Why sleep is important for learning and creating long-lasting memories, according to Harvard University

The brainFor many years, it was considered the most mysterious and fascinating organ for scientists. Which is He rules and commands over a living being. However, science has managed to unravel many mechanisms that this “ruler” applies not only to the body, but also to itself. At the moment The first human study, Harvard experts were able to determine the importance of sleep for learning and forming long-term memories.

Animal models are, at first, the best way for scientists to test their theories. In the case of the brain, studies have been done where rats are the hero in giving details about what is being investigated. The next step to confirm the hypotheses will inevitably be studies in humans.

As described by scientists, in their paper published in Journal of Neuroscience, They were able to explain how humans form and learn memories. They also warned that these results in the end They will help develop tools for the care of patients with neurological diseases or injuries.

Tests were conducted in facilities Massachusetts General Hospital (HGM)where local experts worked side by side with scientists from Harvardsubordinate Brown UniversityThe Department of Veterans AffairsAmong other institutions.

The hypothesis which they sought to confirm is called “Repetition“, A phenomenon that occurs during sleep and has been observed in animals for a long timeThe study’s lead author, a neurologist, explained Daniel Rubin From the HGM Center for Neurotechnology and Nerve Recovery. that it The strategy the brain uses to remember new information.

In the animal model, a mouse is trained to discover its own path as it navigates through a maze. This procedure is illustrated by a A specific pattern of brain cells (neurons), which form a kind of lighted pathway as you travel the right path. As Robin explained, “Later, while the animal sleepsyou can watch this These neurons will fire again in the same order.”

According to experts, “This repetition of neuron firing during sleep is the brain’s way of exercising newly acquired information and integrating it into memory, Converting short-term memory to long-term memory”, as stated in the statement from Harvard University. However, they cautioned that this brain behavior has only been confirmed in animals.

“There was an open question in the neuroscience community: How valid is this model of how we learn things in humans? Can it be different for each type of learning?asked neurologist Sidney Cash, co-lead author of the study and co-director of the Center for Neurotechnology and Nerve Recovery at HGM.

In Cash’s words, what they wanted to understand was whether this repetition, which occurs when learning motor skills, could help “Guiding the development of new treatments and tools for people with neurological diseases and injuries”.

To check if repetition occurs in The human motor cortex, which is the area of ​​the brain that controls movementCash, Robin and their co-branded what they called T1136-year-old man Quadriplegia (Quadriplegia)And the Pathology that prevents movement of the upper and lower extremities after spinal cord injury.

as they described, T11 was a volunteer in a clinical trial of a brain-computer interface deviceThis allowed him to use the computer’s cursor and keyboard on one screen. This device was developed by the BrainGate Consortium, a collaborative group of physicians, neuroscientists, and engineers from various institutions, which aims to createTechniques for restoring connectivity, mobility, and independence for people with neurological disease, injury, or limb loss.

It was one of the study activities T11 will perform a memory task similar to the electronic game “Simon”.in which player Notice a pattern of intermittent colored lights, which you should remember later and reproduce. The way the man controlled the path was by thinking about the movement his hand should make.

Using sensors implanted in the motor cortex, The scientists were able to detect patterns of T11 neural activation, which were, as expected, a reflection of his hand movement.. Brain signals were recorded and transmitted wirelessly to a computer. During the night, experts note that this action also occurs while the patient is asleep.

“What we found was absolutely amazing,” Robin said. As he explained, “I was basically playing the game, overnight, in my sleep“. The neural firing patterns occurred several times and matched what was shown during the day, when T11 was playing “Simon”.

Robin stated thatThis is the most direct evidence for replication in the motor cortex ever seen during sleep in humans‘, because most It was repetition during slow wave sleep, which is one of the stages of deep sleep. Whereas when T11 entered ‘REM sleep’, detection of recurrence was less likely. To the study’s lead authors, This work is “a basis for learning more about reproduction and its role in learning and memory in humans.”

“We hope we can harness this information to help build better brain-computer interfaces and create models that help people To learn faster and more efficiently to regain control after an injury,” Cash said, noting the importance of developing this type of research from animals to humans.

Robin is a professor of neuroscience at Harvard Medical School, while Cash is an associate professor of neuroscience at Harvard Medical School.

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