Saccadic and vergence functional activity in the pons

Processing visual signals from our external world and executing actions based upon that afferent information require contributions of not only cortical regions but also subcortical areas. The brainstem is an essential subcortical region in which neurons related to the transmission of ocular movements reside. Saccadic and vergence eye movements, used throughout our day to acquire visual information, were studied using eight control subjects who participated in four oculomotor experiments with fMRI. There are two main discoveries from this investigation. First, the activity with the brainstem for conveying signals to the cranial nerves can be observed via fMRI. Second, the pontine sites of the brainstem in humans contain not only saccade related signals but also vergence activity.