The frontal eye fields target multisensory neurons in cat superior colliculus

While sensory corticotectal connections have received considerable attentio n, relatively little is known about the nature of superior colliculus neuro ns that receive input from the cortical frontal eye fields. The present exp eriments used microstimulation of indwelIing electrodes in the frontal eye fields and single-unit recording in the superior colliculus to demonstrate that frontal afferents preferentially terminate on multisensory neurons in the colliculus. Furthermore, the medial and lateral subdivisions of the cat frontal eye fields access physiologically distinct populations of multisen sory collicular neurons. Specifically, the medial subdivision preferentiall y activates neurons with visual and auditory sensory responses located medi al within the colliculus, while the lateral subdivision preferentially acti vates collicular neurons with visual and somatosensory responses found more laterally. These data support reports distinguishing the medial and latera l subdivisions of the frontal eye fields in the cat and suggest that signal s from each may route separately through the colliculus to induce or coordi nate different components of gaze control.