Based On No-report Paradigm To Investigate The Neural Correlates Of Visual Consciousness

Being conscious means,someone is having subjective experiences,which is a special phenomenon that emerges from cognitive activities.The minimum neuronal mechanisms jointly sufficient for any one specific conscious experience is called Neural Correlates of Consciousness(NCC).Existing theories of consciousness mostly suggest that NCC has some sort of recurrent or feedback neural mechanism,but there are different predictions about the brain regions involved.Predictions of different theories have been verified experimentally independent,but there are few comparative studies of different theories in the same experiment.In addition,some theories focus on phenomenal consciousness,while others focus on access consciousness,and these two kinds of consciousness may have different NCC.In this study,we combine the no-report experimental paradigm,starting with visual consciousness and using functional magnetic resonance imaging to explore the differences between phenomenal and access consciousness of NCC in the same experiment,and compare the predictions of different theories of consciousness.The study found that:(1)The univariate results obtained NCC candidate brain regions similar to those in previous studies,including the primary visual cortex,lateral occipital complex,inferior parietal sulcus,and inferior frontal gyrus.(2)The multi-voxel pattern analysis of the candidate NCC revealed that brain regions under unconsciousness could not decode stimuli with shapes;the inferior parietal sulcus in phenomenal consciousness could decode stimuli with shapes stably;only the activation pattern of the frontoparietal lobe could decode with or without shapes stably when the conscious content was task-related but not the target;a wide range of brain regions could decode effectively under access consciousness when the conscious content was the target.(3)The results of the dynamic causal model showed that network connectivity did not change significantly under unconsciousness;the involvement of the visual cortex and the parietal lobe are key to generating phenomenal consciousness;and both the visual cortex and the frontoparietal lobe played an important role under access consciousness,and the inferior frontal gyrus suppressed the activity of other brain regions when the content of consciousness was task-related but not the target.In summary,the neural correlates of phenomenal consciousness are more likely toward posterior brain regions with the parietal lobe as the core;the neural correlates of access consciousness are more likely toward anterior brain regions with the frontoparietal lobe as the core,and in addition the generation of target access consciousness ignites the global network,but no global ignition is observed for non-target access consciousness.It is thus clear that different theories explain consciousness with respect to a different aspect of consciousness,and that the conflicting experimental results between them are not only related to the experimental design but also influenced by the different definitions of consciousness.Subsequent research on consciousness should maintain a consistent definition of consciousness while comparing multiple theories within the same experiment,in addition to considering the different implications of different relationships between consciousness content and task targets.