What is the term for bundles of axons within the central nervous system's white matter?

• A. Tracts
• B. Nerves
• C. Ganglia
• D. Nuclei

Answer: (A)

Bundles of axons in the central nervous system’s white matter are called tracts. White matter consists of myelinated axons that form long-distance communication pathways within the CNS, connecting different brain regions and the spinal cord. A tract specifically denotes that these axons are bundled together as a pathway inside the CNS.

This differs from nerves, which are bundles of axons in the peripheral nervous system. Ganglia are clusters of neuronal cell bodies in the peripheral nervous system, while nuclei are clusters of neuronal cell bodies within the central nervous system. So the term that names the axon bundles in CNS white matter is tract.