Visual Awareness

Abstract

Human vision gives rise to subjective experience of the external world. Vision depends on signals and processing within the central nervous system, yet it is apparent that not all activity associated with vision reaches awareness. For example, the state of a single photoreceptor in the retina cannot be directly reported, even though that receptor processes sensory information that contributes to perception. Processing of visual signals can therefore occur in the absence of awareness, and a central question in the neurobiology of consciousness is which neural signals and psychological processes in the brain are correlated with visual awareness and which remain unconscious. Qualitatively and quantitatively dissociating brain activity associated with conscious and unconscious vision will reveal the neural correlates of visual awareness. This chapter will review the current state of progress in understanding the neural signals underlying human visual awareness, with a particular focus on work carried out in the last five years.