How can the rich stream of visual sensations we experience can emerge from brain dynamics? We tackle this enduring question by considering two different constraints on brain dynamics: the architecture of the visual system on the one hand, and the influence of internal bodily signals on ongoing large-scale brain activity.
The idea that the architecture of the visual system constrains visual perception is certainly not new, but it is surprisingly often overlooked in the literature on visual consciousness. We attempt at bridging the gap between those two fields. Our hypothesis is that the initial feedforward sweep of visual processing leads to the emergence at the top of the visual hierarchy of the first global conscious appraisal of the visual input, giving rise to meaningful but not detailed visual experience. Depending on cognitive goals, conscious visual percepts would later be enriched by details encoded at lower levels of the visual hierarchy. This hypothesis can potentially reconcile two different theoretical views on consciousness, one that insists on the importance of subjective experience and the other one that insists on the tight link between consciousness and cognitive functions. We are currently developing new stimuli and paradigms to experimentally probe the validity of this hypothesis.
The second line of research developed in the Visual Cognition group is rooted on the fact that spontaneous fluctuations of ongoing large-scale brain dynamics can have a profound impact on how we perceive visual stimuli. We currently develop and test the hypothesis that neural responses to signals from visceral organs, such as the heart or the gut, that are constantly relayed up to the neocortex, shape ongoing large-scale brain dynamics and in turn impact visual consciousness and visual cognition. We further propose and test the hypothesis that neural maps of the internal state of the body could constitute a neural referential from which first person experience can be created.