Neuroscience of consciousness
January 1, 2022
Joachim Bellet, Marion Gay, Abhilash Dwarakanath et al.
57 citations
Neuronal populations in the macaque prefrontal cortex (PFC) reliably encode visual stimuli even under conditions that challenge conscious perception and reduce post-perceptual processing. Recordings from the ventrolateral PFC during isolated trials and rapid serial visual presentation (RSVP) showed that stimulus identity could be decoded from population activity, with first signals at 60 ms and peak information at 150 ms. In RSVP, decoding accuracy dropped to chance by 200 ms as the next stimulus became decodable. Decoding in ventrolateral PFC was stronger than in posterior parietal cortex. The findings indicate PFC encodes visual information under conditions that limit conscious access and post-perceptual elaboration, raising questions about whether this reflects conscious access, phenomenal consciousness, or preconscious bottom-up processing.
bioRxiv Preprint Server
January 29, 2020
Abhilash Dwarakanath, Vishal Kapoor, Joachim Werner et al.
15 citations
preprint
Access of sensory information to consciousness depends on neural activity crossing a threshold in the prefrontal cortex (PFC), yet how brain state fluctuations interact with conscious content is unclear. Using multielectrode recordings during a no-report binocular rivalry task in animals, two distinct prefrontal states were identified: low-frequency (1-9 Hz) bursts that precede spontaneous switches in conscious perception (perceptual update), and beta-band (20-40 Hz) bursts correlated with stable perception. Beta bursts synchronize neural ensembles coding the perceived stimulus. Similar fluctuations occur during rest, suggesting they are endogenous. The findings indicate that global cortical states, not selective spiking, drive internal switches in conscious perception.
bioRxiv Preprint Server
January 28, 2020
Vishal Kapoor, Abhilash Dwarakanath, Shervin Safavi et al.
preprint
The prefrontal cortex can represent the contents of conscious perception even when no overt report is required. Recordings from macaque monkeys during binocular rivalry—where perception alternates between two conflicting images—showed that neural ensemble activity in the prefrontal cortex decoded which image the animal was seeing as accurately as when images were presented without competition. This decoding remained significant even when eye movements were suppressed, indicating that the signals were not solely due to oculomotor confounds. The findings suggest that prefrontal population dynamics reflect internally driven changes in conscious perception during multistable vision.