In a study of healthy volunteers, researchers at the National Institutes of Health mapped the brain activity that flows when we learn a new skill, such as playing a new song on the piano, and found why taking short breaks practice is the key to learning.
The researchers found that, during rest, the volunteers' brains quickly and repeatedly reproduced faster versions of the activity seen as they practiced typing a code. The more a volunteer repeated the activity, the better he performed during subsequent practice sessions, suggesting strengthened memories of rest.
“Our results support the idea that watchful rest plays as important a role as practice in learning a new skill. It seems to be the period when our brains compress and consolidate memories of what we've just practiced,” said Leonardo G. Cohen, MD, senior researcher at NIH's National Institute of Neurological Disorders and Stroke (NINDS) and senior author of the study published in Cell Reports
“Understanding this role of neural reproduction can not only help shape how we learn new skills, but also how we help patients regain skills lost after neurological injury such as stroke.
The study was conducted at the NIH Clinical Center. Dr. Cohen's team used a highly sensitive scanning technique, called magnetoencephalography, to record the brain waves of 33 healthy, right-handed volunteers as they learned to enter a five-digit test code with their left hand. Participants sat in a chair and under the scanner's long cone-shaped lid.
An experiment began when a subject saw the code “41234” on a screen and asked to type it in as many times as possible for 10 seconds and then take a 10-second break. Subjects were asked to repeat this cycle of alternating practice and rest sessions a total of 35 times.
During the first few attempts, the speed with which the subjects correctly typed the code improved dramatically and then stabilized around the 11th cycle. In an earlier study, led by former NIH postdoctoral fellow Marlene Bönstrup, MD, Dr. Cohen's team showed that most of these gains happened during short rests, not when subjects were typing.
Furthermore, the gains were greater than those obtained after a night's sleep and were correlated with a decrease in the size of brain waves, called beta rhythms. In this new report, researchers looked for something different in individuals' brain waves.
“We wanted to explore the mechanisms behind the memory enhancement seen during waking rest. Several forms of memory appear to depend on repetition of neural activity, so we decided to test this idea for learning procedural skills,” said Ethan R. Buch, Ph.D., Dr. Cohen's team scientist and study leader.
To do this, Leonardo Claudino, Ph.D., a former postdoctoral fellow in Dr. Cohen's laboratory, helped Dr. Buch develop a computer program that allowed the team to decipher the brainwave activity associated with typing. each number in the test code.
The program helped them discover that a much faster version – about 20 times faster – of the brain activity seen during typing was reproduced during rest periods. Over the first eleven practical trials, these compressed versions of the activity were repeated many times – about 25 times – per rest period. This was two to three times more frequent than the activity observed during later rest periods or after the end of the experiments.
Interestingly, they found that repetition frequency during rest predicted memory strengthening. In other words, individuals whose brains repeated the typing activity more often showed greater jumps in performance after each attempt than those who repeated it less often.
"During the early part of the learning curve, we saw that repetition of waking rest was reduced in time, was frequent, and a good indicator of variability in learning a new skill among individuals," said Dr. Buch.
"This suggests that, during waking rest, the brain gathers the memories necessary to learn a new skill."
As expected, the team found that repetition activity used to take place in the sensorimotor regions of the brain, which are responsible for controlling movement. However, they also saw activity in other regions of the brain, namely the hippocampus and the entorhinal cortex.
“We were a little surprised with these latest results.
Traditionally, it was thought that the hippocampus and entorhinal cortex may not play such a substantive role in procedural memory. In contrast, our results suggest that these regions are rapidly vibrating with the sensorimotor cortex when learning these types of skills,” said Dr. Cohen.
“Overall, our results support the idea that manipulating repetition activity during awake rest can be a powerful tool that researchers can use to help individuals learn new skills more quickly and possibly facilitate stroke rehabilitation. .”