[Role of the posterolateral nucleus of the cat thalamus in conducting peripheral and cortical polysensory influences].

The posterior lateral thalamic nucleus (LP) of the cat has separate inputs for ascending signals of different sensory and subcortical origin, as well as for cortifugal activity. With somatic stimuli, only non-specific and reticular signals come to LP. They are not directly involved in the genesis of evoked potentials (EP) in the parietal cortex (P) and the somatic zones I and II (SI and SII). With visual stimuli, specific and reticular impulses directly concerned with the formation of visual EPs in the P and the visual zone (VI) are projected to LP. The cortifugal action of VI, SI and SII influences the same modality in LP. The descending effect of P on visual and somatic signals in LP is actieved along autonomous pathways and consists in dissimilar types of direct (as in VI) and indirect (as in SI and SII) descending influences of different projection zones on impulses of the same modality in the given nucleus.