Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

Question

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep.I'm interested if human brain has some parts of it that can be asleep while others are awake? In other words, **can a human brain be only partially asleep while experiencing insomnia or similar sleep disturbances?**If human brain can have different parts "sleeping" independently of each other, **is it possible that the times to "fall asleep" vary between these different parts of the brain?**I would appreciate research articles on the topic or just the names of brain regions that may exhibit behavior described above.**Update**: I've taken a look at R&K "principles and practice of sleep medicine"' and it mentions the following parts as involved in sleep:Medulla, preoptic area, hypothalamus, thalamus, entire neocortex involved in NREM.Neurotransmitter systems: histaminergic, orexinergic, serotonergic, noradrinergicSleep factors: adenosine, interleukin-1 and other cytokines, prostaglandin D2, growth hormone releasing hormone, nitric oxide, all promote sleep in or around preoptic area.This makes me hypothesize that drugs that modify the effects of these systems (ex- caffeine affecting adenosine) could result in sleep- related disturbances in these systems, potentially causing them to fall asleep later that usual. But I'm looking for more info to fihre out if this is true

Answer 1

The main problem with this question is the use of the term "sleep", when referring to an organ, such as the brain. The brain itself does not go to sleep, as we know it. There are periods of quiescence, or reduced neural activity, but this shouldn't be referred to as "sleeping". As far as the entire organism (human being in this case) going to "sleep", the process is even more complex than you elude to in your question, with more transmitter systems being involved (such as the cholinergic system, which wasn't mentioned in your synopsis). As for drugs modifying different transmitter systems, this is certainly the case, and different drugs can affect the neural activity of different parts of the brain, and affect different transmitter systems. But again, this is not the same as "sleep", and these drugs don't "put the brain to sleep".