What has TMS taught us about the role of V1 in conscious and unconscious processing?

There exist different theories of the neural mechanisms underlying visual awareness about the role of the primary visual or striate cortex (V1) in conscious and unconscious vision. Transcranial magnetic stimulation (TMS), a technique capable of disrupting cortical activity transiently and reversibly, has been increasingly used to investigate whether V1 activity is necessary for conscious and unconscious perception. The chapter provides a critical review of the different experimental procedures that have been applied in exploring this issue using TMS, summarizes the findings that they have generated and highlight directions for future research.