Cholinergic projections to the visual thalamus and superior colliculus.

The parabrachial region of the brainstem reticular formation projects to the dorsal lateral geniculate nucleus of the thalamus and to the intermediate gray layer of the superior colliculus. We used the retrograde axonal transport of two fluorescent labels to demonstrate that individual parabrachial cells project to both structures. The results suggest that cholinergic cells of the parabrachial region may coordinate the relay of visuosensory information to the cortex with the onset of orienting movements.