Image source: http://nbmpub.com/blog/2013/08/07/bits-of-brain/
It has been well-documented that sleep deprivation negatively impacts cognitive performance, ability to focus, memory consolidation, and muscle generation. Everyone knows that not getting enough sleep is bad for you, but what might actually be causing this impairment on cognition?
Part of the answer might be a recently discovered phenomenon called “local sleep”, where the brain activity in a subset of neurons in an awake organism resembles that of sleep. Researchers looking at neuronal firing properties during awake states found that local groups of neurons in sleep-deprived awake rats can briefly go “offline”. They characterized these offline periods by looking at EEG recordings, which measure electrical brain activity and are often used to study sleep. The EEG recordings of these neuronal groups were similar to those of non-REM sleep, yet the animals were conscious and freely moving (aka clearly not asleep!).
It is important to note that these temporarily offline neurons are not limited to a specific brain area, but rather are from various areas throughout the brain. Furthermore, within one area, some neurons may be offline and others may not. It is also important to note that these episodes of “local sleep” are different than the more well-known “microsleep” episodes. Local sleep occurs while the organism is conscious and functioning, whereas microsleep is characterized by brief lapses of consciousness.
Thus, when you are sleep-deprived, parts of your brain may be sleeping! This is crazy to think about and could be a reason why you experience decreased focus, attention, and performance when you are tired – because, literally, that part of your brain that you are trying to use may be momentarily asleep…
Source: Vyazovskiy et al. (2011). “Local sleep in awake rats.” Nature 472 (7344): 443–447.
At The Synapse 