Dorsal longitudinal fasciculus

The dorsal longitudinal fasciculus (DLF) is a distinctive nerve tract in the midbrain. It extends from the hypothalamus rostrally to the spinal cord caudally, and contains both descending and ascending fibers.

Descending fibers arise in the hypothalamus to project directly or indirectly onto autonomic nuclei and lower motor neurons of the brainstem and spinal cord; the descending component is involved in controlling chewing, swallowing, salivation and gastrointestinal secretory function, and shivering.

Among the ascending fibers is a serotonin pathway arising in the raphe nuclei.