Decoding rapidly presented visual stimuli from prefrontal ensembles without report nor post-perceptual processing

Area of Science:

• Neuroscience
• Cognitive Science
• Primate Studies

Background:

• The role of the primate prefrontal cortex (PFC) in conscious perception remains debated.
• Global neuronal workspace theory predicts PFC neurons code conscious content.
• Previous studies used no-report paradigms to isolate conscious perception signals.

Purpose of the Study:

• Investigate PFC neuronal activity during challenged conscious perception.
• Determine if PFC encodes stimuli independent of post-perceptual processing.
• Compare PFC decoding with posterior parietal cortex (PPC).

Main Methods:

• Recorded neuronal ensemble activity from macaque ventrolateral PFC.
• Used isolated visual stimuli and rapid serial visual presentation (RSVP) paradigms.
• Decoded stimulus identity from PFC population activity.

Main Results:

• Stimulus identity was decodable from PFC activity even in RSVP conditions.
• PFC decoding peaked around 150ms post-stimulus onset.
• Decoding accuracy dropped significantly in RSVP after 200ms.
• Ventrolateral PFC showed stronger decoding than PPC.

Conclusions:

• Macaque PFC reliably encodes visual stimuli under challenging perceptual conditions.
• Findings support PFC's role in conscious experience, potentially beyond post-perceptual effects.
• Further research needed to differentiate conscious access from preconscious processing.