The Work We Do While We Sleep
newyorker.com
newyorker.com
When we sleep, our brains process the events of the day and pick out things to stow away in our long term memory.
Maybe as a side-effect of this processing, they also aid problem solving - after a good night's sleep, you are able to find solutions to the previous day's problems faster (than you would, if you hadn't had the sleep).
As we sleep, our brains clear away toxins that accumulate during our awake time. These toxins may be culprits behind neuro degenerative diseases.
There seems to be a correlation between sleep deprivation and cardiovascular diseases.
This is an interesting side effect considering when I have a tough coding problem, it keeps my brain churning for hours and it keeps me from falling asleep.
It's clear your subconscious comes to the forefront as your conscious part of your brain turns off during sleep. Having your subconscious solving complex problems is fascinating to me. I'm wondering how you could activate this on purpose, without having these issues keep you awake at night when you consciously can't let go of a problem.
The implications of this are pretty cool if you could pull it off.
Sleep also definitely has a large effect on mood, I assume at least partly through the mix of stress hormones produced; many people I have known closely become extremely emotional and irritable when they haven’t had enough sleep. Others become emotionally detached/withdrawn (at least, by outward appearances).
I wonder if, a long time ago, some animal evolved the ability to enter brief periods of elevated activity. This was obviously highly advantageous for e.g. escaping predators, so over time this animal evolved to sustain this temporary boost for longer periods. Today, animals can sustain this boosted state for the majority of their lifetime. It is merely a matter of perspective that leads us to consider wakefulness to be "normal" and sleep to be something out of the ordinary.
The obvious advantages of not sleeping indicates to me that there is a deep connection between sleep and our waking performance. If there weren't why the hell would it have persisted across so many creatures for so long.
I am confused by the fact that human young keep parents awake so much: it seems like a delicate time to be introducing poor cognitive performance into the mix.
But then a lot of things confuse me when I apply straight forward darwinian thinking.
Since we can barely see in the dark and can't do anything anyway, wouldn't it be preferable to minimize the time spent defenseless against predators with better night vision? Staying still seems like a good strategy a lot of times, when most animal visions, night vision or not, is based on movement.
It doesn't answer, though, why the top of the food chain need to sleep too.
Thus, there exists a solution in nature wherein the creature experiences the benefits of both regular sleep and continuous alertness. The rarity of the solution suggests that sleep is more important for most mammals, except in niches where a prolonged loss of consciousness could lead to drowning, or being eaten by sharks.
Also recall that as social, tribal animals, modern humans relied on aunts and grandmothers to relieve exhausted mothers for all of prehistory. Separate homes for smaller family units and wider geographic dispersal of family members are relatively recent developments. I wouldn't expect biological adaptations to the practice to appear any time soon. I think the most likely event is that we will discover and use a pharmaceutical remedy for sleep deprivation in parents, possibly by studying dolphin brains.
Intro: http://www.researchgate.net/publication/271920141_The_Viscer...
Cortical visual areas process intestinal information during slow-wave sleep: http://onlinelibrary.wiley.com/doi/10.1111/nmo.12052/abstrac...