Hijacking your post with a dubious segue because I’m itching to bounce these thoughts off somebody:
I’ve been consuming a lot of talks / writing recently about “enactive” pictures of how our brains function. From what I gather, recent studies have called into question the entire idea of real world concepts being “represented” by an area of the brain at all. While it’s true that atandard fMRI-style snapshots of brain activity are semi-stable over the course of a short experiment, it’s not true over longer timeframes. The response to the same stimulus will change over time. They refer to this as “representational drift” in the literature, and some people are using this to bolster theories of mind that they consider non-representational. They instead emphasize the brain as a kind of dynamical system that learns to “resonate” with the world to pull itself back into homeostasis. The focus shifts away from facts and memories as data, and sees neuronal plasticity more as a mechanism for tuning the brain’s resonant frequencies. This obviously places high importance on the spiking, recurrent nature of actual neurons, as opposed to the neurons-as-functions / back-propagation / ML approach.
My mind’s not made up on how interesting and revolutionary this approach is / isn’t. The distinction seems to be about whether learning is more like “writing to disk” or “tuning a PID controller” - but in either case, the world is leaving a stateful imprint on your brain that will impact how it processes future data. Is that important to understanding how brains work, or is it just semantics?
Some years ago, I heard a retired Lutheran priest ponder, in radio, about the concept of a prayer, and whether, as an edge case, an unborn child could be able to pray, with the child of that age having no understanding on the required concepts. This is apparently one of those questions that people ponder under the umbrella of philosophy of religion. His conclusion was that prayer was about harmonizing one's self with the universe. It's a beautiful thought, (and I think religions, of all kinds, are really good at providing the fertile ground for thoughts like these).
It's akin to how the saying goes, that when we argue, we need to reach the same wavelength where the other one is to reach an understanding.
In communication studies or sociology or linguistics or one of those fields, there's the idea that communication is about making pacts about meanings, and finding the common ground to understand and delimit the message.
In a sense, from that basing, one could argue that understanding can be seen as an act of harmonizing. I think there's something universal in it.
Ooh thanks for the hijack! It’s so much easier to talk to someone who isn’t stuck in a picture of the brain from the 1980s.
Yes, I fall more towards the camp that a lot of our cognitive models, built from times when we didn’t have the resolution of understanding we have of the capacity of even a single neuron, and before we knew how astrocytes played a role, suffer from being an abstraction describing an abstraction. They are not tethered in the dynamics of the molecules and cells that give rise to the behavior, but rather from an interpretation of observed behavior.
This paper from the field of chronobiogy is one I’d recommend that helpfully contrasts this:
https://www.sciencedirect.com/science/article/abs/pii/S00393...
>In circadian research, the models are not proposals regarding the basic architecture of circadian mechanisms; rather, they are used to better understand the functioning of a mechanism whose parts, operations, and organization already have been independently determined. In particular, circadian modelers probe how the mechanism’s organized parts and operations are orchestrated in real time to produce dynamic phenomena—what we have called dynamic mechanistic explanation.
And what you’re describing, the enactivist description of cognition, (and 4E cognition more broadly as a framework), is one way the neuroscience community is trying to move past these issues.
Few things that give me confidence these are the right track:
1. Circadian rhythms are evolutionarily ancient. Bacteria have em. Plants have em. But different molecular tools shape very different clocks, though the same 24 hour cycle is being tracked. 2. The way these rhythms are generated is not through some central system that broadcasts the information to other regions. Instead, it’s instantiated in every cell in the body, and the behavioral rhythm is due to the synchrony between cells. Resonance absolutely plays a role, and has been well documented. The brains role, via the suprachiasmatic nucleus or SCN, is to orchestrate this synchrony, but it is not the source of the rhythms. 3. This slow rhythm definitely regulates cognition (time of day effects in learning, memory formation, recall etc are well documented), but turns out, the molecular mechanisms by which the clock responds to light hugely overlap with the molecular mechanisms of learning in the synapse, and even more recent work has shown clock proteins are actually in the synapses and synaptic activity affects the clock.
All this points to nested oscillators with cross frequency coupling, and even better, because this is all grounded in actual molecular dynamics, there’s plenty of falsifiability. The phase amplitude links are best established for the faster rhythms, the famous “brain waves”. Highly recommend György Buzsáki‘s work on this:
https://www.jneurosci.org/content/32/2/423.short
What’s missing is going down into lower frequency rhythms, and testing how exactly they all couple. We have a lot of the pieces, but no single experimental paradigm that has looked at the full sweep over different times in the same organism. It’s not easy to do, but we’ll get there.
Clock disruption, depending on how you do it, has huge impacts on time perception, cognition, memory, aging AND consciousness. As that data and evidence gets more and more saturated, I hope we see more studies account for chronotype and the internal dynamical state of their test subjects when assessing outcomes.
Obviously I’m biased (also did chronobiology in school), but hopefully I’ve left you curious. Happy to answer more questions all this may have set off.
Thanks for your response, very intriguing! I have some controls background, and there’s something tantalizing about the idea that perhaps we need to be looking at the brain in frequency space, as it were. Are you aware of reservoir computing and do you see it playing a part in this?
Yes I’ve come across reservoir computing. As a neuroscientist, it made me sit up and take notice.
I’d say that I feel there’s homology in language. What reservoir computing says about the efficiency benefits of having a fixed but tunable dynamics to use as an underlying reservoir feels very adjacent to how I intuitively think of brain function.
The key thing from the circadian field you’ll appreciate:
The biological clock is a limit cycle oscillator. You have a bunch of chemical reactions that have negative feedback and some feedforward arms, and together they create a dynamical 24-regime. About 40-60% of the transcriptome of any given cell shows circadian dynamics.
Now this gives you phase, and an internal temporal reference for all your functions. In chronobiology, you call this the organisms subjective time. The system is chemically partitioned not just physically but over time, and behavior results from the dynamical interactions underneath which are concerned with anticipating solar and lunar periodicities in the environment, since those are so very common and determinative to fitness in many niches.
Note the fact that it is subjective time but has an objective description. However, external measurement without the background of the chronotype accounted for will thing of a lot of variance as “noise”.
My own philosophical conclusion has been that this is the source of our confusion with consciousness. We don’t account for the internal causal order of events, which are timed, and with cross frequency coupling and phase-amplitude linkages begging to be worked out with real world data.