[Participation of interoceptive afferent excitations in sensory integration processes of cat visual cortex neurons]

In experiments on cats immobilized with diplacine it is shown that stimulation of the vagal and splanchnic nerves exerts a substantial influence on the neuronal background activity of field 17 in the brain cortex. Neuronal responses as prolonged tonic changes in impulse frequency were seen more often. Complex phasic neuronal responses with steady inhibitory periods and periods of activation appeared more rarely. The development of phasic reactions could begin both with activation and initial inhibition of the activity. Predominantly excitatory responses resulted from the splanchnic nerve stimulation. They could be also seen during somatic stimulations. The degree of neuronal involvement into the responses and their intensity increased by trains of stimuli. Visceral and somatic influences on the visual cortical neurons are shown to be mediated by the lateral hypothalamus and midbrain reticular formation.