brachium of the superior colliculus


brachium of the superior colliculus 

A bundle of nerve fibres that leaves the optic tract below the pulvinar of the thalamus to enter the pretectal nucleus near the superior colliculus. Some fibres also connect the superior colliculus to the lateral geniculate body. Damage to the brachium results in a reduced pupil reflex to light, but not to near objects. See pretectal nucleus; pupil light reflex.