Tag Archives: Neuromodifiers

Ecstatic About the Glymphatic

Let’s talk about sleep (baby, let’s talk about you and me, let’s… no? no. fine). More specifically, let’s talk about how sleep is très importante, because the waking world is TOXIC.

Wrong Toxic

Yeah, I went there.

Really, though. Research done by a Whole Buncha Scientists™ has shown that the very state of being conscious results in a buildup of harmful waste proteins (which our prof called “metabolic toxins”). Being awake = harmful to your health? Huge surprise, I know. Next time your parents/dogs/kids/significant-others try to get you out of bed, this offers the perfect justification for nailing them in the face with a pillow.

Unfortunately, the waking world is full of fun stuff to do, so we have to engage with it sometime. Luckily, our bodies have this amazing way of dealing with brain toxins- it’s called sleep.

Well, it’s actually called the glymphatic system, but that sounds so much less appealing. The glymphatic system is kind of like the brain’s plumbing apparatus; at night, when we sleep, it pumps cerebral spinal fluid (CSF) through the brain’s tissue, flushing the waste toxins right out of the brain. To facilitate the process, your brain cells actually reduce in size so that the waste can be removed more effectively.

Our brains actually shrink during sleep- how crazy is that? I knew there was a reason I’m not a morning person.

Dr. Maiken Nedergaard, a professor of neurosurgery at the University of Rochester and author of the study in Science, says that this could explain “why we don’t think clearly after a sleepless night and why a prolonged lack of sleep can actually kill an animal or a person.”

So if this whole removal of brain-killing toxins thing is so important, why doesn’t our slacker-ass glymphatic system work more than a handful of hours overnight? Well, apparently the whole shrinking your brain and circulating CSF through your brain to your liver thing takes a lot of energy. The glymphatic system is minimally active when we’re awake, but it’s ten times more active when we’re asleep. Check out the image for a look at the difference.

courtesy of The Independent
The Glymphatic System at Work

Dr. Nedergaard notes: “You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can’t really do both at the same time.”

At least, not without inviting the glymphatic system, as well. Talk about a party pooper.



Side note: The articles at NPR and The Independent (below) talk a bit more about the implications of all this for diseases like Alzheimer’s, which may result, in part, from a build-up of certain kinds of metabolic waste in the brain. For my purposes, I’m going to hold off until next post, and then muse on how this may all affect the process of learning and the recording of memory.



1. NPR: http://ow.ly/AfFX8

2. The Independent: http://ow.ly/AfG1d



1. Toxic: http://ow.ly/Ai86e

2. Glimpse of the Glymph: http://ow.ly/AfG1d




I know I said that the next blog post would be about sleep, but I read this article in the BBC today (http://ow.ly/AeYgh), and was delighted by how well it related to things I’ve been learning about focused/diffused thinking. I mean, yawning as a brain-hack to higher function of attention?

Back up.

In class last week, Prof. Oakley differentiated between two modes of thinking: focused and diffused. When your mind is focused, you’re concentrating intently on trying to learn/understand, and your thoughts move smoothly along familiar pathways. Diffused thinking, on the other hand, is a broader, more creative mode of thought (similar to daydreaming). Diffused thinking allows you to draw new parallels, make new neural connections; focused thinking drills those thoughts into your mind and cements the neural pathways.

The two modes seem wonderfully complementary… but the downside is that you cannot be in both modes at the same time; being in one mode necessarily limits your access to the other. It’s not always easy to switch modes, either (as testified by anyone who’s tried to answer a question from a chatty roommate while “in the zone,” or tried to break out of an in-class daydream to answer a question from a professor). Some of the great artists and thinkers tried to more perfectly utilize both modes by building their own mind-traps.

Salvatore Dali, for example, used to daydream with a set of keys held loosely in his hand. As he drifted toward sleep, his hand would loosen, dropping the keys on the floor and startling him awake. He could then quickly take advantage of the thoughts and images he had had while daydreaming, before they slipped out of his working memory in sleep. Thomas Edison did the same thing with a set of loose ball bearings. Even today, numerous creative specialists advise placing pen and paper nearby when you go to bed, so that you can capture any thoughts that come to you as you drift in and out of the diffuse mode near sleep.

David Gahr/Getty Images
Dali: the man wears a moustache like it’s a verb. (David Gahr/Getty Images)

Anyway. All this is to say that one of the keys to creative thinking and analogical learning is the ability to switch between the diffuse and focused modes of thinking.

And now, scientists may have the way to create this key: yawning.

Say what?

I’m serious. Recent research by Andrew C. Gallup and Omar T. Eldakar (http://ow.ly/Af8at) suggests that yawning may serve a thermoregulatory function in human beings. I.e., your brain heats up, so you yawn. The rush of blood caused by your flexing jaw combines with the cool air in your sinuses to turn down the cranial thermostat… coincidentally (or not) also flushing your brain with cerebrospinal fluid that washes away some of the somnogenic factors like prostaglandin D(2) and adenosine, among others (see: Walusinkski, http://ow.ly/Af7Vl).

So what does this mean for thinking? According to Gallup and Eldakar, “yawning actually serves to maintain focus and attention, thereby antagonizing sleep” (p6). By cooling you down and flushing neuromodifiers like adenosine out of your system, yawning helps you transition more quickly from a sleepy, diffuse-thinking state into a more wakeful, focused one. It’s like a brain hack- a shortcut allowing you to bypass the dreamy moments when you might forget your diffusely-inspired epiphanies and go straight to the process of recording your brilliance for posterity.

(Though you may never achieve the heights of effervescent moustachery exhibited by the thinking-mode masters of yore. )

How can we practically take advantage of this research? Well, next time that professor interrupts your deliciously dreamy diffuse imaginings in class, give her a big old yawn in the face. She’ll understand that you’re just flushing your neocortex and cooling down in order to give her question all of the focused attention it deserves.