Reflection of decision making in cortical evoked activity

1. The amplitude of the late positive potential (P300) to a visual stimulus is essentially increased at the vertex if informational value is attached to the stimulus with respect to making a decision concerning the choice of response. In the occipital region no such changes are observed. 2. In cases with decision making the amplitude of the P300 component is clearly greater at the vertex than in the occipital region. 3. No correlation was found between the latent periods of the P300 wave and the motor response to a visual stimulus. 4. The P300 component of AEP, in the writers' opinion, reflects not the process of decision making itself, but local cortical (nonspecific) activation, which is an essential element in the neural mechanisms of decision making.