The frontal eye fields target multisensory neurons in cat superior colliculus

While sensory corticotectal connections have received considerable attention, relatively little is known about the nature of superior colliculus neurons that receive input from the cortical frontal eye fields. The present experiments used microstimulation of indwelling 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 multisensory collicular neurons. Specifically, the medial subdivision preferentially activates neurons with visual and auditory sensory responses located medial within the colliculus, while the lateral subdivision preferentially activates collicular neurons with visual and somatosensory responses found more laterally. These data support reports distinguishing the medial and lateral subdivisions of the frontal eye fields in the cat and suggest that signals from each may route separately through the colliculus to induce or coordinate different components of gaze control.