TMS, phosphenes and visual mental imagery: A mini-review and a theoretical framework

Abstract

We reviewed the existing research linking visual mental imagery and phosphenes induced by TMS. We examined and contrasted conditions (and parameters) under which intensity and amplitude of TMS application at various cortical sites along the ventral and dorsal visual pathways: 1) induces the experience of visual images during perception and mental imagery, 2) interferes with or facilitates perception and/or imagery in concurrent and dual task conditions, 3) correlates with self-reports such as vividness ratings, and 4) reduces or has other selective effects on phosphene threshold in concomitance with perception and imagery. We propose an interpretation of the results of this mini-review within a new biophysical framework for visual mental imagery based on Bokkon’s redox molecular model of explicit optical coding of visual information in early visual areas (V1) and the propagation of conscious visual content at other levels in the stream of visual processing and in other parts of the brain.