This question was brought to you by,… me wondering if animals even lose consciousness when they sleep, seeing as they are instantly up and moving after the slightest noise.
In: Biology
let’s preface by “I’m not an expert, this is nothing more than an educated guess”. If I’m wrong correct me. I’d be happy to learn more
I’ll go with the definition that “loss of consciousness” mean the loss of conscious actions. You’re alive, your body still works and keep you alive, but you do not take actions other than sustaining your life.
There are multiple reasons to go unconscious. The most common is that for some reason your brain assume it cannot sustain all bodily functions safely. As a result, it chooses what functions get absolute priority and shutdown whatever is not necessary. Sleep is partially this, as in that case, the body can usually maintain for a bit longer, but chooses not to, to allow you to rest, but still be capable to run if the need arise.
If you don’t have enough oxygen, if you don’t have enough energy, the brain can tell you “stop now”.
The difference in our ability on waking up is simply due to our environments. We human have reached a point where our brain associate “sleep” with “safety”. We have created environment sturdy enough that we don’t need to worry when we sleep. Animals don’t. So our brain shut down most of the warnings to save some extra energy and just let us sleep. When we wake up, we’re also still sleepy, as waking up is usually a slow process. Only difference with animal so far is that they don’t shut those extra warnings. “Sleep” is associated with “weakness” and as such, hearing is still a top priority. Noise is thus enough for their brain to start waking up.
For the ability to move instantly, we also have it. Ever had one of those dreams where you fall? Well that’s it. When your brain goes “EMERGENCY” and wakes you up, instead of following the normal waking routine, it start pumping adrenaline and other chemical to allow you to ignore any negative effects. “You’re about to die, wake the fuck up samurai” kind of deal. Basically, instead of saving resources (which is the whole point of sleeping) it goes in overdrive and abuses resources so that it can ignore anything and let you live. It’s also similar to a parent waking immediately if their child cries. Your brain assume that waking up quickly is more valuable than long term rest. This trigger in animal when they hear something that their brain interpret as danger.
Different parts of the brain start firing. The trigger can be a whole number of things: sound, light, feeling, some internal timer. Whatever wakes you. It kicks off some process which causes different parts of the brain to be more active (more neurons firing). The brain isn’t all off while you sleep (otherwise your heart and thyroid would be a mess), but not all parts are on. Conscious thought resides on the outer-layer of the brain away from the brain stem. When they’re active and processing, you’re awake.
> if animals even lose consciousness when they sleep
Yes. Most of them. I think there are exceptions.
> seeing as they are instantly up and moving after the slightest noise.
Some of them are just light sleepers, seeing as there’s risk that they’ll be eaten if they’re not.
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