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György Buzsáki:
When we speak about brain rhythms, we are not indulging in metaphor but describing the very language of the brain. Every thought, every memory, every spark of awareness is carried on oscillations. Among these, the 40 Hz gamma rhythm holds a special fascination. It is fast, fragile, and yet seemingly central to how neurons coordinate across vast networks.
For decades, neuroscientists have debated: is gamma simply a byproduct of neural firing, or is it a binding force that makes perception and consciousness possible? My research, and that of many colleagues here, suggests it is both a signature and a scaffold. Gamma synchrony provides the temporal tags that allow distributed neurons to work together, binding information into coherent wholes. Without rhythms, neural activity would be like an orchestra tuning endlessly, never producing music.
Today, we stand at a crossroads. Gamma waves are not only of theoretical interest; they have entered the realm of therapy. Experiments in mice and humans show that 40 Hz stimulation can reduce Alzheimer’s pathology, improve memory, and restore elements of cognition. This is extraordinary, but it also demands humility. For every promising result, there are deeper questions: can rhythms heal the brain, or only support it? Can we entrain consciousness itself, or only its neural signatures?
In this roundtable, we will explore five dimensions of gamma: its role in consciousness, its potential to heal, its entanglement with technology and ethics, its dialogue with other rhythms, and its philosophical implications. My task in this introduction is simple: to remind us that rhythms are not decorations on top of neural activity. They are the foundation of communication within the brain. To study 40 Hz gamma is to study the very syntax of thought.
And yet, syntax is not meaning. The rhythm alone does not explain why the lights of consciousness turn on. That mystery remains. But if we can understand gamma, harness it, and learn to protect it, perhaps we can move closer to answering not only how the brain works, but what it means to be alive and aware.
(Note: This is an imaginary conversation, a creative exploration of an idea, and not a real speech or event.)
Topic 1: Gamma Rhythms and Consciousness — Are 40 Hz Waves the Seat of Awareness?
David Chalmers (Moderator):
When philosophers talk about consciousness, we often wrestle with the hard problem — why subjective experience arises at all. Neuroscientists, on the other hand, point to rhythms, connectivity, and physiology. Let’s begin here: is the 40 Hz gamma rhythm causally essential to consciousness, or is it just correlated with it?
Question 1: Is 40 Hz gamma causally tied to consciousness?
György Buzsáki:
We should be careful not to mistake the rhythm for the orchestra. Gamma oscillations emerge from networks of inhibitory interneurons. They coordinate neural firing, yes, but coordination is not equivalent to consciousness. You can have gamma without awareness — anesthesia can produce gamma-like bursts. What matters is not the frequency per se, but the way rhythms scaffold communication across brain regions.
Li-Huei Tsai:
In our lab, we see 40 Hz rhythms as not just noise, but as a potential driver. When we induce gamma in mouse models of Alzheimer’s, we see structural changes — microglial activation, reduced amyloid. If rhythms can rewire the biology of the brain, why not also aspects of consciousness? It may not be sufficient alone, but perhaps it is necessary.
Christopher Moore:
I side with caution. Gamma is clearly involved in perception — we’ve shown that neurons synchronize more strongly when animals become aware of a stimulus. But gamma appears in unconscious processing too. I’d argue it is more like a marker of “information binding.” Awareness likely emerges when gamma is nested within larger temporal frameworks.
Catherine Tallon-Baudry:
From the human perspective, gamma correlates beautifully with the feeling of seeing something. In visual tasks, perception without awareness shows weaker or absent gamma. So, gamma reflects the subjective access to information. Whether it causes it or not, it is the rhythm most aligned with the conscious spark.
Ole Jensen:
Let me push this further: consciousness may not reside in any single frequency. Gamma is one gear in a clockwork. It entrains with theta and alpha rhythms, forming cross-frequency couplings. Consciousness might emerge from these nested structures, not from 40 Hz in isolation.
David Chalmers:
That’s illuminating — some of you see gamma as a spark, others as scaffolding, still others as one gear among many. Let’s move deeper: could we actually use 40 Hz stimulation to restore or enhance consciousness in patients with disorders of consciousness?
Question 2: Can we use 40 Hz stimulation to restore consciousness?
Li-Huei Tsai:
We’ve begun pilot studies where 40 Hz light and sound stimulation is applied to patients with mild cognitive impairment. The results are modest but hopeful — improved connectivity, reduced brain atrophy. For coma or vegetative states, it is speculative, but if gamma truly facilitates network communication, entrainment could offer a doorway back to awareness.
Catherine Tallon-Baudry:
I would add: in EEG studies of patients in minimally conscious states, gamma activity is severely diminished. So, stimulating at 40 Hz might at least reinstate the brain’s capacity for large-scale integration. But one must be cautious not to equate induced rhythms with subjective recovery. We may make the brain look alive without restoring the inner life.
György Buzsáki:
This is precisely the problem. You can force neurons to dance, but is it music? If you drive 40 Hz artificially, you might produce synchronization without meaning. Consciousness is not just neurons firing together; it is content-rich. Stimulation could help, but I doubt it will recreate awareness on its own.
Ole Jensen:
Yet, if stimulation can help synchronize large networks, it could increase the probability of conscious moments. Think of it as tuning an orchestra before the performance. You can’t guarantee the music will be sublime, but you can ensure the instruments are in harmony.
Christopher Moore:
I think of it like CPR for the mind. Gamma stimulation might not produce full consciousness, but it could sustain the conditions under which fragments of awareness can re-emerge. Combined with behavioral therapy or pharmacological agents, it could become part of a toolkit for reviving awareness.
David Chalmers:
A powerful metaphor — CPR for the mind. Now, for the final thread: what does gamma tell us about the unity of conscious experience? Why do we feel a single, seamless stream instead of scattered bits of perception?
Question 3: Does gamma explain the unity of consciousness?
Christopher Moore:
Yes, to a degree. Gamma bursts occur across sensory areas simultaneously, binding sight, sound, and touch into a coherent frame. It may not explain why this feels unified, but it gives a mechanistic account of how the brain prevents fragmentation.
György Buzsáki:
But beware: unity is an illusion of scale. At the neuronal level, there is no unity, only distributed patterns. Gamma provides temporal tags that help coordinate, but the subjective sense of unity is something philosophers like you, David, must wrestle with. Neuroscience cannot fully account for qualia.
Catherine Tallon-Baudry:
Still, we should not underestimate gamma’s power. It aligns subjective reports with measurable brain activity. When people say, “I see it now,” their gamma activity reflects that transition. The rhythm is not the essence of consciousness, but it is the tempo at which the orchestra of awareness plays.
Li-Huei Tsai:
And if gamma provides this tempo, then enhancing or repairing it may help restore that fragile unity in diseased brains. We may never fully explain why it feels like one stream, but clinically, preserving the rhythm could preserve the sense of self.
Ole Jensen:
I’ll close with this: gamma is not the answer to unity, but the bridge. It connects local computations into global assemblies. The feeling of seamless consciousness may be an emergent phenomenon of nested rhythms, with gamma as the fast beat weaving the threads together.
David Chalmers (Moderator):
What a fascinating spectrum of views. For some of you, gamma is a vital tempo; for others, it is scaffolding or a bridge. What unites you all is the recognition that 40 Hz plays a privileged role in the brain’s language of coordination. Whether this language is sufficient to explain why the lights are on remains the enduring mystery. But if we can tune the rhythms of the brain, perhaps we are one step closer to tuning into the nature of consciousness itself.
Topic 2: Healing the Brain — Can 40 Hz Stimulation Reverse Neurodegeneration?
Rudolph Tanzi (Moderator):
Neurodegenerative diseases like Alzheimer’s have long resisted effective treatments. Yet 40 Hz stimulation has sparked optimism, showing reductions in amyloid plaques in mice and early benefits in humans. To begin, let’s ask the fundamental question: how strong is the evidence that 40 Hz stimulation truly heals the brain, rather than just providing temporary effects?
Question 1: Does 40 Hz stimulation truly heal the brain or just mask symptoms?
Li-Huei Tsai:
In our mouse studies, daily exposure to 40 Hz light and sound reduced both amyloid plaques and tau tangles, while also activating microglia to clear debris. These are not just symptomatic changes but structural shifts in pathology. In early human trials, we see preserved white matter volume and slowed hippocampal atrophy. It’s not a cure, but it is more than surface-level.
György Buzsáki:
I admire these results, but I must raise caution. Pathology reduction does not equate to restored cognition. The brain is not like a clogged sink you can simply clear out. Networks once disrupted may not reconnect properly, even if plaques are gone. Healing requires the restoration of functional dynamics, not only cellular cleanup.
Edward Boyden:
That is why engineering matters. By pairing stimulation with precisely timed patterns, we may guide networks back into coherence. Optogenetic experiments already show us that driving gamma can re-establish lost rhythms. The key is not just frequency, but control over timing, duration, and brain region targeting.
Christopher Moore:
I’d argue the biggest promise lies in neuroplasticity. Gamma rhythms are associated with synaptic strengthening. If we can maintain that environment, the brain has a chance to rewire itself around damaged areas. Healing may not mean reversing pathology, but enabling the brain to adapt and function despite it.
Ole Jensen:
Yes, and we mustn’t underestimate the role of large-scale connectivity. MEG studies show that in Alzheimer’s, gamma synchrony across distant regions collapses. If 40 Hz stimulation restores synchrony, it could re-establish the scaffolding for plasticity. Whether that translates to long-term cognitive gains, however, remains to be seen.
Rudolph Tanzi:
That brings us to the next issue: if the effects are real, how might this scale beyond Alzheimer’s? Could 40 Hz stimulation apply to other brain disorders like Parkinson’s, depression, or trauma?
Question 2: Can 40 Hz stimulation help conditions beyond Alzheimer’s?
Edward Boyden:
Absolutely. Gamma rhythms are fundamental to information processing, not unique to Alzheimer’s. In Parkinson’s, abnormal beta oscillations dominate, and introducing gamma could counteract them. In depression, disrupted network coherence may benefit from rhythmic entrainment. The principle is general: by restoring the brain’s “timing,” we open doors across conditions.
Li-Huei Tsai:
We are cautious but hopeful. In animal models, 40 Hz stimulation enhances vascular flow and reduces neuroinflammation — processes relevant to many disorders. For traumatic brain injury, for example, restoring blood flow and reducing inflammation may provide significant benefit. Each condition, however, may require tailored protocols.
György Buzsáki:
But again, beware of overselling. Each disease has unique pathophysiology. What helps in amyloid pathology may not touch dopamine neuron death in Parkinson’s. Gamma is not a panacea. It is one tool among many, and its effectiveness must be validated case by case.
Ole Jensen:
Still, consider the versatility: gamma interacts with multiple neurotransmitter systems. By modulating GABAergic interneurons, we influence balance across excitatory and inhibitory networks. This modulation could benefit a wide range of dysfunctions, though the effects will differ. Think of gamma not as a drug but as a tuning fork that can align different instruments of the brain.
Christopher Moore:
I’d add that even if gamma stimulation does not cure these diseases, it could improve quality of life. Enhancing attention, perception, or memory function by just 10–15% could transform daily living for patients with dementia, depression, or PTSD. Sometimes “healing” is about function, not elimination of pathology.
Rudolph Tanzi:
Important points — healing doesn’t always mean cure, but restoration of meaningful function. Let’s end with the broader horizon: what are the risks and ethical challenges of pursuing gamma stimulation as a therapy?
Question 3: What are the risks and ethical challenges of gamma stimulation therapy?
Ole Jensen:
From a methodological view, the biggest risk is over-interpretation. EEG and MEG can show increased gamma activity, but that does not guarantee improved cognition. If companies commercialize devices prematurely, we risk creating hype without substance, damaging trust in neuroscience.
Li-Huei Tsai:
Clinically, safety is paramount. Light and sound stimulation appear safe, but we must watch for unintended consequences — overstimulation, sleep disruption, or even kindling epileptic activity. Careful trials are necessary before broad application.
Edward Boyden:
Ethically, we must also ask: who controls access? If gamma devices become consumer wearables, will people use them responsibly? Or will companies market “super-brain enhancers” without clinical oversight? Regulation must ensure therapeutic use without exploitation.
György Buzsáki:
And philosophically, we must ask: what are we doing when we engineer rhythms into the brain? Are we restoring natural states, or imposing artificial ones? If we treat the brain like a machine, we may forget that consciousness and identity are not merely oscillations to be tuned.
Christopher Moore:
Still, I would argue the risk of inaction is greater. With millions suffering from neurodegeneration, not exploring 40 Hz would be irresponsible. The challenge is to proceed with both rigor and humility — to test boldly but interpret carefully.
Rudolph Tanzi (Moderator):
Thank you all. We have heard optimism, caution, and ethical vigilance. Gamma stimulation may not be a magic bullet, but it is a promising tool — one that could slow decline, restore coherence, and improve lives. Whether it heals fully or only partially, its true value will lie in how we integrate it with other therapies and safeguard its use.
Topic 3: Technology and Ethics — The Future of Brain Entrainment
Yuval Noah Harari (Moderator):
We’ve seen brain technologies evolve from crude stimulation to targeted neuromodulation. Now, with 40 Hz gamma entrainment devices, we may stand at the edge of influencing not just disease, but mood, cognition, and even identity. Let’s start with the core question: what are the real risks of widespread brain entrainment technology?
Question 1: What are the risks of widespread brain entrainment?
Edward Boyden:
The first risk is misuse. Technology designed for therapy could easily become marketed as “neuro-enhancement.” Imagine wearable devices promising to boost memory or creativity, but without clinical evidence. The brain is delicate — you can’t just dial up gamma without unintended consequences. Engineering requires precision, and society often rushes past caution.
Catherine Tallon-Baudry:
Another risk is illusion. Increased gamma on an EEG may look impressive, but it doesn’t guarantee improved subjective experience. Companies may sell rhythms as if they are the same as “awareness” or “focus.” We risk equating numbers with human meaning. The ethical danger lies in oversimplification.
Li-Huei Tsai:
Clinically, I worry about premature application. In Alzheimer’s trials, we carefully monitor safety and efficacy. But once devices are cheap, they may be adopted without oversight. Overstimulation could disrupt sleep cycles or cause stress responses. Risks may be subtle — not seizures or injuries, but gradual dysregulation of natural rhythms.
Christopher Moore:
There is also the danger of inequity. If such devices truly improve cognition, access will matter. Will only wealthy families be able to “tune” their children’s brains for academic advantage? Neuroscience could inadvertently widen social divides under the banner of “wellness.”
Ole Jensen:
And from a scientific perspective: the risk of stagnation. If society believes brain entrainment is a solved path, funding may dry up for deeper research. We must not allow consumer hype to replace rigorous investigation into how rhythms truly work.
Yuval Noah Harari:
Strong warnings. Let’s shift to the opposite side: what are the potential benefits if we deploy this technology wisely? Could entrainment become part of daily health?
Question 2: What are the benefits of gamma entrainment if used wisely?
Li-Huei Tsai:
If used correctly, it could become as common as exercise. Just as we now accept that daily physical activity prevents disease, regular 40 Hz stimulation could preserve brain health. Imagine clinics prescribing “neural fitness sessions” to reduce dementia risk — preventative care through rhythm.
Edward Boyden:
Yes, and we can personalize it. Not everyone’s brain responds to the same stimulation. With adaptive devices that measure EEG in real time, we could deliver precisely timed patterns to strengthen an individual’s networks. This is medicine tuned to the rhythm of the patient, not one-size-fits-all.
Catherine Tallon-Baudry:
I see potential in mental well-being. Many psychiatric conditions involve disrupted oscillations. Gentle entrainment could complement therapy, helping people regulate attention, mood, or anxiety. Unlike drugs, which flood the whole brain, rhythms target coordination. It’s a subtler lever.
Christopher Moore:
For education, too. If we understand how gamma supports attention and perception, we could design classrooms that naturally entrain healthy rhythms — through lighting, soundscapes, or even interactive tools. The benefit is not just clinical, but cultural.
Ole Jensen:
And for science itself. By experimenting with real-time entrainment in humans, we gain a tool to test theories of consciousness and cognition. Benefits go beyond therapy — they deepen our fundamental knowledge of the brain’s timing code.
Yuval Noah Harari:
Fascinating — entrainment as medicine, education, even culture. But every tool carries the shadow of control. My final question: who should govern the future of brain entrainment — scientists, governments, companies, or individuals?
Question 3: Who should control the future of brain entrainment?
Christopher Moore:
It must be science-led. Regulation without research becomes guesswork. We need open, transparent trials, peer review, and long-term data before policy is made. Scientists must guide the guardrails, not corporations.
Li-Huei Tsai:
I agree, but scientists alone cannot govern. Collaboration between academia, government, and industry is necessary. We must build a framework similar to how we regulate pharmaceuticals: safety trials, clear labeling, and restricted claims.
Edward Boyden:
But let’s also empower individuals. Neurotechnology should not become paternalistic. Patients deserve the right to experiment with their own brains, provided safety standards are met. A balance is needed — regulation for safety, freedom for personal exploration.
Catherine Tallon-Baudry:
Yet, freedom has limits. Imagine employers requiring workers to undergo daily gamma sessions to “optimize productivity.” Or authoritarian states using entrainment as subtle coercion. Governance must protect against misuse not only in commerce, but in politics.
Ole Jensen:
Therefore, international collaboration is key. Just as we have treaties for nuclear and genetic technologies, brain technologies need oversight beyond national borders. Rhythms do not respect boundaries; neither should ethics.
Yuval Noah Harari (Moderator):
Thank you. What emerges here is a tension between promise and peril. Brain entrainment could become medicine, education, even everyday health — yet it could also become a tool for inequality or control. Like fire or writing, it is a technology that reshapes what it means to be human. Whether it liberates or enslaves depends not on the rhythm itself, but on how wisely we choose to conduct the orchestra of society.
Topic 4: Cross-Frequency Conversations — Gamma’s Relationship with Theta, Alpha, and Beyond
Anil Seth (Moderator):
The brain does not operate in isolation by frequency; rhythms intertwine. Theta, alpha, beta, gamma — together they shape perception and thought. Let me begin with this: is gamma truly distinct, or must we always study it in relation to other brain rhythms?
Question 1: Is gamma truly distinct or only meaningful in relation to other rhythms?
György Buzsáki:
Gamma never acts alone. In the hippocampus, gamma is nested within theta cycles — the slower rhythm providing a temporal scaffold for the faster one. It is this nesting that allows information to be chunked and ordered. So to isolate gamma from theta, or alpha, is to miss the architecture of cognition. Gamma is distinct, yes, but only as a member of the ensemble.
Edward Boyden:
From a technology perspective, the interplay is critical. When we entrain at 40 Hz, we should ask: how does that lock to slower rhythms? Can we tune the brain like a multi-band radio, synchronizing across channels? Devices of the future won’t just drive gamma, but orchestrate cross-frequency harmonics.
Catherine Tallon-Baudry:
In human perception, gamma gains meaning through its relationship to alpha. For example, alpha rhythms seem to gate what enters awareness — an inhibitory filter. Gamma represents the active content. Without alpha, gamma would be chaotic; without gamma, alpha would be silent. Together they create the rhythm of attention.
Christopher Moore:
I’d add that gamma by itself is too fleeting. Bursts of gamma last mere hundreds of milliseconds. Only by coupling with slower rhythms do they scale into meaningful perception and cognition. Gamma is a spark; the slower rhythms are the canvas.
Ole Jensen:
Indeed, MEG studies consistently show phase-amplitude coupling between alpha/theta phases and gamma power. This suggests hierarchy: slower rhythms set the frame, gamma fills it with details. To study gamma without its partners is like studying speech without syntax.
Anil Seth:
Beautiful analogies — spark and canvas, speech and syntax. Let’s move deeper: how do these cross-frequency couplings influence memory, attention, and creativity?
Question 2: How do cross-frequency rhythms shape cognition?
Catherine Tallon-Baudry:
In vision, gamma synchrony encodes the “what,” while alpha determines the “when.” When alpha gates open, gamma synchrony allows features to bind into percepts. This temporal dance underlies the subjective moment of seeing.
György Buzsáki:
For memory, theta-gamma coupling is the backbone. Each theta cycle is like a sentence; within it, gamma bursts encode the words. This explains how sequences of experiences are ordered in the hippocampus. Without this coding scheme, memory fragments into noise.
Edward Boyden:
Creativity may be the frontier. If gamma encodes details, and slower rhythms set the frame, then creative insight might arise when unusual couplings occur — new timing relationships that link distant concepts. Engineering devices that promote cross-frequency flexibility could enhance creative cognition.
Christopher Moore:
And for attention, it’s about balance. Too much alpha suppression, and gamma floods in uncontrollably, leading to distractibility. Too much alpha dominance, and gamma is muted, leading to sluggishness. Attention is the art of rhythm balance, not raw gamma power.
Ole Jensen:
Exactly. Our MEG data show that in working memory tasks, the strength of cross-frequency coupling predicts performance. It is not gamma alone, but its alignment with theta and alpha phases that determines success. Cognition is not one rhythm, but a polyrhythm.
Anil Seth:
So cognition itself is polyrhythmic. My final question is a bit more speculative: if we could consciously control or modulate these rhythms — theta, alpha, gamma — what would that mean for our sense of self?
Question 3: What would conscious control of rhythms mean for the self?
Christopher Moore:
It would mean agency over perception itself. Imagine being able to open and close the alpha gates at will — choosing what enters awareness. Or amplifying gamma to bind thoughts more vividly. The self would become a conductor, not just a listener, of mental rhythms.
Edward Boyden:
Technologically, this is plausible. Brain-computer interfaces could provide feedback, allowing users to train their rhythms. The ethical question is: do we remain ourselves if our rhythms are engineered? Or do we become hybrid selves — human-machine oscillators?
György Buzsáki:
I would remind us: the self is already an emergent rhythm. What you call “I” is the temporal binding of countless neural events. To consciously control rhythms would not change the self — it would simply reveal its musical nature. The self is already the conductor and the symphony.
Catherine Tallon-Baudry:
But subjectively, it could change our relation to experience. If rhythms give rise to the flow of consciousness, learning to modulate them might allow new states of awareness — expanded presence, altered time perception. The self would not be lost, but enriched.
Ole Jensen:
Still, we must remain humble. The brain’s rhythms evolved for reasons. If we tamper too much, we risk destabilizing the delicate balance that sustains coherence. Conscious control may be liberating, but it could also fragment the very unity we seek to enhance.
Anil Seth (Moderator):
What a profound exchange. Gamma is not an isolated note but part of a polyrhythmic symphony. It couples with theta and alpha to bind perception, memory, and creativity. If we could one day guide these rhythms ourselves, we might alter not just brain states, but the very texture of selfhood. Yet, as you all remind us, the music of the mind is delicate — to play with it requires both wonder and caution.
Topic 5: The Philosophy of Rhythm — What Does Gamma Tell Us About Being Human?
Evan Thompson (Moderator):
We’ve spoken of gamma as coordination, therapy, and technology. But today I want to ask: beyond the laboratory, beyond devices, what does gamma tell us about being human? Let’s begin here: are brain rhythms like 40 Hz just biology, or do they reveal something about our deeper nature?
Question 1: Are rhythms just biology, or do they reveal something deeper about being human?
György Buzsáki:
Rhythms are biology, but biology is profound. Every cell oscillates — the heart, the lungs, the circadian cycle. Gamma is simply the brain’s version of this universal rhythm. To me, it reveals that humans are rhythmic creatures. We think in patterns because life itself is patterned. Calling it “just biology” misses the poetry of biology.
Li-Huei Tsai:
I agree, and I’d add: gamma rhythms reflect resilience. In Alzheimer’s, when rhythms break down, so too does the sense of self. The restoration of 40 Hz isn’t only about cognition; it is about re-establishing continuity of identity. Rhythm is the thread that keeps the person whole.
Edward Boyden:
From an engineering view, rhythms are code. Gamma is a computational strategy — a way the brain manages massive amounts of information efficiently. Yet seeing this makes me feel awe. That such simple mathematics underlies human thought suggests that we are, at root, both matter and meaning encoded in time.
Catherine Tallon-Baudry:
And subjectively, rhythms shape experience. When gamma aligns, perception feels clear, unified. When it falters, awareness fragments. Gamma shows us that being human is not static, but dynamic — a flow of coherence that can strengthen or waver. To me, it highlights our fragility and our beauty.
Ole Jensen:
Yes, and if we zoom out: gamma is one layer in a nested hierarchy, from slow waves to fast bursts. Humanity, too, exists in layers — individual moments nested in lifetimes, lifetimes nested in cultures. Studying gamma reminds us that our being is rhythmic not only in the brain, but in society and time itself.
Evan Thompson:
A beautiful opening — rhythms as poetry, code, fragility, and culture. Let’s go further: does gamma, with its role in unity of perception, teach us something about the unity of self? Why do we feel whole, despite our many parts?
Question 2: What does gamma reveal about the unity of the self?
Li-Huei Tsai:
When gamma is strong, information across brain regions becomes synchronized. In patients with dementia, gamma coherence collapses, and with it, the continuity of self. This suggests that our unity is not metaphysical but biological — a rhythm tying fragments together. To sustain gamma is to sustain the experience of “I.”
Catherine Tallon-Baudry:
But notice: gamma doesn’t explain the feeling of unity, only its mechanism. The subjective sense that “all of this is mine” remains a mystery. Still, gamma shows us how fragile unity is — it can flicker. Perhaps the self is not a solid entity but a rhythm sustained across time.
György Buzsáki:
I would push back slightly. The self is an illusion generated by rhythm. At the neuronal scale, there is only activity — no “self.” Gamma provides temporal tags that give coherence, and coherence creates the story of “me.” In that sense, gamma doesn’t reveal unity; it fabricates it.
Edward Boyden:
That may be, but even illusions can heal. If by restoring gamma we restore the illusion of unity, we restore dignity. Perhaps the self is not something we discover, but something we maintain — a rhythm we must continuously play.
Ole Jensen:
And that rhythm is never solitary. Gamma synchronizes not only within one brain, but between brains in interaction. When people converse, their rhythms entrain. The unity of self may thus be intersubjective — woven not only by neurons, but by shared timing between humans.
Evan Thompson:
Profound — the self as rhythm, illusion, and intersubjective dance. For our final question: if rhythms are so fundamental, what ethical or spiritual lessons should humanity take from the discovery of gamma’s role in life and mind?
Question 3: What ethical or spiritual lessons should we draw from gamma?
Edward Boyden:
For me, the lesson is humility. If our deepest thoughts and memories depend on rhythms, then we are more fragile than we imagine. This should inspire compassion — to treat each other gently, knowing how easily the rhythm can falter.
Li-Huei Tsai:
And responsibility. If technology can preserve or restore these rhythms, we have an obligation to use it wisely. Not just for profit, but for dignity, for memory, for love. Gamma entrainment is not just science; it is care.
Catherine Tallon-Baudry:
Spiritually, gamma teaches impermanence. The self arises and dissolves in rhythmic bursts. This aligns with many contemplative traditions — that consciousness is a flow, not a fixed thing. To see this scientifically is to bridge East and West, lab and meditation cushion.
Ole Jensen:
Ethically, I’d say the lesson is balance. Just as gamma must align with theta and alpha, so must our pursuit of technology align with nature and humanity. If we chase control without harmony, we will disrupt the very rhythms we seek to heal.
György Buzsáki:
I’ll close with this: gamma shows us that being human is not about static essence, but about dynamic coordination. To live well is to keep rhythm — within our neurons, within our communities, within the planet. Lose the rhythm, and life fragments. Keep it, and life sings.
Evan Thompson (Moderator):
Thank you. What I hear is not only science but philosophy: gamma as code, rhythm, illusion, compassion, impermanence, balance. Perhaps what it tells us most of all is that to be human is to be rhythmic — bound by patterns, yet capable of transcending them into meaning. In studying 40 Hz, we study not only the brain, but the fragile and beautiful rhythm of being alive.
Final Thoughts By Evan Thompson
Listening to this conversation, I am struck by how science and philosophy meet in rhythm. On the one hand, we have seen how 40 Hz gamma oscillations play a concrete role in cognition and healing — coordinating neurons, reducing pathology, sustaining memory. On the other hand, we have heard how fragile and elusive consciousness remains, never fully captured by data or stimulation.
What does this tell us about being human? To me, it suggests that we are rhythmic beings at every level. Our hearts beat, our lungs breathe, our brains oscillate. The flow of consciousness is not a solid block but a pulse, a dance of synchrony and desynchrony. Gamma rhythms remind us that selfhood itself is not a fixed entity but a process, arising and dissolving with each coordinated moment.
There is an ethical lesson here as well. If we can influence rhythms with technology, we must do so with care. To tamper with rhythms is to tamper with the very basis of self. This calls not only for scientific rigor but for compassion and responsibility. These are not just brain waves; they are the fragile ground on which memory, identity, and dignity rest.
And there is a spiritual lesson. Many contemplative traditions describe consciousness as a flow, a stream, a rhythm of arising and passing away. Gamma gives us a glimpse of this truth from within the brain itself. Science and philosophy converge on the same insight: to live is to be rhythmic, to be dynamic, to be ever-changing.
In the end, studying 40 Hz gamma is not only about curing disease or mapping cognition. It is about deepening our sense of what it means to be human — fragile, rhythmic, interconnected, and alive. If Buzsáki gives us the rhythm, and Tsai, Boyden, and others show us its healing power, then our task, as a human community, is to ensure that this rhythm is nurtured, protected, and honored.
Gamma is not just in the lab. It is in us, in the very music of being.
Short Bios:
Li-Huei Tsai
A neuroscientist at MIT and director of the Picower Institute for Learning and Memory, Tsai is best known for her groundbreaking work on 40 Hz sensory stimulation (GENUS). Her research demonstrates how gamma wave entrainment can reduce Alzheimer’s pathology and improve brain health, leading to clinical applications through Cognito Therapeutics.
Edward Boyden
A professor at MIT and co-founder of Cognito Therapeutics, Boyden is a pioneer in neurotechnology. He helped develop optogenetics and advanced tools for controlling and imaging brain activity. His work explores how technologies like light and sound stimulation at 40 Hz can restore cognitive function and rewire neural circuits.
György Buzsáki
Professor of Neuroscience at NYU School of Medicine, Buzsáki is a world authority on brain oscillations and network dynamics. His influential work has mapped the role of gamma, theta, and sharp-wave ripples in memory, perception, and cognition, establishing rhythms as the “syntax” of neural communication.
Catherine Tallon-Baudry
A French neuroscientist at the École Normale Supérieure in Paris, Tallon-Baudry is recognized for her research on gamma-band oscillations in human perception and consciousness. Using EEG and MEG, she explores how gamma activity correlates with subjective awareness, binding perception into unified experiences.
Christopher I. Moore
Professor of Neuroscience at Brown University, Moore investigates how brain rhythms govern sensory perception and cognition. His work focuses on the dynamic role of gamma oscillations in awareness and neural plasticity, often bridging laboratory research with translational applications.
Ole Jensen
A neuroscientist at the University of Birmingham and formerly at Oxford, Jensen specializes in magnetoencephalography (MEG) studies of brain rhythms. His research highlights cross-frequency coupling between alpha, theta, and gamma waves, revealing how nested rhythms support memory, attention, and large-scale brain coordination.
David Chalmers
A philosopher of mind at New York University, Chalmers is renowned for formulating the “hard problem of consciousness” — why subjective experience arises from physical processes. His work bridges philosophy, cognitive science, and neuroscience, making him a leading figure in consciousness studies.
Rudolph Tanzi
Professor of Neurology at Harvard Medical School and co-director of the McCance Center for Brain Health at Massachusetts General Hospital, Tanzi is a world leader in Alzheimer’s research. He co-discovered several key Alzheimer’s genes and advocates innovative approaches to prevention and treatment.
Yuval Noah Harari
A historian and professor at the Hebrew University of Jerusalem, Harari is the author of international bestsellers Sapiens, Homo Deus, and 21 Lessons for the 21st Century. His work explores the intersection of history, technology, and human meaning, with a strong emphasis on ethical implications of emerging sciences.
Anil Seth
Professor of Cognitive and Computational Neuroscience at the University of Sussex, Seth is a leading researcher on perception and consciousness. His work on predictive processing and brain rhythms has advanced the understanding of how neural activity creates the experience of reality. He is also the author of Being You.
Evan Thompson
A philosopher at the University of British Columbia, Thompson integrates neuroscience, phenomenology, and Buddhist philosophy. He is the author of Waking, Dreaming, Being and co-author of The Embodied Mind. His research focuses on the nature of consciousness, the self, and the interplay between science and lived experience.
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