Decoding internally generated transitions of conscious contents in the prefrontal cortex without subjective reports

Abstract

A major debate about the neural correlates of conscious perception concerns its cortical organization, namely, whether it includes the prefrontal cortex (PFC), which mediates executive functions, or it is constrained within posterior cortices. It has been suggested that PFC activity during paradigms investigating conscious perception is conflated with post-perceptual processes associated with reporting the contents of consciousness or feedforward signals originating from exogenous stimulus manipulations and relayed via posterior cortical areas. We addressed this debate by simultaneously probing neuronal populations in the rhesus macaque (Macaca mulatta) PFC during a no-report paradigm, capable of instigating internally generated transitions in conscious perception, without changes in visual stimulation. We find that feature-selective prefrontal neurons are modulated concomitantly with subjective perception and perceptual suppression of their preferred stimulus during both externally induced and internally generated changes in conscious perception. Importantly, this enables reliable single-trial, population decoding of conscious contents. Control experiments confirm significant decoding of stimulus contents, even when oculomotor responses, used for inferring perception, are suppressed. These findings suggest that internally generated changes in the contents of conscious visual perception are reliably reflected within the activity of prefrontal populations in the absence of volitional reports or changes in sensory input.

Representing experience over time: sustained sensory patterns and transient frontroparietal patterns

“…However, unlike pure no-report paradigms, here the subjects had to decide whether the stimulus belonged to a target category or not, implying that our findings may still be related to task requirements. Nevertheless, our findings are unique in showing stimulus specific representations which are not mapped to task distinctions (see recent findings in monkeys in 82,83 ). That is, we find highly accurate decoding between image categories that are both non-targets, and which do not share any low-level properties with the target stimuli (e.g., face and watches).…”

Conscious Perception and the Prefrontal Cortex A Review

“…A more recent study using intracranial recordings in monkeys did find neural activity in PFC representing the conscious stimulus during binocular rivalry alternations in a no-report paradigm (Kapoor et al 2022). Block (2020) noted that post-perceptual cognition could account for this result: "subjects whose only task is fixating a dot may have thoughts about the noticeably different stimuli, causing prefrontal differences" (p.1).…”

Awareness and consciousness in humans and animals – neural and behavioral correlates in an evolutionary perspective

“…In such recordings, NCCs of three neural processes may be identified ( Aru et al, 2012b ; de Graaf et al, 2012 ; Li et al, 2014 ) – those preceding or leading to the conscious experience, those representing the conscious experience, those following the conscious experience (e.g., the report about the experience). In order to separate NCCs of awareness (domain (a), see Introduction) from those of following conscious actions (domain (b), see Introduction), several experiments without or with modified/controlled task requirements have been reported in studies on humans (e.g., Pitts et al, 2014b ; Tsuchiya et al, 2015 ; Koivisto et al, 2016 ; Ye et al, 2019 ; Cohen et al, 2020 ; Mazzi et al, 2020 ; Rowe et al, 2020 ; Faramarzi et al, 2021 ; Schröder et al, 2021 ) and also in a recent study on macaque monkeys ( Kapoor et al, 2022 ).…”