Abstract
A significant problem in neuroscience concerns the distinction between neural processing that is correlated with conscious percepts from processing that is not. Here, we tested if a hierarchical structure of causal interactions between neuronal populations correlates with conscious perception. We derived the hierarchical causal structure as a pattern of integrated information, inspired by the integrated information theory of consciousness. We computed integrated information patterns from intracranial electrocorticography from 6 human neurosurgical patients with electrodes implanted over lateral and ventral cortices. During recording, subjects viewed continuous flash suppression and backward masking stimuli intended to dissociate conscious percept from stimulus, and unmasked suprathreshold stimuli. Object-sensitive areas revealed correspondence between conscious percepts and integrated information patterns. We quantified this correspondence using unsupervised classification methods that revealed clustering of visual experiences with integrated information, but not with broader information measures including mutual information and entropy. Our findings point to a significant role of locally integrated information for understanding the neural substrate of conscious object perception.
Significance Statement What is the link between neural activity and conscious experience? It is clear that experience is generated in the brain, as conscious experience occurs even without sensory inputs, but it is also clear that not everything that occurs in the brain is correlated with consciousness. There must be some phenomenon occurring in brains that is critical for consciousness. In this paper we tackle this issue from a new direction: starting from conscious phenomenology, we derive a novel measure of distributed population neural activity – the integrated information pattern – and find that, when applied to intracranial field potential recordings (ECoG), this measure can be used to classify the conscious perceptual experiences of human subjects.
Footnotes
The authors declare no conflict of interest.
AMH was supported by an Endeavor Fellowship from the Australian Department of Education. CK, HK, HO, and MAH were supported by NIH grants R01 DC004290 and UL1RR024979. NT was supported by the Future Fellowship (FT120100619) and the Discovery Project (DP130100194) from the Australian Research Council.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
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