Widespread, perception-related information in the human brain scales with levels of consciousness

Abstract

How does the human brain generate coherent, subjective perceptions--transforming yellow and oblong visual sensory information into the perception of an edible banana 1? This is a hard problem. The standard viewpoint posits that anatomical and functional networks integrate local, specialized processing across the brain to somehow construct unique percepts. Here, we provide evidence for a novel organizational concept by uncovering task-specific information distributed across the human brain. First, we show that functional magnetic resonance imaging (fMRI) can uncover task-specific information throughout the neocortex, even across voxels traditionally discarded as "noise" (t-statistics {approx} 0), challenging the sensitivity of traditional linear, univariate analytical approaches. Remarkably, task-specific signals could also be uncovered from across-subject variances and were ubiquitous even in the subcortex and cerebellum. Finally, we show that the widespread signal in regions remote from a tasks primary and secondary sensory cortices depends on the level of sedation, suggesting it is related to perception{dagger} rather than sensory stimulus encoding. We hypothesize that these widespread, task-specific, and consciousness level-dependent signals may be the basis for coherent, subjective perceptions.