StimConscious · The role of subcortical structures in perceptual consciousness: a causal investigation

The investigation of the neural substrates of perceptual consciousness has mainly relied on correlative analyses of brain activity. Additionally, subcortical structures — which have long been believed to play a role in perceptual consciousness — have been understudied. StimConscious proposes a new, causal line of research to test the hypothesis that a transient arousal pulse from subcortical structures facilitates cortical processes that are necessary for consciousness. Electrical pulses will be delivered with precisely controlled timing during a well-validated visual detection task, in which face stimuli are presented to human participants at their perceptual threshold. In WP1, I will investigate how the timing and anatomical location of non-invasive neurostimulation of subcortical structures affect behavioral markers of perceptual consciousness. In WP2, I will test if direct, invasive neurostimulation of the central thalamus concurrent with stimulus presentation impacts those markers. In both WPs, I will investigate how neurostimulation of subcortical structures influences cortical signals associated with perceptual consciousness. StimConscious will generate a unique dataset from a population of epilepsy patients with rare thalamic implants. These findings will be complemented by a cutting-edge, non-invasive method in healthy participants — temporal interference stimulation — that expands neurostimulation targets beyond the central thalamus to include the midbrain and cerebellum. For the first time, StimConscious will directly test if perception of a stimulus is facilitated by a pulse of activity in subcortical structures. The proposed project therefore promises to unravel the role of subcortical structures in perceptual consciousness, moving beyond correlations to establish causal explanations.