Evidence for an Active Role of Inferior Frontal Cortex in Conscious Experience

Despite a growing understanding of human brain function, it is still unclear how conscious experience emerges from neural activity. A much-debated question in the search for the neural underpinnings of consciousness is whether prefrontal cortex actively shapes conscious experience or, alternatively, serves only complementary cognitive functions such as evaluating and acting on the contents of consciousness. Here, we studied the neural mechanisms of bistable perception to elucidate the role of prefrontal cortex in consciousness. Human participants reported periodic changes in conscious experience that were induced by conflicting sensory information. Two functional magnetic resonance imaging experiments showed that prefrontal brain activity in inferior frontal cortex signals the conflict between conscious experience and available sensory information. In a third experiment, inhibitory transcranial magnetic stimulation revealed that a disruption of neural activity in inferior frontal cortex leads to a decrease of conflict-driven changes in conscious experience. Our results indicate that, by engaging in iterative and reciprocal interactions with sensory brain regions, inferior frontal cortex plays a critical role in both the detection and the resolution of perceptual conflicts. This points to a causal influence of prefrontal brain activity on the dynamic unfolding of conscious experience.