A new paper in Cell measures theta waves in the hippocampus of rats navigating a maze with multiple spatial paths. They found a decision-making process seemed to be involved consistently with theta wave patterns. The paper itself requires a subscription or purchase but there is a good article on it in Quanta Magazine.
The hippocampus generated a representation of the left-turning choice during one cycle, then switched to the right-turning choice for the next one. The scenarios didn’t always alternate perfectly throughout the experiment — occasionally the same one would persist for a few cycles — but the structure in the signals was undeniable. The 125-millisecond sequences seemed to segregate the brain’s different hypotheses about the future into a continuous and consistent overall framework.
One could regard the brain waves themselves as incidental to the decision-making that is really being done by the brain circuits, but this association of brain waves with cognitive processes is what would be expected by EM field theories.
Apparently this is solid evidence in support of the notion that brains are not conscious in themselves, though they may produce consciousness by means of EM waves. I’d like to help these scientists by providing them with my corresponding psychology based “dual computers” model of brain function. It’s been difficult to help others understand it given how entrenched the idea is that phenomenal experience exists by means of generic information processing. Fortunately that’s not a problem for you. Perhaps tonight I’ll put together a psychology based account of what I suspect goes on in these rats.
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I would say suggestive evidence that still could be interpreted differently.
I actually can’t see it as solid or even suggestive evidence. Brain waves are ubiquitous in mainstream neuroscience, where as James noted in the post, they’re taken as indicators of activity, not causes, similar to the way fMRI uses blood oxygen levels as an indicator.
What I think EM field theories need, what any scientific theory needs, are one or more unique predictions, predictions that more established neuroscience theories would not make, predictions that turn out to be accurate, or at least more accurate than those other theories.
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I disagree. Yes brain waves are ubiquitous in mainstream neuroscience which is why it is unusual from my view that the EM fields generated by the electrical activity they measure are regarded as completely non-consequential.
What are the “unique predictions” of “brain circuits = consciousness” theory?
I wouldn’t say EM fields are necessarily seen as completely inconsequential. There’s a lot of stochastic variability in synaptic processing, and it’s possible electrical fields play some perturbational role, but there’s scant evidence that that role is functional.
On unique predictions, well, physical changes to the brain circuits should affect consciousness. Severing axons between key regions should damage it. Wide scale damage should extinguish it. All of which are borne out by many tragic case studies in neurology.
Of course, the brain has plasticity and can often recover by rerouting and repurposing other circuits, but its effects are often limited, particularly in a mature brain, and it doesn’t happen instantly.
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I would concede that your unique predictions are pretty well demonstrated.
I would also concede that brain circuits are necessary for consciousness.
But what do you have for predictions that would demonstrate that brain circuits are sufficient by themselves to produce consciousness.
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James, my response is the same that I give for people who ask for evidence of physicalism. The absence of something can’t be demonstrated. All we can do is observe the lack of evidence for it.
Okay. I was just trying to reconcile this with your statement: “What any scientific theory needs, are one or more unique predictions, predictions that more established neuroscience theories would not make, predictions that turn out to be accurate, or at least more accurate than those other theories.”
Apparently we don’t have any strong predictions or theory about how brain circuits create consciousness but just an absence of evidence about anything else being required.
Global workspace, higher order thought, integrated information, recurrent processing, and attention schema theories, among many others, all work with data from mainstream neuroscience. None of them necessarily rule out other stuff happening, but that’s any scientific theory. Natural selection doesn’t rule out other factors in evolution, nor cell theory that there can be life other than in cells, nor gene theory that nothing besides genes are involved in heritability.
Okay Mike, that article (and I presume the paper in Cell), does not provide “solid evidence in support of the notion that brains are not conscious in themselves, though they may produce consciousness by means of EM waves” as I said. Jordana Cepelewicz even spoke from the standard “brains are conscious” perspective rather than what I’d have said, or that they produce it.
But I also consider there to be no solid evidence that consciousness exists by means generic information processing. For example, what exists which produces no EM radiation (such as the proper symbols written extremely fast) but can also feel what I do when my thumb gets whacked? In fact I think a great case can be made that this generic information possibility would need to invoke supernatural dynamics. Adding EM fields associated with neuron firing (or some such mechanism), would naturalize an otherwise non-natural proposal.
As for finding evidence which supports EM theory in opposition to notions that consciousness exists by means of information processing alone, I suspect that evidence will be found that neuron firing in different parts of the brain interact at essentially light speed to produce phenomenal experience. Note that this removes an extreme speed limit associated with standard chemical-electrical neuron function. Here the conscious entity should exist not as brain, but as something that it produces, or those waves themselves. Furthermore note that the brain would need to monitor the desires of this sentient entity to algorithmically support this second kind of function. Here brain function gains a teleological dynamic, and so may be expected to deal better with more open circumstances which can’t otherwise be programmed for.
So apparently when these rats were less consciously sure which way to go, a more alternating 1/8th of a second wave signature was found. Under my own model even that would be classified as non-conscious function. But in these brain waves I suspect that a sentient entity may be said to exist which interprets conscious inputs, such memory, and constructs scenarios regarding its purpose to feel as good as it possibly can.
Of course things are still primitive in neuroscience regarding consciousness. But if a step is conveniently being skipped to render modern theory supernatural, there should be evidence of this at some point in a natural world.
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“For example, what exists which produces no EM radiation (such as the proper symbols written extremely fast)”
I think one thing that would prove EM field involvement would be if there were some way to dampen the EM fields in the brain, If most or all indicators of consciousness were gone or the neurons stopped firing with the same degree of synchronicity then involvement of EM fields would definitely be in the loop in some way.
There are some positive indications that external magnetic fields applied to the brain do have effects but this doesn’t prove the endogenous EM fields are critical.
“Lead researcher Dr Sarina Iwabuchi (Nottingham) said; “We found that one session of TMS modifies the connectivity of large-scale brain networks, particularly the right anterior insula, which is a key area in depression.”
“With more powerful apparatus now available, TMS can be administered at frequencies up to 60 cycles a second (60 Hz). Although there is considerable individual variation, lower-frequency signals apparently lower blood flow and suppress activity in the cerebral cortex, while higher-frequency signals, above 20 Hz, have the opposite effect. By varying the frequency of the pulse and the position of the coil, researchers can turn different brain regions on and off and study how they are involved in vision, motor control, memory, attention, and language.
For example, by placing the coil over the motor cortex, they can make a thumb twitch or a leg jerk to learn more about how the brain controls the body’s muscles. They can also temporarily block or enhance some aspect of vision or speech. Previously, the only way to stimulate small regions of the brain directly was to apply electrodes during surgery.”
“In this study, we show that static magnetic fields applied to visual cortex of awake primates cause reversible deficits in a visual detection task. Complementary experiments in anesthetized cats show that the visual deficits are a consequence of a strong reduction in neural activity. These results demonstrate that SMS is able to effectively modulate neuronal activity and could be considered to be a tool to be used for different purposes ranging from experimental studies to clinical applications.”
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“In fact I think a great case can be made that this generic information possibility would need to invoke supernatural dynamics.”
The logic here appears to be that imagining how neural processing produces conscious experience is difficult, therefore any assertion that it does is an invocation of magic. I would say invoking a “physical mechanism” that you have no evidence for and can’t provide any causal description of, is simply invoking the supernatural and appending the adjective “physical” to it.
“Of course things are still primitive in neuroscience regarding consciousness.”
There remains an enormous amount to learn, but everything that is learned reduces uncertainty about what will be learned in the future. Galileo’s views of the solar system were far less accurate than ours, but he knew enough to rule out Ptolemy and Aristotle’s cosmology. He knew there was little chance that the crystalline sphere’s would turn out to exist after all, or that heavenly bodies would still turn out to be made of quintessence.
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EM fields are not just a randomly chosen “physical mechanism”.
They do exist in the brain. Application of external electromagnetic fields does affect the firing the neurons. Fields provide the one physical thing that is not localized to one part of the brain and could span the brain potentially filling the gap in explaining how consciousness feels to be unified and integrated across multiple sensory organs, memories, and imagination.
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Sorry James. My response to Eric was in the context of an ongoing conversation he and I have been having. It wasn’t meant specifically to be about the EM field proposition. I shouldn’t be doing it on your blog, so I’ll let Eric have the last word and drop this topic.
On the fields, yes, they exist, and yes, they can be affected with things like TMS. However, EEG readings outside the scalp are in terms of microvolts, while those directly in neural tissue are in terms of millivolts. (Which fits since the action potential is 40 millivolts.) My understanding is that a TMS pulse is typically around 250 volts to induce a differential in the tissue of a few volts. In other words, it’s far stronger than what neural tissue typically emits.
That said, I’m not well read in this area. That’s from a brief Google investigation a while back, so if you have more reliable numbers, I’m totally open to being corrected.
The problem is messy from an experimental standpoint.
My simplistic understanding is (correct me please if I get something wrong):
1- EEG measures voltage changes (often called brain waves but not really waves) between points on the scalp.
2- The voltage changes at the scalp represent neurons firing deeper in the brain but the voltage is much weaker because it has to pass through the brain and skull to get the scalp.
3- Neurons firing are similar to electrical current running in a wire so they do produce a electromagnetic field.
4- MEG measures actual electromagnetic brain waves.
My understanding is that the skull/brain case acts like a Faraday cage effectively shielding the brain from most external EM radiation so that a large voltage to cause a small change would not be surprising. That would not necessarily be the case with EM generated inside the brain.
I see from your discussion with James that you’re giving me the last word on this matter for now and dropping it. This is understandable given how extensively we’ve gone through this in the past, and certainly in quite recent discussions.
I brought my “dual computers” model to your blog in 2016, just before the election of Trump. Given your affinity for standard “software based” models, only later would I realize how contrary it would be for you. It was last year at Wyrd’s that I got a sense of this given the strength of your opposition for John Searle’s Chinese room thought experiment. In December here with James this went further while we were exploring the idea that consciousness exists as neuron based EM fields.
For whatever the reason apparently Searle hasn’t done a good enough job illustrating why phenomenal experience should be considered more than a function of just “software”. I suspect that the arguments which I’ve developed in discussions with you would be more effective than his, which adds to an extensive list of ways in which I’d like to help improve academia. I’d very much like to go through this matter with other intelligent people, and so potentially begin to challenge the status quo.
Actually the logic is that theorizing that information alone creates phenomenal experience, with no associated output mechanisms to animate, simply cannot be sufficient in a causal realm. Here countless scientists seem to be conveniently disregarding a crucial final step. Just as a computer simply cannot produce any screen images without at least being hooked up to a screen, a computer should also not produce any phenomenal experience without at least being hooked up to something which is set up to produce it. EM radiation does seem very well suited to serve such a role.
My point however is that here we’re at least proposing something which respects causality. While the symbols that Superman writes with pencil and paper should not produce what I experience when my thumb gets whacked, since they’re just symbols, they may indeed have this effect if interpreted by a machine which is set up to animate Superman’s writings. Here the conceptual circle would at least be complete.
To me it’s interesting that you mentioned the time of Galileo, since that’s roughly where I’d put modern speculation regarding consciousness.
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