Abnormal corpus callosum morphology Probst bundles 2021-11-24T12:09:26Z Probst bundles (also known as longitudinal callosal fascicles) are neuroanatomical homologues to the corpus callosum and can occur in association with callosal agenesis. Probst bundles are white matter fibers that normally cross the corpus callosum but (because of the agenesis of the corpus callosum) fail to cross the midline, such that when they reach the corticoseptal boundary, they turn and run parallel to the interhemispheric fissure within the septal leaves, indenting the medial walls of the lateral ventricles. The formation of Probst bundles is the most common structural anomaly associated with callosal dysgenesis.