[Mechanisms regulating perception: regulation of sensation].

The slow electrical activity of the thalamic region of the cortex, as well as the psychophysical characteristics of perception were registered in experiments on discerning light flashes in brightness in healthy probands, excitable psychopathic subjects and schizophrenic patients (simple form with apatho-abulic manifestations). It is shown that correct perception of the light flashes depends on stabilization of the thalamic region potentials in the time intervals of 100 to 200 msec following immediately the stimuli. In cases of erroneous perception no stabilization of such kind was noted. A certain relationship between the perception characteristics and the time course of the slow electrical activity on the one hand, and the proband's intention to select pairs of flashes of different or equal intensity as the signal was registered. As a result, in cases of correct perception of the signal pair of the flashes the stabilization of the slow potential was more marked than in cases of perceiving non-signal pairs. This fact points to an active character of the physiological regulation of the visual analyzer sensitivity.