Is Sleep a neccessary Biological Function

[Stravo]

I was wondering if it is considered a basic biological function say like breathing that all organisms must sleep. I was brainstorming some ideas for an alien species and thought wouldn't it be cool to have these aliens that never sleep. Would be kind of freaky. But then I wondered if that was biologically impossible for an organism not to have to sleep. Anyone have any thoughts on this?

[Gil Hamilton]

I was wondering if it is considered a basic biological function say like breathing that all organisms must sleep. I was brainstorming some ideas for an alien species and thought wouldn't it be cool to have these aliens that never sleep. Would be kind of freaky. But then I wondered if that was biologically impossible for an organism not to have to sleep. Anyone have any thoughts on this?

For humans and most complex earthly life, absolutely. Aliens are going to be radically different, so they don't necessarily have to sleep if you don't want them too.

[Darth Raptor]

It's possible to have an organism that doesn't sleep per se, but I can't think of an animal that doesn't go through alternating cycles of activity and relative inactivity. Generally, the more sophisticated the brain gets the more important sleep becomes for memory consolidation and such.

Maybe you could have a species that used to sleep in the distant past but has replaced it with a sort of perfected meditation technique? One where they would be extremely quiet and still but still responsive? Human brains are active during sleep cycles so I don't see how it'd hurt to maintain actual consciousness if the other functions were being performed during the altered state.

[Flagg]

I read a long time ago that they did experiments on rats or mice where they forced them to stay awake until they eventually died of sleep deprivation.

[Admiral Valdemar]

When you tell me what sleep is for, I'll tell you whether it's necessary or not. As it is, every organism of macrosize uses it for their brains, so it's safe to say it's pretty fundamental to our physiology, but possibly has a getaround if we can engineer something suitable like resting one cerebral hemisphere at a time.

For humans and most complex earthly life, absolutely. Aliens are going to be radically different, so they don't necessarily have to sleep if you don't want them too.

Sorry, you base this on what, exactly? Aliens aren't going to alter the laws of physics and like it or not, you're going to get carbon based aliens, none of this silicon or "pure energy" bullshit. So depending on what sleep actually does and how advanced their biotechnology is, I don't see why aliens would arbitrarily be without a sleep pattern anymore than an alien wouldn't use DNA.

When you don't sleep, bad things happen, and they end when your life expires unless you get some shuteye.

[Stark]

All sorts of bad things happen to animals when they don't sleep. Perhaps an alien species could simply have a form of sleep that wasn't 'lie down with your eyes closed', since the essential part is purely brain-related. Your muscles don't seem to need sleep (any more than rest) but our brains certainly need constant downtime.

[Rye]

When you tell me what sleep is for, I'll tell you whether it's necessary or not. As it is, every organism of macrosize uses it for their brains, so it's safe to say it's pretty fundamental to our physiology, but possibly has a getaround if we can engineer something suitable like resting one cerebral hemisphere at a time.

That's what I was going to bring up, read it in Consider Phlebas, I think... where there was a captain dude or something that had half his brain sleep at a time while remaining awake with the other half.

[Admiral Valdemar]

That's what I was going to bring up, read it in Consider Phlebas, I think... where there was a captain dude or something that had half his brain sleep at a time while remaining awake with the other half.

That and I'm sure a certain type of hardass marine in WH40k is geneered to have their brains optimised like this, among other things. It would be possible given only 5-10% of the brain is used at any one time and one hemisphere can cover for the other if given adequate time to adjust, which could be learnt from the beginning. The military is mad about Modafinil, so imagine getting past sleep suppressing drugs and going straight to 24/7 alertness in situ of combat. Then, if the brain really has to sort out information or revitalise cells or shift vast amounts of certain chemicals during a specific period of brain activity, it can do it to one half while the other takes over.

This only seems to be higher functions since autonomic systems such as with the hypothalamus aren't interrupted and less complex organisms don't have sleep patterns.

The curious thing is that there are no patterns for sleep duration. Some supposed lesser animals require less sleep than us, others, more. It would seem random how much REM and deep sleep various organisms require.

[wolveraptor]

Dolphins have half of their brain asleep at a time. Giraffes only require about 20 minutes of sleep. I think it mostly depends on the level of activity your creatures undergo at any given point. Should they be highly active, mentally or physically (like us), they may require longer periods of full sleep.

[TheBlackCat]

It would be possible given only 5-10% of the brain is used at any one time

Have a source for this?

[Gil Hamilton]

Sorry, you base this on what, exactly? Aliens aren't going to alter the laws of physics and like it or not, you're going to get carbon based aliens, none of this silicon or "pure energy" bullshit. So depending on what sleep actually does and how advanced their biotechnology is, I don't see why aliens would arbitrarily be without a sleep pattern anymore than an alien wouldn't use DNA.

When you don't sleep, bad things happen, and they end when your life expires unless you get some shuteye.

I base it on the fact that if you are writing science fiction aliens for a story, you can come up with some clever quirk of physiology for their brand of life that doesn't require them to be physically unconscious for extended periods of time in order to remain healthy.

[Stofsk]

It would be possible given only 5-10% of the brain is used at any one time

Have a source for this?

I thought this was a misconception. Something along the lines of '5-10% of the brain is used for cognition, while the rest is for memory storage and autonomic responses' or something. I remember hearing a neuroscientist talk about it, and he said "Yeah, we use 100% of our brains. If we didn't, we wouldn't be able to stand or breath."

Though I would like a clarification. Since my memory is hazy, and I'm not a neuroscientist...

[Gil Hamilton]

We use all of our brains, but alot of it is made up of what is called "white matter", which is basically wiring and base functions. The 10% part that people claim is all we use is certainly the interesting part, but we use the entire thing.

[Admiral Valdemar]

Have a source for this?

No single source, but it is commonly addressed that the "10% myth" as it were was twisted from PET and fMRI scans by neuroscientists years ago to mean that we only ever use 10% of the brain at all. This is something favoured by quacks who love the idea of psychic abilities being manifested when one is lucky enough to be able to control more of their brain than the normal Joe Blow. Depending on what you're doing, a select few areas will be undergoing significant synaptic activity which, as seen in these scans, alters on what your brain is processing be it imagery or kinesthetic motor control etc. It is possible this number fluctuates wildly given that variable, but the average of arounf 10% by volume was the figure picked up upon.

I base it on the fact that if you are writing science fiction aliens for a story, you can come up with some clever quirk of physiology for their brand of life that doesn't require them to be physically unconscious for extended periods of time in order to remain healthy.

Sci-fi, yes. But in reality, which is what I assume we're talking about here given this is SLAM, there are a great many reasons to accept that sleeping is mandatory until we fully comprehend what it's for. So only if there is a proper workaround the mental tiredness barrier, then aliens could be able to go without sleep (and presumably, us too). I wouldn't jump to conclusions just yet, but then we'd have to find aliens first to ask this question, and I'm thinking the first questions won't be on how much REM they get.

We use all of our brains, but alot of it is made up of what is called "white matter", which is basically wiring and base functions. The 10% part that people claim is all we use is certainly the interesting part, but we use the entire thing.

A very good point that I failed to bring up. The brain, in order to have structure, requires glial cells (the so called "white matter") which are 10^12 in number within an adult human. The cells that actually perform mental cognition - the "grey matter" dendritic cells - are only 10^11 in number. So while the majority of the brain is simply there to keep it in a decent shape, the rest of it is for processing, and not all of that is firing at once, else you'd have some pretty funky thermal and EEG readings and probably exhaust body glucose deposits far quicker leading to a heat induced fit or coma.

[LadyTevar]

They may undergo Kelnorim like the Jafar do, or the D&D Elven 'Reverie'. Both are meditative states where the mind sorts thru the experiences of the day and rests the body as well. Both races do have to do this daily, but it's only a fraction of the time needed for sleep.

What you might do for your aliens is have this kind of meditational rest, but make it something they only need every other (standard) day. Maybe in times of necessity they can go for longer, but it would be like a human going without sleep: at some point the 'sleepdebt' has to be paid. The aliens might need to fall into a true sleep when they overextend themselves, especially if you use the idea where they 'evolved beyond' sleep.

[Admiral Valdemar]

There is an interesting thing though with regards to sleep debt. Use of Modafinil can keep you awake and alert for 48 hours or so without the drawback of a caffeine high and crash or similar drug experience. But at the end of the drug's usefulness in the body when it's undergone enough half-lives, the tiredness isn't as bad as if someone tried to stay awake normally for that long which would require around 16 hours of sleep after a 48 hour wake period. It's only half that after taking Modafinil or similar "wakefulness promoting agent", at around 8 hours. No one knows why or whether this has long term effects.

[TheBlackCat]

I thought this was a misconception. Something along the lines of '5-10% of the brain is used for cognition, while the rest is for memory storage and autonomic responses' or something. I remember hearing a neuroscientist talk about it, and he said "Yeah, we use 100% of our brains. If we didn't, we wouldn't be able to stand or breath."

It is a misconception. The fMRI and PET scans you see aren't being used to measure absolute brain activity levels, they are being used to measure activity that is above or below the baseline level of activity (measured earlier). You may only see a few areas "light up" in PET or fMRI, but that is not because those are the only areas that are active. The reason is because those are the only areas whose activity level has changed relative the original baseline recording. What is more, they tend to be averaged over many trials to eliminate noise. So you can't go by fMRI or PET images to determine what parts of the brain are active unless you use the raw data.

For instance, visual processing alone accounts for about 30% of the human brain. So when your eyes are open, even if you are only using a fraction of your visual processing you will still be close to the 10% based on vision alone.

The story I heard about the 10% myth has nothing to do with fMRI or PET, it far predates that. It was back in the early days of brain research. One of the researchers found that only 10% of the brain would trigger detectable motor activity in the patient when stimulated. This somehow got translated into 10% being used at all, when it really only mean 10% of the brain is motor cortex while the rest is used for various other purposes.

[The Silence and I]

When you tell me what sleep is for, I'll tell you whether it's necessary or not. As it is, every organism of macrosize uses it for their brains, so it's safe to say it's pretty fundamental to our physiology, but possibly has a getaround if we can engineer something suitable like resting one cerebral hemisphere at a time.

That's what I was going to bring up, read it in Consider Phlebas, I think... where there was a captain dude or something that had half his brain sleep at a time while remaining awake with the other half.

You remember correctly. That was a strange book...

The guy was human, so the modification that allowed his brain to do that was technological in nature, but as someone else pointed out, Dolphins can do this naturally. An alien race could well have this as an adaptation--it may even be a fundamental part of most macroscopic life on that world. Sort of how the HOX gene is extremely well preserved (mutation free) in all Bilateria here on earth, the genetic code that allows the brain to be half awake and half asleep could be part of something vital to the development of all life above a certain complexity.

[TheBlackCat]

The thing is that if dolphins didn't do this, they would drown. The fact that amongst mammals only ceteceans do this indicates that, at least for mammals, there is some inherent disadvantage to this mechanism. The fact that it could have evolved in other mammals but didn't, even fully aquatic ones like sea otters, indicates that there is some selective disadvantage that prevents it from becoming established in other mammals that don't absolutely require it.

[B5B7]

It is believed that sharks may not sleep - results uncertain at this stage - so if you look up some of the speculations about how they could do this, this should give you some ideas for your aliens.
Here is something from the National Marine Aquarium site in response to someone asking the question about shark sleep:

It depends what you mean by sleep. When humans sleep we are not conscious of what is going on around us, we kind of shut-down for a while and are not able to walk around unless we happen to be sleep-walking. Sharks rest in a different way. They can rest part of their brain while still swimming along, semi-aware of what's around them.

Sharks that are able to stop swimming will settle on the seabed, and species like the British Bullhuss shark actually close their eyes - so they appear to sleep like we do. In our aquarium I have seen two Sandtiger sharks bump into each other nose-to-nose. They were so startled, they both took off at great speed in opposite directions.

This suggested to me that they were dozing on the move and not paying full attention to where they were going, but I have never seen them bump into the sides of the tank when snoozing, so they normally seem to have an idea of where they are. A lot of research has been done on sleep in humans, and many mysteries still surround sleep and its importance to healthy living, but conducting similar research on sharks is almost impossible for practical reasons, we have a lot to learn about sleep and its purpose in fish and other animals.

[The Silence and I]

The thing is that if dolphins didn't do this, they would drown. The fact that amongst mammals only ceteceans do this indicates that, at least for mammals, there is some inherent disadvantage to this mechanism. The fact that it could have evolved in other mammals but didn't, even fully aquatic ones like sea otters, indicates that there is some selective disadvantage that prevents it from becoming established in other mammals that don't absolutely require it.

Or that there is no specific advantage. The ability to function round the clock is only helpful if you can effectively be active at night and at day--and those require two sets of adaptations generally speaking. If you can't see well at night then you may as well hide somewhere and conserve energy while sleeping instead of wasting energy trying to hunt when conditions are bad, and exposing yourself to predators to boot.

[TheBlackCat]

Or that there is no specific advantage. The ability to function round the clock is only helpful if you can effectively be active at night and at day--and those require two sets of adaptations generally speaking. If you can't see well at night then you may as well hide somewhere and conserve energy while sleeping instead of wasting energy trying to hunt when conditions are bad, and exposing yourself to predators to boot.

What about subterranean species like moles? There is definitely a selective advantage to remaining active all the time, and daylight is meaningless underground.

[The Silence and I]

I don't know for sure, but I suspect they sleep much less than we do, and there isn't a strong driving force (like, say, avoiding drowning) for this to occur. It might help them, but the thing with evolution is that it isn't guided--better systems may be devised, but that doesn't mean another won't do.

It is also a fairly big step to make--you don't just stumble onto the stay awake 24-7 gene in one go, so we are unlikely to see moles develop this. As for whales, it may have been one of these unlikely series of jumps that let them fill the roll they have today instead of the other way around.

[Admiral Valdemar]

I had a graph somewhere that showed the sleeping patterns of a group of animals compared to humans which detailed the sporadic nature of the whole concept with no clearly visible pattern. I'll see if I can dig it up. From memory, I seem to recall it had specs for REM, deep sleep and total sleep which were values that fluctuated again with no clear pattern, though I'm sure every organism required more deep sleep after REM.

[Lord of the Abyss]

I read a long time ago that they did experiments on rats or mice where they forced them to stay awake until they eventually died of sleep deprivation.

Destroy the area of the brain that activates sleep, and they burn out. It takes a few months to kill humans that way, such as with Fatal Familial Insomnia ( a prion disease )