Our incredible learning powers are such a crucial part of being human, but we still don’t fully understand how our brains learn 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 resting in the learning process.
Researchers have been aware since 1885 that rest between practices improves memorization when learning new skills. Scientists have now witnessed that our brains quickly reproduce new memories during such quiet pauses when we perform a new activity, and repetitions occur up to 20 times faster than the physical act of exercising that activity.
“This is the first demonstration of neurological reproduction of a newly developed skill caused by human practice,”
We have known for some time how sleep plays a critical role in the physiology of memory consolidation, stabilizing (or possibly switching between) memory as it moves from short-term to long-term storage.
In the new study, researchers looked at how restful rest can do this for motor memory, where memory consolidation can be significantly more powerful than the same process in sleep.
NINDS neurologist Ethan R. Buch, Cohen and their colleagues tested 30 volunteers. The volunteers dialed 41324 with their non-dominant hand as quickly and accurately as possible in 10-second attempts.
Each test was followed by a 10-second rest period and repeated 36 times until recorded by magnetic encephalography (MEG).
This imaging technique measures the magnetic fields generated by the electric currents of our brain cells, giving researchers a very high-resolution view of brain activity.
The decay of magnetic fields in our brain tissues is much steeper than in electric fields, which allows us to distinguish much finer details from other techniques such as electroencephalography.
The researchers note that more frequent repetitions (shorter than 50 ms) during rest periods are in line with better acquired skills. This is too fast to be a form of conscious mental rehearsal, the team explains.
Repetitions occurred more frequently in the first 11 trials (up to 30 times during a 10-second break), which was the steepest part of the training curve.
“Our data show that frequent, fast-waking repetitions reinforce the hippocampus and neocortical associations learned during previous practice,” explained Buch, “a process important for improving subsequent performance and vigilantly strengthening skills.”
The team believes that our brains are pushing for a repeat of the activity they have just recorded, which is what the brain networks involved in processing and storing these skills are gaining. They found that this included our hippocampal, sensorimotor and entorhinal brains.
“The strong involvement of hippocampal and mid-time activity in replaying procedural motor memory was surprising, given that this type of memory is often considered to require no hippocampal contribution,” Buch said.
Buch and the team warn that they have yet to establish that replaying memory itself is the reason it becomes a skill.
Interpretations of MEG records are not always accurate, which may affect the strength of their analysis, so further research is needed to confirm their findings. But similar findings have been observed in mice.
Understanding how our brain accepts what we practice and turns it into a skill can allow us to optimize learning strategies, including creating more effective therapies for people with brain injuries.
This study was published in Cellular reports.