4 terms

Commissural Fibers

The white matter underlying the cortex consists of myelinated axons running in three directions, association fibers (within the same hemisphere), commissural fibers (between hemispheres), and projection fibers. Projection fibers are ascending and descending tracts that transmit impulses from the cerebrum to other parts of the lower brain and spinal cord. Commissural fibers transmit impulses from one cerebral hemisphere to the opposite cerebral hemisphere. In slide 1, the three important groups of commissural fibers are shown; the corpus callosum (in yellow), the anterior commissure (in red), and the posterior commissure (in blue).
Select slide 2 to see the corpus callosum.
Select slide 3 to see the anterior commissure (identified by the arrow).
Select slide 4 to see the posterior commissure.