Organized when awake, chaotic when not
Kyoto UniversityPeer-Reviewed Publication
Kyoto, Japan -- How and why we experience consciousness is a question that has long plagued philosophers and scientists alike. We have come to understand that when awake our brains organize neural information for perception, yet we completely lose this organization under anesthesia. Why this happens is a longstanding mystery in neuroscience, as simple changes in the activity levels of specific brain regions fail to explain this disappearance of consciousness.
Theories have hypothesized that conscious perception arises from two core pillars: the brain's ability to encode external features, and its ability to transmit information across different cortical regions. While the former has been well-supported, direct physical evidence of the latter has remained elusive. A team of researchers at Kyoto University set out to bridge this critical gap between neural signals and information dynamics.
The team developed arrays for high-density custom electrocorticography -- or ECoG -- that covered most of the cerebral cortex of a rat's right hemisphere. This allowed them to extract traveling waves, physical phenomena in which electrical activity propagates across the brain like ripples in a pond. The scientists then analyzed these signals in simulations with transfer entropy, a mathematical metric that quantifies the directional flow of information. This approach allowed the team to investigate how tightly the neural signals and informational flows are linked.
- Journal
- iScience
- Funder
- Japan Science and Technology Agency, Japan Society for the Promotion of Science, Naito Foundation