Occipital MEG Activity in the Early Time Range (<300 ms) Predicts Graded Changes in Perceptual Consciousness.
Cerebral cortex (New York, N.Y. : 1991) June 1, 2016 Lau M Andersen, Michael N Pedersen, Kristian Sandberg et al.
Two brain signals have been studied as possible markers of conscious perception: an early one from the back of the head (130-320 ms after seeing something) and a late one from the front (320-510 ms). Recent work suggests the late signal may also reflect expectations, attention, and task demands, not just consciousness. Using magnetoencephalography and multivariate decoding, this study directly compared how well each signal predicts whether someone consciously perceives a stimulus. Occipital (back-of-head) sources in the early time window were significantly more accurate at decoding consciousness than frontal sources in either time window. These results challenge theories that emphasize frontal brain regions for conscious perception.