1/ We discovered something totally unexpected about the neural structure of consciousness that overturns decades of thinking on its biological basis and brings us significantly closer to the recipe for generating conscious awareness.
New preprint: biorxiv.org/content/10.648… (led by @HesseJanis, with @FrankLanfranchi, @_conor_mcgrory, @Yuelin_Shi, and @EngelTatiana)
New preprint: biorxiv.org/content/10.648… (led by @HesseJanis, with @FrankLanfranchi, @_conor_mcgrory, @Yuelin_Shi, and @EngelTatiana)
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2/ TL/DR: We found neural activity across both inferotemporal and prefrontal cortex alternates between a conscious mode and an unconscious mode ~ 15 times every second.
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3/ Bistable illusions like the face-vase illusion provide a powerful window into consciousness. They suggest that conscious awareness is the result of an active process in which the brain selects one interpretation to reach awareness out of all possible ones.
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4/ To study how this works, we used binocular flash suppression: in this paradigm, two different images are shown to the left and right eyes, and we can fully control which image is consciously perceived and which remains unconscious.
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5/ We recorded responses from thousands of neurons in inferotemporal and prefrontal cortex using Neuropixels probes while presenting thousands of flash suppression stimulus pairs. We found that neural activity rapidly alternates between two coordinated states.
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6/ Remarkably, when we reconstructed the image using neural activity from one of the states, it looked exactly like the conscious face, and when we did the same from the other half of time, it looked exactly like the suppressed face. This means that just from neural activity, we detail not only something that you consciously perceive, but also something that escapes your awareness.
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7/ These findings show that representation of conscious and suppressed content alternates every ~ 60 ms. Thus conscious perception does not reside in a specific brain region, but rather a specific temporal phase.
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8/ At the single-neuron level, we found that cells concertedly switched their tuning every 60 ms, from representing the conscious face to the suppressed face. Thus the same population of neurons represent both what you’re aware of and what you’re not, at different moments of time.
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9/ Personal note: For almost a decade, @HesseJanis and I have been struggling to resolve the discrepancy between the classic story reported in textbooks that anterior parts of the brain contain a pure representation of conscious awareness, and the reality that the neurons Janis dn’t reflect this: modulation by conscious awareness during rivalry was stubbornly weak.
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@HesseJanis 10/ This raised a gnawing puzzle: how could the neural correlate of consciousness appear so weak everywhere we looked, when conscious perception during rivalry is so clear? We were trapped in our expectations. But the brain didn't care…
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@HesseJanisd to jump for joy when Janis showed me the reconstructions. At last, we had found a pure correlate of conscious awareness in the brain during rivalry that matched the clarity of conscious perception. He had solved the puzzle. And once again, the truth is always the most interesting:
Oct 17, 2026 · 6:02 AM UTC
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@HesseJanis most exciting is that we have uncovered a signal deep in the brain that richly represents a stimulus you’re not aware of. This finding, in my opinion, makes it tractable to understand how a pattern of neural activity accesses consciousness. The previous dominant idea--that suppressed stimuli become progressively weaker as you go anterior (“fail to ignite”)--left the question of how a representation becomes consciously accessible extremely hard to pin down. Whereas now, with whoppingly clear signals corresponding to both what is and isn’t conscious, we can follow both sets of footprints, to track down the full machinery for generating conscious percepts.
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The outpouring of interest in our paper has been … a bit insane.
May I make four points?
1. We have not shown that “consciousness has a frame rate.”
I can see why people draw this conclusion: we report that inferotemporal and prefrontal cortex alternate between conscious and suppressed states roughly every 60 ms during binocular rivalry.
Consciousness depends on many brain areas, and our paper reports results from only a few select nodes.
We still don’t know how conscious access works--the actual recipe for generating conscious experience. What we have shown is that deep in the brain there is an extremely strong signal, rich enough to reconstruct a high-dimensional face in detail, that is inaccessible to consciousness. As I argued in the original tweet, this makes the problem of conscious access a lot more experimentally tractable. But to claim “consciousness has a frame rate,” one would need to have actually solved the mechanism for conscious access and shown that this mechanism operates at a frame rate.
While we currently don’t know conclusively one way or the other (see VanRullen & Koch, 2003 for a review of positive evidence), I personally am skeptical that consciousness has a frame rate. I believe the brain, within posterior parietal cortex, has continuous tracking mechanisms that actively represent the persistence of matter, including ourselves as physical bodies. The coupling between these persistent tracking processes and feature representations across the brain (like those in face patches) is, I think, the essential mechanism of conscious access.
This coupling need not happen at the rate of inferotemporal alternations (and inferotemporal cortex itself may not even alternate outside of the artificial situation of binocular rivalry). As an analogy: imagine the area crucial for conscious access holding a steady drone note, while inferotemporal cortex alternates between two notes, one in harmony and one dissonant. Inferotemporal content might couple to the drone only at moments of harmony, yet experience would still be continuous, because the drone itself (the tracking process that I believe is at the core of conscious perception) never stops. And areas without conflicting content, like auditory cortex during visual rivalry, could stay in continuous harmony with the drone.
In sum, there is no reason to conclude from our study that consciousness is discrete, with a "frame rate."
2. Our results resemble Jezek et al. 2011 (as @jjsakon notes).
Jezek et al. trained rats in two boxes that were identical except for their lighting cues, so that hippocampal place cells formed two distinct maps, one per box. They then “teleported” the rat by abruptly switching the lights. For a few seconds afterwards, CA3 place-cell activity flickered between the two maps, synced to the theta cycle (~125 ms).
@StanDehaene first pointed this paper out to me, and reading it blew me away. To my mind it is the strongest evidence for a bistable attractor in the brain, because the competing maps are stored within the hippocampus itself.
I think the phenomenon we see may be very similar at the circuit level: a bistable attractor network within inferotemporal cortex that alternately converges to one of two patterns, as cells in face patches work together to build a coherent representation of the input. In our case, both images are present in the input, so the competition could arise within IT or be inherited from earlier areas such as V1--recording there is an important next step. (It also still puzzles me that we didn’t see strong coherence between face patches ML and AM.)
More broadly, what’s different about our paper is the brain area (inferotemporal cortex, often modeled as a feedforward DNN) and the ability to relate the two competing patterns to consciousness, with one granted conscious access and the other not.
3. Please comment on bioRxiv!
The Twitter attention has been cool, but I really hope colleagues will be generous enough to post detailed commentary on bioRxiv, where there are currently 0 comments. As @seemaychou points out, peer review doesn’t have to come from just three anonymous reviewers. We would be truly grateful for your critical feedback.
4. Stay tuned
This work was done at Caltech, Berkeley, in collaboration with @EngelTatiana at Princeton, funded by NIH and HHMI.
I hope to share our vision soon for how we can solve consciousness @AsteraInstitute
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