In: Anatomy and Physiology
A. Commissural fibres:- commissural fibres or transverse fibres are the bundles of axons that connects the two hemispheres of the brain. Example- corpus callosum, anterior commissure, posterior commissure etc.
Projection fibres:- projection fibres are the bundles of axons consisting of afferent and efferent fibres that unites cortex to other parts of the brain or spinal cord. Example- corticopontine fibres that starts from cortex ending in the pontine nuclei etc.
Association fibres:- Association fibres are the bundles of axons that connects the different cortical areas within the same cerebral hemisphere. Example- superior longitudinal fasciculus that connects frontal lobes to occipital lobes etc.
B. White matter is the tissue through which messages pass between different areas of gray matter within the central nervous system.
White matter modulates the distribution of action potential.
It acts as a relay and coordinating communication between different brain regions.