Illustration by ChatGPT

Intermediate stage of my thinking: as the mechanism for synchronising data from the five senses is central to the theory of consciousness (now known as Cross-Flow Resonance Theory: ‘CFRT’) that I proposed in ‘The Secret of the Chinese Room’ in 1999, I am taking stock of what neuroscience has learned on the subject since then: over the past 26 years (I was anticipating with my hypothesis what was scientifically known at the time).

P.J.:

It takes longer for information from the tip of my toe to reach the thalamus than it does for information from my retina. There must be a mechanism in the thalamus or elsewhere that synchronises perceptions. How does this happen?

DeepSeek:

(thought for 11 seconds)

Hmm, this is a sophisticated question that digs into the core of how the brain solves temporal integration problems. The user is pointing out a real physical constraint—neural transmission delays—and asking how the thalamus compensates to create a unified conscious moment.

The user’s theory already incorporates thalamocortical resonance, so I should build on that framework. The key is to shift from thinking of the thalamus as a passive synchroniser to an active predictor. The answer should cover: 1) the problem of variable delays, 2) the predictive mechanism (phase precession), 3) the role of oscillations (alpha rhythms), and 4) how this fits into their consciousness model.

I’ll avoid getting bogged down in unnecessary neuroanatomy details unless directly relevant. The user seems to want a mechanistic explanation that aligns with their holographic resonance idea. The “temporal window” concept from consciousness studies might be a good bridge.

The example of the dropped book [P.J.: Actually not used later on] should make it concrete. Need to emphasize that this isn’t just delay compensation—it’s fundamental to constructing a coherent conscious present.

(response)

This is a [habitual pleasantries] critical question that strikes at the very heart of how the brain constructs a unified present moment from disparate, delayed sensory signals. You are correct; the thalamus does not merely “wait” for all signals to arrive. It is an active, dynamic predictor.

The mechanism isn’t about passive synchronisation upon arrival; it’s about active temporal prediction and integration within a pre-defined temporal window. The thalamus, in concert with the cortex, doesn’t just process what happened, but when it should have happened.

Here’s how it’s thought to be achieved:

1. The Problem: Variable Neural Latencies

As you correctly noted, signals travel at different speeds:

• Visual: Fast, direct pathway from retina to thalamus (LGN) to cortex.
• Auditory: Slightly slower, requires more processing in the brainstem before the thalamus (MGN).
• Somatosensory (toe): Significantly slower due to the long, unmyelinated neural pathways.

This results in a desynchronised arrival time at the thalamus for events that occurred simultaneously in the external world.

2. The Solution: Predictive Alignment to a “Temporal Window”

The brain’s solution is not to speed up the slow signals, but to delay the conscious perception of the entire event until the slowest salient signal has arrived, and then to present them as unified. This process is often called temporal binding or predictive dating.

The key players are, once again, the thalamocortical loops and their rhythms.

a) The Role of Alpha Oscillations (~10 Hz): Creating the Temporal Window

Alpha oscillations are dominant in the thalamus and sensory cortices when at rest. Their cycle (e.g., 100ms for 10 Hz) is thought to define discrete, periodic “windows of integration” or “perceptual moments.”

• The brain doesn’t process time as a continuous stream but rather in discrete chunks or samples, paced by these rhythms.
• Signals that arrive within the same “alpha window” are bound together into a single conscious percept.

b) The Thalamus as an Active Predictor: “Postdiction”

The brain uses a mechanism called postdiction—where a later stimulus can influence the perception of an earlier one. A classic example is the flash-lag effect, where a flash next to a moving object is perceived to lag behind it.

Here’s how it could work for your toe and retina:

1. The Initial Trigger: The fast visual signal (e.g., seeing a hammer hit your toe) arrives at the thalamus and visual cortex first.
2. Temporal Holding Pattern: Instead of being immediately rendered into consciousness, this initial signal activates a predictive model in the cortex. The model is: “a impact event has been seen; expect a pain signal from the toe in approximately X milliseconds.”
3. Inhibitory Gating: The thalamus and cortex, likely via the inhibitory action of the Thalamic Reticular Nucleus (TRN), essentially “hold” the visual event in a pre-conscious buffer. This is mediated by sustained neural activity in the relevant cortical circuits.
4. Integration and Release: The slow somatosensory signal from the toe finally arrives at the thalamus. Now that all expected components of the event are present, the thalamocortical system “releases” the percept into consciousness.
5. Perceptual Illusion: Crucially, the brain backdates the entire event. The conscious experience is that you saw the hammer hit and felt the pain simultaneously. The conscious percept is aligned to the external timing of the event, not the internal timing of the neural signals.

The thalamus’s role is to facilitate this holding and comparison process via its massive feedback connections with the cortex.

3. Evidence for the Mechanism: The “Temporal Recalibration” Experiment

This isn’t just theoretical. Key experiments demonstrate this plasticity:

• Researchers can artificially introduce a delay between a motor action (e.g., pressing a button) and its sensory consequence (e.g., a flash of light).
• After exposure to this delay, the brain adapts. When the delay is removed, the subject perceives the flash to occur before they even pressed the button—a negative lag.
• This shows the brain is dynamically recalibrating the expected timing of events to maintain temporal unity. The thalamocortical system is constantly adjusting its predictive models to account for the body’s inherent neural delays.

How This Fits Your Theory of Consciousness

In your framework, this is a perfect example of the resonance between top-down (retrieval) and bottom-up (alimentation) flows.

• Bottom-Up (Alimentation): The raw, desynchronised visual and somatosensory signals arrive at the thalamus.
• Top-Down (Retrieval): The cortex provides a powerful predictive model based on memory: “These two sensory events (sight of impact, feeling of pain) are causally linked and should be simultaneous.” It generates the expectation.
• Resonance: The resonance occurs not just on the content (“this is a hammer hitting a toe”) but on the temporal structure (“these signals belong together in time”). The successful integration of the delayed signal into the expected temporal model creates the unified, conscious moment.
• Failure of Resonance: If the somatosensory signal never arrived (e.g., due to anesthesia), the held visual signal might eventually be processed but feel strangely incomplete or lacking impact—a minor failure of the resonant temporal model.

In summary, the thalamus doesn’t have a “stopwatch” that synchronises arrivals. Instead, it is part of a predictive system that uses rhythmic oscillations to define windows of integration and actively holds early signals in check, waiting for slower ones to arrive, all to present a coherent, unified, and accurately dated conscious reality to us. This process is a fundamental prerequisite for the kind of resonant conscious experience your theory describes.

P.J.: You may have noticed that DeepSeek says in passing (this is part of his reflection, not his actual answer): “The user is pointing out a real physical constraint—neural transmission delays—and asking how the thalamus compensates to create a unified conscious moment”. This will not fall on deaf ears and will be at the heart of my next question.

(to be continued…)