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Comment by slver | Hacker News Reader

I can list a bunch of trivial reasons why we sleep, about memory and so on. I can also give trivial explanations like "it's because you're tired and you get rest".

But I wonder if anyone has explained why typing coordination would be worse without sleep. This is a mechanical task where analytical thinking and so on are not involved, just simple motor memory patterns.

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The book Brain Rules by John Medina is worth checking out for some suggestions on possible answers. I don't think science has definitive answers yet but if I remember correctly it's thought that the circuits involved in what the brain learned during the day are active during certain sleep stages which helps with consolidation of memory due to strengthening of connections involved. It's 10 years since I've read into this but I think the biology involved was that oligodendrocytes lay down thicker myelin on axons that are active, resulting in faster/stronger connections in the circuits involved. There's also inhibitory actions of established networks which have to be overcome by new circuits which takes sustained 'attack' over time. If the inhibition didn't happen the previously learned activities would turn noisy very quickly so there's a tradeoff between learning speed and maintenance of high fidelity signal for existing pathways in the brain. I guess the brain has evolved to accept new networks from actions that are repeated and thought about repeatedly because these generally are important whereas stuff that is thought about only once probably isn't.

Playing piano doesn't require analytical thinking either. Motor memory is just another set of patterns, and rest helps establish the patterns in our mind.

I feel we need to flesh that out more. Because if we just say sleep establishes the patterns, it's almost as if we say a pianist who has been playing for decades forgets how to be a pianist without a day of sleep, and then while sleeping he remembers how to be a pianist.

I feel I need a more detailed explanation here.

Apparently something gets depleted from the brain during the day, that we get back during sleep. Maybe it's structural, not chemical, but something gets depleted.

In the aforementioned anecdote, the pianist was struggling with a new composition, not general piano skills. Which would make sleep a catalyst for making new neural pathways for that specific composition, not how to be a pianist in general.

That's my take as a layman.

Learning a new piece usually requires learning novel movements, stuff you've never done before. Maybe you've played a C major before, but you don't always use the same fingers depending on where you're coming from and where you're going, maybe the cadence or intensity is different, and so on.

Still, I can witness myself if I haven't slept well not only my ability to figure out complex programming code suffers, but the mere ability to type fast without a ton of typos.

Otherwise I agree after sleep, what we learn seems more readily available.

I'm not sure that's entirely true. There are many ways to approach playing piano, although they all require muscle memory there's a huge cognitive portion to improvisation for example. Some do that by feel, and some do that by actively thinking about the theory they're playing.

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