Comment by pedalpete
2 days ago
I work in neurotech with auditory stimulation, so you'd think I'd be a big fan of this area of research, and I think the authors have done a decent job of suggesting the limitations, but the title itself gets picked up and people read a lot into what they think this is saying. Or maybe I'm just a bit jaded.
They provide a 2.4 Hz stimulus and then measure frequency-matched activity across brain networks. They suggest some novel methods of measuring how the signal traverses the brain, but they don't suggest why it does, which is good. They do say this is unlikely to be entrainment, I'll get into that more in a bit.
We shouldn't be surprised that auditory stimulation produces frequency-matched activity across distributed brain regions. The auditory system naturally routes information across multiple interconnected networks. The auditory system picks it up, but the auditory system is also not siloed into a single area of the brain. No brain systems are, we have replication, and this is just showing the the nervous system is passing the signal throughout the brain. In no way does it suggest that this is related to thought, consciousness, focus, or that these frequency-matched responses reflect any functional change in brain state.
When people talk about entrainment, that is a real thing. But the word itself describes when systems synchronize, not that they will.
I guess I'm cautious about papers like these because of our work in neurostimulation and sleep where we use phase-targeted auditory stimulation to enhance slow-wave activity. Basically increasing sleep's restorative function.
In our work it isn't this sort of "gentle tones to help you sleep", or "activating networks to alter brain activity", which is an area I see a lot of snake-oil and nonsense.
The way closed-loop phase-targeted slow-wave enhancement works is by "interrupting" the brain during the synchronous firing of neurons, which (it is believed) triggers a protective mechanism in the brain and as a response, the brain increases the synchronous firing of neurons. We're talking about very short (50ms) interruptions.
I get my back up a bit when I hear about this idea that reading electrical activity of the brain and making broad assumptions about what they "mean". I've been invited to speak on a panel July 2nd with Australia's Commissioner of Human Rights to discuss ethical safety around EEG data, and while I do believe we need to protect bio-data, I don't believe in the "electrical activity means we can read or alter your thoughts" camp.
If you want to know more about our work, you can check out https://affectablesleep.com, and if you're in Sydney, and want to come to the talk, I can't find a link atm, but it's at the Sydney Knowledge Hub on July 2nd., part of the Sydney Neurotech Meetup
Maybe you would know or have an opinion. I see a lot of articles about rewiring your brain. For instance, the affects from meditation, or book reading. And how those things can rewire your brain. But does it matter? If it's relatively simple rewire your brain(simple as in, doing an activity for several months). It appears to me, that your brain adapts, and that adaptation is normal. Struggling to completely put this idea into words, but isn't this more like saying, 'if you lift this weight your muscles grow!', and then selling that as if its some sort of miracle?
Neurons definitely re-wire, or just wire/connect. Meditation, creates an understanding of how we can "control" or monitor our thoughts. Reading creates understanding.
Yes, if you lift the weight, muscle will grow. If you look at or think about the weight, studies suggest, muscles will also grow.
But I'm cautious to not conflate "we see electrical activity" to "we have re-wired the brain".
Meditation changes the electrical activity, but we don't put an electrical signal into the brain and end up with meditation. We can kinda force the brain into a meditative state with magnetic stimulation, but we're talking about some really powerful stuff, and I think some would argue that we aren't actually creating a meditative state if we were to do this. Note: I haven't looked into this too deeply.
The way I look at it, we are just really clever apes. We keep thinking we understand how the brain/body/consciousness works, but every time we discover another layer of science and understanding, we look back at our previous understanding and think how naive we were. I think this is the same.
We used to literally think we understood how the body worked by "balancing the 4 humours". We understood how blood delivered oxygen to muscles and nutrients and we thought "oh, I get it, it's a big pump, and we pump this blood stuff around and that's how it works". Then we discovered electricty, slapped our collective foreheads and went "OH!! Of course, it's electric! electricity contracts the pump, oh, and look at these thing in the brain! They're electric too!! I get it".
Soon, we'll go through this whole process again and realize that the electrical activity wasn't wrong, but was naive, and I suspect the process will repeat again, and again.