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Recording of averaged evoked potentials to two successive visual stimuli shows that associations, temporary connections, direct and feedback, can be elaborated in man between two unrecognized stimuli. The magnitude of cortical late response to the first stimulus in the complex diminishes as a result of action of the inhibitory feedback temporary connection. This inhibitory effect is more pronounced when the second stimulus is emotionally significant for the subject. The evoked potential to the second stimulus in the association between unrecognized visual stimuli is considerably facilitated. The role is discussed of direct and feedback temporary connections between unrecognized stimuli in some unconscious psychic phenomena in man.

Averaged evoked potentials (AEP) to verbal (letters) and nonverbal (random shapes) stimuli exposed in the left and right visual fields were registered in healthy subjects with normal vision. Analysis of the later AEP latencies pointed to asymmetry in the temporal parameters of the interhemispheric interaction. The late AEP latency is shorter in the right hemisphere than in the left hemisphere. The difference is more pronounced in responses to nonverbal stimuli. The earlier development of the evoked potential in the right hemisphere (or the later one in the left hemisphere) accounts for the interhemispheric difference in the temporal parameters of the late AEP components. Comparison of the latency of the component P300 to verbal and nonverbal stimuli presented in the ipsilateral or the contralateral visual fields reveals a transfer of the results of the cortical processing of visual information in the course of interhemispheric interaction.