Physiological correlates of individual differences in decision-making time during purposeful mental activity in humans

EEG correlates of individual differences in decision-making time were studied in subjects performing the task of memorizing and subsequently reproducing, on a monitor screen, a sequence of signals. Forty-six students were volunteers in the study, carried out with the use of an original computer-aided technique. Pioneering data on the individual specificity of physiological processes underlying human mental activity were obtained. Individual differences in EEG characteristics related to differences in the temporal parameters of the decision-making stage were found. In a situation directly preceding the activity, subjects characterized by a short decision-making time exhibited higher powers of the Δ (in the occipital, parietal, and central cortical areas) and θ-(in both the central and the right frontal and temporal areas) EEG rhythms. The subjects with a short decision-making time differed from those with a long decision-making time in a higher power of the θ rhythm in the right temporal area during memorization and an increased θ rhythm power in the frontal areas during reproduction of a signal sequence.