Our incredible powers of learning are such a crucial part of being human, but we still do not fully understand how our brains absorb new skills.
Powerful modern imaging techniques that allow us to take a closer look at how memory consolidation works have just highlighted the importance of awake rest in the learning process.
Researchers have been aware since 1885 that resting between practices increases memory as they learn new skills. Now, researchers have witnessed our brains quickly reproducing new memories during such relaxing breaks when we perform a new activity, and the repetitions happen up to 20 times faster than the physical act of practicing the activity.
“This is the first demonstration of vigilant neural repetition of a newly trained skill evoked by practice in humans,”
We have known for some time how sleep plays a critical role in the physiology of memory consolidation, stabilization (or possibly switching between) a memory as it moves from short-term to long-term storage.
In the new study, the researchers saw how awake rest can do this for motor memory, where memory consolidation can be significantly more powerful than the same process of sleep.
NINDS neuroscientist Ethan R. Buch, Cohen, and their colleagues put 30 volunteers to the test. The volunteers wrote “41324” with their non-dominant hand as quickly and accurately as possible during 10 second attempts.
Each experiment was followed by a rest period of 10 seconds and repeated 36 times while being recorded by magnetoencephalography (MEG).
This imaging technique measures the magnetic fields generated by the electric currents of our brain cells, giving researchers a very high-resolution glimpse of brain activity.
The decay of magnetic fields in our brain tissue is much steeper than for electric fields, allowing us to distinguish much finer details than other techniques such as electroencephalography.
The researchers observed that more frequent repetitions (as short as 50 ms) during rest periods adapted to better learned skills. This is too fast to be a form of conscious mental repetition, the team explains.
The repetitions occurred more frequently in the first 11 trials (up to 30 times during 10 seconds of rest), which was the steepest part of the learning curve.
“Our data indicate that frequent, rapid awakening reinforces hippocampus and neocortical associations learned from previous practice,” Buch explained, “a process relevant to improving subsequent performance and awake consolidation of skills.”
The team believes that our brains are pushing for replay on the activity they have just recorded is what recruits brain networks involved in processing and storing these skills. They found that this involved our hippocampal, sensorimotor and entorhinal parts of the brain.
“The strong involvement of the hippocampus and medio-temporal activity in repetition of a procedural motor memory was surprising, as this type of memory is often considered not to require contributions from the hippocampus,” Buch said.
Buch and the team warn that they have not yet determined that this is what makes it a skill to play memory.
Interpretations of the MEG recordings are not always accurate, which may affect the strength of their analysis, so further studies are required to confirm their results. However, similar findings have also been observed in mice.
Understanding how our brains take what we practice and turn it into a skill can enable us to optimize learning strategies, including creating more effective therapies for people with brain injuries.
This research was published in Cell reports.