Responses of neurones of the pontine nuclei to stimulation of the sensorimotor, visual and auditory cortex of rats.

The aim of this study was to investigate the degree of convergence of corticofugal neurones from various cortical areas onto single neurones of the pontine nuclei (PN). Eighty-five% of the PN neurones responded to electrical stimulation of at least one of the following cortical areas: sensorimotor, visual, auditory. Slightly less than half of these neurones displayed a convergent input from two or three of functionally different cortical areas. The sensorimotor cortex, particularly the face areas, provided the most important input to the PN; stimulation of the visual cortex was less effective and stimulation of the auditory cortex rarely excited PN neurones. The electrophysiological results suggest that considerable cross-link exists between the anatomically defined cortico-pontine projection columns.