The involvement of the human prefrontal cortex in the emergence of visual awareness.

Summary

Saccadic latency is significantly shorter in aware trials compared to unaware ones, highlighting the prefrontal cortex's (PFC) crucial role in visual consciousness. In a study involving six patients, local field potential data revealed early awareness-related activity in the PFC, peaking at 200-300 milliseconds. Neural patterns related to awareness were not static but dynamically changed over time. Enhanced connectivity between the PFC and other brain regions during early awareness trials suggests a complex mechanism underlying conscious access, emphasizing the PFC's importance in human awareness.

Abstract

Exploring the neural mechanisms of awareness is a fundamental task of cognitive neuroscience. There is an ongoing dispute regarding the role of the prefrontal cortex (PFC) in the emergence of awareness, which is partially raised by the confound between report- and awareness-related activity. To address this problem, we designed a visual awareness task that can minimize report-related motor confounding. Our results show that saccadic latency is significantly shorter in the aware trials than in the unaware trials. Local field potential (LFP) data from six patients consistently show early (200-300ms) awareness-related activity in the PFC, including event-related potential and high-gamma activity. Moreover, the awareness state can be reliably decoded by the neural activity in the PFC since the early stage, and the neural pattern is dynamically changed rather than being stable during the representation of awareness. Furthermore, the enhancement of dynamic functional connectivity, through the phase modulation at low frequency, between the PFC and other brain regions in the early stage of the awareness trials may explain the mechanism of conscious access. These results indicate that the PFC is critically involved in the emergence of awareness.

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