses between neurons.

Myotomes

Muscles supplied by a nerve.

Dermatomes

Skin supplied by a nerve.