Monday, July 4, 2011
Dorsal Longitudinal Fasciculus
Situated within the brain stem, the dorsal longitudinal fasciculus is a bundle of fibers which is composed of descending hypothalamic axons and ascending visceral sensory axons. The descending fibers of the dorsal longitudinal fasciculus arises from the hypothalamus; these fibers then descend through the brain stem periaqueductal gray matter along the base of the fourth ventricle and continue on into the spinal cord where they synapse with preganglionic autonomic neurons. The ascending fibers of the dorsal longitudinal fasciculus originate in nuclei of the reticular formation; these fibers synapse onto the hypothalamus and carry visceral information to the brain.