Polysensory properties of the horizontal region of the diagonal bundle from the cat forebrain

Sharply different wave forms and parameters of averaged evoked potentials (EP) in response to single visual and somatic stimuli were observed in the same points of the horizontal limb nucleus of the diagonal band (NDB) in cats under nembutal anesthesia. The existence of heterogenic EPs in NDB makes it possible to consider this part of the nucleus as a polysensory structure. Decreased EP latency, as compared to that in the neocortex, indicates that heterogenic impulses reach NDB by higher speed Ways than the cortex. The comparison of NDB EP refractory periods during paired stimulation of one or different sensory systems shows that polyvalent impulses affect independently functioning neuronal populations. It is suggested that a common principle of specific heterogenic signals arrival to distinct neuronal complexes exists for polysensory structures at different levels of the central nervous system.