[Image: Fish preserved in the eternal ocean of a closed jar at the American Museum of Natural History; old Instagram by Geoff Manaugh].
Although this is a classic example of something I am totally unqualified to talk about, a recent report over at ScienceNews caught my eye, about the spatial origins of REM sleep.
In a nutshell, the paper suggests that “sleep may have originated underwater 450 million years ago,” which is apparently when “the cells that kick off REM sleep” first evolved in fish. “During REM or paradoxical sleep,” we read, “the brain lights up with activity almost like it’s awake. But the muscles are paralyzed (except for rapid twitching of the eyes) and the heart beats erratically.”
Dreaming, it’s as if ancient fish learned to pass into a different kind of ocean, a fully immersive neural environment coextensive with the one they physically swam within.
What’s so interesting about this—at least for me—is the implication that REM sleep, and, thus, by extension, the very possibility of animals dreaming, was made possible by immersion in an all-encompassing spatial environment such as the sea. In other words, it took the vast black depths of the ocean to facilitate the kind of uninterrupted, meditative stillness in which REM sleep could best occur. Those ancestral cells then survived into our own mammalian brains, and, by dreaming, it’s perhaps a bit like we retreat back into some lost experience of the oceanic.
[Image: “Sleeping Beauty” by Hans Zatzka].
In any case, the study’s authors are probably rolling their eyes at this point, but so much comes to mind here—everything from H.P. Lovecraft’s marine-horror stories and their alien call of the deep—such as “The Shadow Over Innsmouth”—to the speculative idea that there might be other spatial environments, comparable to the ocean, that, after long-enough exposure, could inspire unique neurological processes otherwise impossible in traditional environments.
I’m thinking of Jeremy Narby’s strange book, Cosmic Serpent: DNA and the Origins of Knowledge, about human culture amidst the impenetrable rain forests of the Americas, or even the long-running sci-fi trope of the human mind expanding in a psychedelic encounter with deep space.
In fact, this makes me wonder about the landscapes of other planets, and whether crushingly powerful gravitational regimes in alien superstorms or bizarre swirling ecosystems deep inside liquid rock might affect the neurological development of species that live there. What other kinds of sleep are environmentally possible? Does every planet come with a different kind of dreaming? Can the design or formation of new kinds of space catalyze new forms of sleep? Are there deeper or higher levels of the brain, so to speak, waiting to appear in radically different spatial environments?
We already have astrobiology, astrogeology, even astrolinguistics, but I wonder what it would look like to study sleep on other worlds. Exosomnology.
4 thoughts on “A Spatial History of Sleep”
Very interesting and puts me in mind of Valentin Lebedev’s “Diary of a Cosmonaut”, where he describes falling asleep in orbit. He and his fellow astronauts found that when drifting off, if they concentrated hard enough on the face of a loved-one, occasionally the person’s image would flash with a super-real vividness. The cosmonauts regularly performed this as — after hundreds of days in space — they found it comforting to conjure the people they missed. Lebedev wondered if some type of cosmic radiation resonated with his neurons like a kind of spectrometer. Dipping into another spatial dimension would be a much more exciting explanation though…
Vertebrates aren’t the only animals that sleep. Insects do as well. Fruit files sleep, but not all of them are harmed by the lack of sleep. The more sociable types of fruit flies do need sleep, a lot more than the less sociable ones. Do they dream? I have no idea, but the need for sleep being linked to sociability suggests that they do use their sleep to do something to their brains.
I am reminded of the opening scene of The Shape of Water film. Eliza played by Sally Hawkins is asleep, floating above her sofa in her living room full of water.
It’s actually weirder than you think. We use the same spatial brain mechanisms, our grid cells, for mapping categories and concepts as we do for mapping space. In the paper, “Organizing conceptual knowledge in humans with a gridlike code” Science 17 June 2016, they made up a space of parametric birds with different length necks, legs, bodies and so on, and they used fMRI to show that there is a grid like mechanism in the brain for determining where a bird lies in that space. The same mechanism that lets fish navigate the ocean also lets us understand the meanings of the various synonyms one might find in a thesaurus or recognize that an unknown scent has citrus notes.