New Study Reveals Some Synapses Shrink by a Considerable Amount During Sleep

In order to understand better the benefits of sleep, two teams of researchers analyzed the effects of snoozing on the synapses. During waking hours, the brain assimilates every new experience and learns new things by the hour. Hence, strong connections between neurons are formed, dubbed synapses. Either storing memories, learning new information, or acquiring new skills, synapses work by constantly strengthening the bond between neurons, ultimately changing the structure of the brain altogether, in order to adapt.

However, investing into endless learning takes its toll on the human brain, as a lot of energy is needed to maintain the connections between neurons up and running. Since humans do not possess an endless source of energy, synapses cannot be strengthened indefinitely. Even if humans would have the energy required to keep strengthening these bonds forever, scientists say that eventually, our brains would go into a state of overdrive, which would ultimately result in epilepsy or constant seizures.

Johns Hopkins University’s Richard Huganir says that if synapses would complete their strengthening process, neurons would no longer be able to encode any more information. However, the human body comes with an emergency safety switch that prevents the brain from overloading: sleep.

Researchers have discovered that not only does some synapses get stronger during sleep, but some could be completely erased, or at least, shrunk by up to 20 percent. The scientists say the human brain evolved this way in order to get rid of unnecessary detail over time and store only vital information.

At this point, however, these are mere speculations. The researchers discovered that while some synapses undergo the shrinking process, if one was stronger than another, they would both be reduced to smaller scales, but still keep their status. At the same time, however, some synapses are spared and go completely unchanged during sleep. The scientists believe these are the regions of the brain where synapses that have been formed long ago were formed and could be the repositories of very strong memories, such as the name of your mother, highly unlikely to forget, even in a state of sleep deprivation.

On the other hand, the scientists believe insignificant details such as newly acquired memories that do not serve an important purpose are deleted after a few days.

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