Spiking the mind: Rethinking the role of cortical feedback in visual mental imagery.

Abstract

Recent research has revealed similarities between visual mental imagery and visual perception. Visual imagery is supported by cortical feedback involving multiple visual areas, including the primary visual cortex, and functionally interacts with perception. This has led to the assumption that imagery is “perception in reverse,” with feedback connections driving action potentials in early visual areas. However, evidence on feedback mechanisms is mixed, often exerting modulation (often as negative gain control) in sensory areas. Here, we examine and interpret the current understanding of feedback mechanisms related to visual imagery, integrating this with its functional effects and neural correlates. Finally, we put forward a new hypothesis, along with testable predictions, proposing that imagery reshapes spontaneous neural activity rather than producing spiking in early visual areas. This new framework explains many of the properties of visual imagery while providing a better general understanding of feedback and brain function.