[Neurophysiological mechanism of brightness scaling]

A model of statistical decisions was used to reveal the measure of neural activity according to impulse reactions. Effectiveness of two possible measures was compared: number of spikes in groups and instantaneous frequency. The former one provides greater probability of correct estimation of brightness at a lesser error probability. Neurophysiological scales of brightness were obtained in the form of dependences of index d' on the stimulus intensity. The dependences were the power those in all cases of analysis. The exponent depends on the stimulus size and alters like the exponent of psychological scale for quantitative estimations on alteration of the stimulus space. The same dependence of subjective estimation on intensity of the light stimulut is preserved for psychophysiological scales of grouping on scaling by 5-, 10- and 20-grade scale of a single set of illuminations. This shows that the brightness neurophysiological scale formed at the first stage of perception is independent of the rules of decision making at the second stage of perception.