Humans have three basic needs to survive: food, oxygen and sleep. Rest is essential for the brain to “organize,” which includes either shedding newly learned information or long-term memory. Interestingly, a new study reveals that this resetting of brain connections only happens during the first half of the night's sleep, StudyFinds reports.
Sleep is essential for health. Photo: pexels (Archive)
Sleep is one of the greatest mysteries of the human body. While we know that sleep is beneficial to health, the reasons behind certain processes remain unknown. The theory of the current study indicates that it is possible that the brain removes certain neural connections during sleep to prevent information overload, making it easier to learn new things the next day.
When a person is awake, the connections between brain cells become stronger. However, making a strong and complex neural connection requires more energy. If any brain connection could be stronger and more complex, then it would become energetically unsustainable. According to the study published in the journal Nature, the brain may have developed this reset mechanism to prevent too many active brain connections from forming, which would leave little energy to create new ones in the future.
“An “off-line” period”
“Although sleep's function remains mysterious, it's possible that it serves as an “off-line” period where these connections can be loosened throughout the brain to prepare us to learn new things the next day.“, says Jason Rihel, Professor in the Department of Cell Biology and Development at University College London.
However, the findings of this research raise questions about why the brain resets neural connections only in the first half of the night and what role the second half of the sleep period plays.
The study was conducted using zebrafish. The study authors recorded the brain activity of the zebrafish both while they were sleeping and while they were not sleeping.
The researchers found that the brain added new connections when awake and lost many of them during the night. However, this depended on the amount of sleep the fish had accumulated during the day before being allowed to rest.
“Sleep has the role of reducing connections in the brain”
Thus, when the scientists deprived the fish of sleep for a few more hours, they observed an increase in brain connections.
“If the patterns we observed are confirmed in humans, our findings suggest that this remodeling of synapses may be less effective during the mid-day siesta, when the need for sleep is still low, rather than at night, when we really need sleep“, adds Dr. Rihel.
The team notes that the reorganization of these connections between brain cells occurred during slow-wave sleep, a part of the sleep cycle that occurs early in the night.
“The findings add to the theory that sleep works to reduce connections in the brain, which means it prepares to learn and make new connections the next day. But our study tells us nothing about what happens in the second half of the night“, says Anya Suppermpool, professor at UCL Cell & Developmental Biology and at the UCL Ear Institute, who was lead author of the study.
Dr. Suppermpool notes that the second half of sleep may have an entirely different purpose. There are some theories that suggest that the second part of sleep is to remove toxins and dead cells. In addition, another theory concerned the connection between sleep and the repair of damaged cells.
