Decussation

Decussation: A crossing-over, as in the crossing of nerve fibers or tracts from one side of the brainstem to the other. Examples of decussation occur in the auditory and visual pathways in the brainstem and ventral surface of the brain, i.e., the comissural tract between the superior olivary nuclei and optic chiasm. In these two cases, decussation allows left- and right-side sensory information to reach both hemispheres of the brain equally. This is a safety mechanism; if damage occurs on one side of the sensory tract, the information from both eyes/ears may still reach the brain cortex (Synthesis of class notes, neuroanatomy).