Visual areas of the brain must be connected to motor areas for the sensory
guidance of movement. The first step in the pathway from the primary visual
cortex is by way of the dorsal stream of visual areas in the parietal lobe
. The fact that monkeys can still guide their limbs visually after cortico-
cortical fibres have been severed suggests that there are subcortical route
s that link visual and motor areas of the brain. The pathway that runs from
the pens and cerebellum is the largest of these. Pontine cells that receiv
e inputs from visual cortical areas or the superior colliculus respond vigo
rously to appropriate visual stimuli and project widely on the cerebellar c
ortex. A challenge for future research is to elucidate the role of these ce
rebellar target areas in visuo-motor control.