[Dynamics of evoked potentials at different points in the cat somatosensory cortex during elaboration of conditioned...

In chronic experiments on cats a study was made of the spreading of evoked potentials (EP) in the somatosensory zones S1 and S2 in response to biologically significant tonal stimuli. The formation of conditioned connections enhances the capacity for polysensory reactions in different cortical somatic fields outside the zones of local projection of the unconditioned stimulus. As stable conditioned connections are formed, this capacity diminishes in relation to reinforced and, particularly, easily differentiated sounds: EP are more localized in response to the former, and disappear altogether when the latter are presented. The wide EP spreading in zones S1 and S2 is the longest in response to medium and fine differentiation tones, which points to the involvement of these zones in the integrative analysis of signals by their biological quality.