[Reflection of the decision making process in evoked cortical electrical activity in man]

Averaged evoked potentials to visual stimuli of different significance were recorded in healthy adult subjects. The magnitude of the late positive potential (component P300), recorded in response to visual stimulus, greatly increases at the vertex, if the stimulus is given a significance for decision making (the choice of reaction). No such changes are recorded in the occipital area. In the case of decision making, the magnitude of the component P300 is clearly greater at the vertex as compared with the occipital area. No correlation has been found between the latency of the P300 and the reaction time, hence one should not refer to any coincidence between the temporal parameters of the potential and the process of decision making. The authors believe that the component P300 reflects not the very process of decision making, but a local cortical "non-specific" activation which is an indispensable element of the neural mechanism of decision making.