Summary: A new study revealed a physical phenomenon termed “informational tuning”: while the absolute volume of raw information transfer is surprisingly higher under anesthesia, the awake brain selectively channels information with high directional precision along the propagation axis of traveling waves.
This spatial sharpening of information transmission ensures reliable cortical communication during wakefulness, whereas anesthesia disrupts this tuning, drowning the brain in unstructured, noisy signal flow.
Key Facts
- Selective Directional Tuning: Information in the cerebral cortex flows selectively along the physical propagation direction of traveling waves, a property termed “informational tuning.”
- Precision Over Volume: The awake brain prioritizes signal reliability and directional precision over raw data volume. In contrast, the anesthetized brain exhibits higher overall transfer entropy but lacks directional organization.
- Wave Presence vs. Information Flow: The physical presence of propagating traveling waves alone does not guarantee structured information transfer; precise alignment between wave direction and transfer entropy is required for conscious processing.
- Mechanism of Anesthetic Loss of Consciousness: Anesthesia flattens the informational tuning curve, replacing crisp, vector-aligned cortical communication with noisy, isotropic signal propagation.
- Quantitative Metric for Consciousness: Combining biological wave mechanics with transfer entropy provides a mathematical benchmark for evaluating cortical communication efficiency across varying states of awareness.
Source: Kyoto University
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.
Simulation results revealed that the mere presence of traveling waves and their propagation does not guarantee information transfer. However, the scientists confirmed that information in the cerebral cortex flows selectively along the propagation direction of the traveling waves, a phenomenon they call informational tuning.
They observed that the resulting curves of this tuning are significantly sharper during wakefulness as compared to anesthesia. On the other hand, the researchers were intrigued to find that the absolute amount of transfer entropy was actually higher during anesthesia than in wakefulness.
“This unexpected finding suggests that while the anesthetized brain is flooded with random, noisy information, the awake brain selectively regulates information in specific directions,” says corresponding author Yutaka Komura. “In other words, the awake brain excels in the ‘reliability’ and precision of information communication, rather than just the raw quantity.”
By marrying the biological reality of traveling waves with the mathematical rigor of transfer entropy, this study demonstrates how the waking brain efficiently sharpens its internal communication to ensure reliable information flow, and provides a quantitative metric to evaluate the efficiency of information transmission between cortical regions.
But there is much more to uncover.
“Our future goal is to bridge the gap between our findings on informational tuning and deeper neural circuit mechanisms,” says Komura.
Key Questions Answered:
A: Traveling waves are coordinated, physical propagation events where electrical oscillations sweep across the surface of the cerebral cortex like ripples moving across a pond, coordinating communication across distant brain regions.
A: It was long assumed that anesthesia simply reduces or blocks information flow in the brain. Finding higher transfer entropy during anesthesia showed that the unconscious brain is actually flooded with random, unorganized signals, meaning consciousness depends on information precision rather than raw volume.
A: Informational tuning is the phenomenon where cortical information preferentially travels in the exact direction that physical traveling waves are moving. In the awake brain, this tuning curve is extremely sharp, focusing signal delivery to intended neural targets.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this consciousness and neuroscience research news
Author: Whitney Hubbell
Source: Kyoto University
Contact: Whitney Hubbell – Kyoto University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Awake cortex stabilizes traveling waves for global and reliable information routing” by Kaio Misawa, Koji Chinen, Akira Kawabata, Taro Kaiju, Takafumi Suzuki, Yutaka Komura. iScience
DOI:10.1016/j.isci.2026.116728
Abstract
Awake cortex stabilizes traveling waves for global and reliable information routing
How does the brain organize neural information for perception during wakefulness, yet lose such organization under anesthesia?
Theories on consciousness hypothesize that perceptual experience arises from global communication across the cerebral cortex. However, the neural substrate that mediates information transfer between cortical regions remains uncertain.
Here, developing large-scale and high-density electrocorticography arrays, we demonstrated that traveling waves serve as a fundamental mode for global information transfer. Compared with the anesthetized state, visual-evoked traveling waves during wakefulness exhibited greater stability.
Hierarchical clustering uncovered the emergence of widespread waves with a rich repertoire of motifs only in the awake state. By quantifying the fidelity of information routing, we found that information flows more reliably along the direction of wave propagation during wakefulness than under anesthesia.
This study provides meso- and macroscopic evidence consistent with theories of consciousness and introduces a framework, informational tuning, for characterizing the geometrical relations between neural and informational flows.
