1] In agenesis of corpus callosum, commissural fibers
do not cross the midline instead thick bundles of intersecting fibers called Probst bundles which lie along the super medial aspect of the lateral ventricles and the third ventricle may sometimes be displaced upward.
They describe the detailed wiring patterns of commissural fibers
connecting the right and left hemispheres of the cerebral cortex, in three dimensions, for the first time.
Aside from corpus callosum, these abnormalities may also reside in commissural fibers
such as anterior and posterior commissure, but less frequently.
By contrast, pontocerebellar projection fibers were particularly resistant to HIV effects, as were commissural fibers
coursing through premotor and sensorimotor callosal sectors (Pfefferbaum et al.
Quantitative analysis of myelinated axons of commissural fibers
in the rat brain.