Collections of Neurons

Question 1

A generic term for a collection of neuronal cell bodies in the CNS. When a freshly dissected brain is cut open, neurons appear gray.

Answer 1

Gray matter

Question 2

Any collection of neurons that form a thin sheet, usually at the brain’s surface. Cortex is Latin for “bark,” Example: cerebral cortex, the sheet of neurons found just under the surface of the cerebrum.

Answer 2

Cortex

Question 3

A clearly distinguishable mass of neurons, usually deep in the brain (not to be confused with nucleus of a cell). Nucleus is from the Latin word for “nut.” Example: lateral geniculate nucleus, a cell group in the brain stem that relays information from the eye to the cerebral cortex.

Answer 3

Nucleus

Question 4

A group of related neurons deep within the brain, but usually with less distinct borders than those of nuclei. Example: substantia nigra (from the Latin word for “black substance”), a brain stem cell group involved in the control of voluntary movement.

Answer 4

Substantia

Question 5

A small, well-defined group of cells. Example: locus coeruleus (Latin for blue spot), a brain stem cell group involved in the control of wakefulness and behavioral arousal.

Answer 5

Locus (plural: loci)

Question 6

A collection of neurons in the PNS. Ganglion is from the Greek for “knot.” Example: the dorsal root ganglia, which contain the cells bodies of sensory axons entering the spinal cord via the dorsal roots. Only one cell group in the CNS goes by this name: the basal ganglia, which are structures lying deep within the cerebrum that control movement.

Answer 6

Ganglion (plural: ganglia)