An article by Maria Konnikova in the New York Times provides an informative overview of recent work on sleep's role in our "brain's physiological maintenance." As reported in Sleep Cultures ("We sleep to clean our brains"), a team led by Maiken Nedergaard at the University of Rochester medical school have proposed that the sleeping brain is cleared of its daily build-up of toxins and celluar waste by what they call the "glymphatic system" -- a "network of channels that clear[s] out toxins with watery cerebrospinal fluid."
Konnikova contextualizes her discussion with some interesting reflections on the function and history of sleep. She begins by noting, as many have done before her, that sleep is, on the face of it, an enormous -- and quite possibly dangerous -- waste of time. Here she echoes Allan Rechtschaffen's famous observation that, if sleep serves no absolutely vital purpose, then it is the greatest mistake evolution ever made. Happily, the notion of sleep as a cerebral clean-up operation, one that could not be performed while the brain is awake and attending to other matters, provides this apparently passive state with just such a sense of purpose. Indeed, the striking metaphors that Konnikova uses to describe sleep -- she calls it our "mental janitor" or "neural housekeeper" -- are indicative of the extent to which we tend to value sleep only inasmuch as it can be re-imagined as a form of labour. And if sleep is a kind of work, then, like all labour, it can be performed more efficiently. Konnikova ends the article by speculating about the possibility of new drugs that will "promote the enhanced cleaning power of the sleeping brain in a brain that is fully awake." Which is to say that at present sleep has a vital job to do, but its employment prospects are precarious; it may be only a matter of time before its cleaning duties are outsourced to wakefulness.
Konnikova contextualizes her discussion with some interesting reflections on the function and history of sleep. She begins by noting, as many have done before her, that sleep is, on the face of it, an enormous -- and quite possibly dangerous -- waste of time. Here she echoes Allan Rechtschaffen's famous observation that, if sleep serves no absolutely vital purpose, then it is the greatest mistake evolution ever made. Happily, the notion of sleep as a cerebral clean-up operation, one that could not be performed while the brain is awake and attending to other matters, provides this apparently passive state with just such a sense of purpose. Indeed, the striking metaphors that Konnikova uses to describe sleep -- she calls it our "mental janitor" or "neural housekeeper" -- are indicative of the extent to which we tend to value sleep only inasmuch as it can be re-imagined as a form of labour. And if sleep is a kind of work, then, like all labour, it can be performed more efficiently. Konnikova ends the article by speculating about the possibility of new drugs that will "promote the enhanced cleaning power of the sleeping brain in a brain that is fully awake." Which is to say that at present sleep has a vital job to do, but its employment prospects are precarious; it may be only a matter of time before its cleaning duties are outsourced to wakefulness.
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