Brain Mechanisms Subserving Self‐Generated Imagery: Electrophysiological Specificity and Patterning

The present study was designed to assess the patterning of occipital and sensorimotor EEG activation during self‐generated visual and kinesthetic imagery. Twenty subjects were requested to imagine, in separate trials, a flashing light, a tapping sensation on the right forearm, and both the light and the tapping together. Prior to the imagery trials, subjects were exposed to the stimuli which they were asked to subsequently imagine. EEG was recorded from the left occipital and left sensorimotor regions, filtered for alpha and quantified on‐line. The results indicated that self‐generated visual imagery elicited greater relative occipital activation than comparable kinesthetic imagery. The imagine‐both condition fell predictably in between the two unimodal imagery conditions. The difference between visual and kinesthetic imagery was primarily a function of greater occipital activation during the former versus the latter task. No difference in overall alpha abundance among the three imagery tasks was found. These findings suggest that the self‐generation of imagery in different modalities elicits specific changes in the sensory regions of the brain responsible for processing information in the relevant modalities.