Tag Archives: sleep

Mark Twain’s Daily Routine

26 Friday Jul 2013

Posted by in Literature

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Mark Twain

“In the 1870s and ’80s, the Twain family spent their summers at Quarry Farm in New York, about two hundred miles west of their Hartford, Connecticut, home. Twain found those summers the most productive time for his literary work, especially after 1874, when the farm owners built him a small private study on the property. That same summer, Twain began writing The Adventures of Tom Sawyer. His routine was simple: he would go to the study in the morning after a hearty breakfast and stay there until dinner at about 5:00. Since he skipped lunch, and since his family would not venture near the study—they would blow a horn if they needed him—he could usually work uninterruptedly for several hours. ‘On hot days,’ he wrote to a friend, ‘I spread the study wide open, anchor my papers down with brickbats, and write in the midst of the hurricane, clothed in the same thin linen we make shirts of.’

After dinner, Twain would read his day’s work to the assembled family. He liked to have an audience, and his evening performances almost always won their approval. On Sundays, Twain skipped work to relax with his wife and children, read, and daydream in some shady spot on the farm. Whether or not he was working, he smoked cigars constantly. One of his closest friends, the writer William Dean Howells, recalled that after a visit from Twain, ‘the whole house had to be aired, for he smoked all over it from breakfast to bedtime.’ Howells also records Twain’s difficulties getting to sleep at night:

In those days he was troubled with sleeplessness, or, rather, with reluctant sleepiness, and he had various specifics for promoting it. At first it had been champagne just before going to bed, and we provided that, but later he appeared from Boston with four bottles of lager-beer under his arms; lager-beer, he said now, was the only thing to make you go to sleep, and we provided that. Still later, on a visit I paid him at Hartford, I learned that hot Scotch was the only soporific worth considering, and Scotch whiskey duly found its place on our sideboard. One day, very long afterward, I asked him if he were still taking hot Scotch to make him sleep. He said he was not taking anything. For a while he had found going to bed on the bath-room floor a soporific; then one night he went to rest in his own bed at ten o’clock, and he had gone promptly to sleep without anything. He had done the like with the like effect ever since. Of course, it amused him; there were few experiences of life, grave or gay, which did not amuse him, even when they wronged him.”

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From the section devoted to Mark Twain, one of the finest Americans to ever breathe, from Mason Currey’s book Daily Rituals: How Artists Work.

The Function of Sleep

21 Tuesday May 2013

Posted by in Psychology, Science

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Giulio Tononi

“Among the open questions in neuroscience, I believe the function of sleep remains perhaps the most embarrassing. We don’t know why every night our brain needs us – and presumably itself – to sleep for several hours. There is every indication that sleep performs an essential function, if we only knew which one.

The indications are that sleep is, first of all, dangerous. Obviously you are made vulnerable to predators if you fall asleep and don’t respond to stimuli. It is pervasive; we do it from the cradle to the grave. It is universal: every animal that has been carefully studied does so – from fruit flies to ourselves. There is no single exception. It is also irresistible, as we all know. If you do experiments to keep animals awake – or humans awake, for that matter – there is no way that you can overcome the need for sleep. You can even use pain, shocks — at some point the animal will fall asleep. It is also tightly regulated, with a big portion of the brain stem, the hypothalamus, all kind of complicated connectivity being set up to put ourselves to sleep and then wake us. And finally, if you don’t sleep, or sleep too little, it is clear there are serious consequences. In fatal familial insomnia, after a few months of lack of sleep, you die. Rats die after two weeks. But the most obvious consequences are cognitive consequences. There are all kinds of problems. We become extremely bad cognitively. We make mistakes of all sorts, and we become extremely irritable…

The enigma of sleep function has been around for a long time. All kind of ideas have been proposed. The theory I propose is the synaptic homeostasis hypothesis, which is an attempt to understand what is the core function of sleep in every animal.

The idea here is, in short, that sleep is the price we pay for plasticity, which of course is a feature that is functional primarily when we’re awake, when we adapt to the external world.

In our brains, neurons either spike or they don’t — that’s how they communicate. Spikes are more expensive than non-spikes in terms of their synaptic consequences, in terms of the energy they use. So spikes should be reserved, and as far as we can tell they largely are, to signal important events — events that convey a lot of information. Now, when you need to adapt to a changing world — which is basically all the time, especially during development — what you need to do is shift strength of synapses or even add synapses to make sure you are firing for important events or important changes in the environment.

And every neuron does that, to make sure it signals important stuff downstream, in this complicated brain where every neuron is immersed in a sea of other neurons. It doesn’t know what it’s getting, or from where; it doesn’t know what it’s signaling, and it doesn’t know where it’s sending it.

So, in all of this uncertainty, for any learning system which is as complicated as a brain, there is a problem in the end, which is that neurons tend to strengthen to make sure they signal. But then that becomes biologically untenable, because stronger synapses consume more energy, occupy more space, require more supplies, and finally they saturate signal to noise.

Basically, then neurons start firing for everything, and that can’t be good. So there is a need for renormalization to make sure that total synaptic strength is constant.

And we think that that renormalization is not only essential, but it better happen offline, when you actually can sample in an unbiased way the environment of a neuron. And every neuron, by itself, does this in the course of a night’s sleep.

That’s what we think sleep is fundamentally for.”

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From Dr. Guilio Tononi’s recent talk on The Function of Sleep at the Allen Institute for Brain Science Symposium.

I had never before seriously considered this question of the purpose of sleep, or the sheer strangeness of the fact that we don’t yet have a firm understanding of its biological function. It’s nothing less than absurd to ponder what happens to me, to you, to everyone as we spend one third of our lives unconscious.

As Neil deGrass Tyson observed, “Aliens might be surprised to learn that humans must lay semi-comatose on cushions for nearly a third of every Earth rotation.”

Craig Raine, in his poem “A Martian Send A Postcard Home,” mimics the voice of a martian who is noting different facets of human life and reporting them back to his kind. These take the form of riddles, the last one being a coded reference to human sleep and dreaming:

At night when all the colours die,
they hide in pairs

and read about themselves —
in colour, with their eyelids shut.

Watch Tononi’s entire talk below.