From Brain Science Podcast - Episode 187 - The LiveWired Brain
The LiveWired Brain - Dr. Ginger Campbell Interviews Dr. David Eagleman
A discussion of Livewired: The Inside Story of the Ever-Changing Brain
“So, I call this “livewired” to distinguish it because it’s a system that’s actually changing its own circuitry on the fly.”
Dr. Ginger Campbell has been hosting the Brain Science podcast monthly for 187 episodes. This month she interviewed bestselling author and neuroscientist David Eagleman’s about his latest book Livewired: The Inside Story of the Ever-Changing Brain. The conversation includes an overview of our current some interesting speculations about the nature of memory, dreaming, and - most relevant to Feldenkrais students - how current neuroplasticity research is catching up with Dr. Feldenkrais.
Below are some excerpts I found particularly interesting.
On Nature (DNA) verus Nurture (Experience)
Dr. Eagleman: Generally, the way I look at DNA now is it is the thing that sets up the system. It's the first domino that kicks off the whole show, but really, what it is setting up is a system that is livewired. It's building a system that will then go out and absorb the world around it.
On the Brain’s Constant Reconfiguring And Our Limits in Measuring It
Dr. Eagleman::[T]o me, the most gorgeous probably least talked about in terms of popular science aspect of the brain, is its massive flexibility and the way that it's constantly reconfiguring every moment of your life.
So, with everything that you hear and experience and see, and so on, you've got your 86 billion neurons and your 200 trillion connections between them and they're just constantly reconfiguring.
So, now, this concept of brain plasticity, this is something most everybody knows about, so I'm not implying that it's an unknown. But there's not much to talk about because there's so much mystery there. And the reason is our technology really isn't good enough to measure what's happening at the level of these very tiny connections.
[I]t turns out we pretty quickly discovered that it's not genetically pre- specified because if you let's say, lose an arm or you're born without legs or something like that, the map of the body reflects what's going on there. So, what that means is, for example, if you lose an arm, the part in your brain that represents an arm, gets taken over pretty rapidly by the neighboring areas. So, what that means is, it's experienced dependent. It depends on the amount of activity coming in, and that's how your brain puts together from its mission control center in darkness, a sense of what's going on with the body and what muscles it can drive. And so, it's a very flexible system.
On How Quickly the Brain Adapts to New Circumstances
Dr. Eagleman:: [I]f you take a sighted person and you put them in the scanner and you blindfold them tightly, what you see is that the visual cortex at the back of the head starts responding to signals of hearing and touch within about an hour, which is much faster than anyone would have guessed.
Now, obviously, it's not growing new connections, new axons from the neurons into that area. Instead, one thing that we know is that the brain is heavily cross-wired. So, you have neurons from the auditory cortex and from areas involved in touch and so on, and these are reaching all around.
But what happens is when there's no more visual information coming in, suddenly, the brain says, “Oh, I guess there's no more visual information coming in. That's fine. I guess we'll start taking over that territory, that is otherwise going to be lying fallow.”
On Dreaming: The Brain Making Sure the Visual Cortex Stays Engaged, Even in Darkness
Dr. Eagleman:: Anyway, it turns out that this can happen really rapidly and what my student and I realized as soon as we read that paper was, gosh, the problem is that the planet rotates into darkness for 12 hours out of every 24. That means that the visual cortex would be in danger every night of getting taken over by hearing and touch and other things.
And so, what we realized is this is actually the basis for dreaming. The reason we dream at night is because these very sophisticated mechanisms in the brain that are hardwired in there, every 90 minutes or so, become active and slam activity back into the visual cortex.
David Eagleman, PhD. Image source: brainsciencepodcast.com
And if you look up the circuitry for dreaming, you'll see that it only goes into the visual cortex and that's it. Because it's the visual cortex, we’ve of course, interpreted it as visual. And presumably, the content of dreams has to do with whatever synapses are hot from whatever you've experienced in the daytime.
So, the point is you get this activity that's slamming back into the visual cortex every 90 minutes, and we interpret it as seeing stuff. And because the brain is a great storyteller, we impose narrative on top of that, and we wake up and we say, “Oh my gosh, I just had this weird experience.” But the point is, it is the visual system's way of defending itself against takeover from the neighboring areas.
And so, we've now researched, and for example, we compare very carefully, 25 different species of primates and looked at how flexible their brains are or how plastic their brains are, and how much dream sleep they get every night as measured by rapid eye movement (REM).
Dr. Ginger Campbell, Brain Science Podcast
On Maintaining Brain Plasticity As We Age
What the brain is trying to do is develop an internal model of the world and say, “Okay, I got it. I know how this works” and then it doesn't have to do any more change. That's all it's trying to do; is get to a point where it doesn't have to change anymore.
And one of the interesting things about the pandemic has been that all of us got knocked off our hamster wheels back in early 2020. And we've had a lot of brain changes since then, just predicated on needing to figure out what the heck's going on and how to get food in our fridge and what we want to do with our jobs and our lives and how to do things on Zoom and so on.
But the key is, as one gets older, one has to try harder and harder to seek novelty, to avoid one's own dogma, to figure out how to celebrate possibility and try new things constantly, and new things that are in between the levels of frustrating, but achievable.
So, it can't be something that's too easy. Obviously, if it's too difficult, it doesn't mean anything to the brain. But so, people will ask me all the time, “Yeah, what about Sudoku crossword puzzles?” The answer is sure, until you get good at it and then stop it and do something else… [Allow] your brain to get itself off the path of least resistance and having to at least notice things about the world.
The part about dreams being the visual cortex’s way of not losing real estate during darkness - mind blowing. Awareness Through Movement as a way to help the brain continually L:iveWire - no surprise, but love the validation.