Wednesday, June 29, 2011

Medial Longitudinal Fasciculus

The medial longitudinal fasciculus is either of a pair of bundles of fibers that stretches along the brainstem, from the upper border of the mesencephalon to the cervical segments of the spinal cord. The medial longitudinal fasciculus consists of fibers that arises from the vestibular nuclei running up to the motor neurons innervating the external eye muscles, and descending to spinal cord segments innervating the neck muscles. Descending fibers can also arise from the superior colliculus in the rostral midbrain for visual reflexes, the accessory occulomotor nuclei in the rostral midbrain for visual tracking, and the pontine reticular formation, which facilitates extensor muscle tone.