Researchers from the University of Geneva found that giving rewards and enhancing new learnings by taking daytime naps after study periods may help boost children's memory.

In a new study, experts discovered that memories linked to a reward are conversely built up during sleep. Hence, even a short daytime nap may have helpful effects.

The study involved 31 healthy individuals, who were randomly assigned to either a "sleep group" or a "wake group." The researchers evaluated the sensitivity of each group as equal. The participants underwent magnetic resonance imaging (MRI) while they were being taught to remember pairs of images. In total, eight pairs of pictures were shown. The study subjects were told that recalling pairs in four of the set would have a corresponding higher reward.

The participants were then asked to either sleep or rest for 90 minutes. After the said break, the memory test involving the shown pairs of pictures were conducted. The participants were also asked to rate their confidence level in giving out the correct answers. They were also instructed to join a surprise examination that involves the exact test mechanisms three months after.

The findings of the experiment showed that the performance of both groups were better if the picture pairs were associated with higher rewards; nonetheless, the "sleep group" generally fared better.

During the surprise test, subjects who were able to sleep after the learning period had discerningly better test outcomes for the greatly compensated pairs. As for the confidence level, the participants who were able to sleep exuded more self-belief that they can answer the questions correctly, even after three months.

The MRI images showed that those who slept had higher activity in the hippocampus, which is a part of the brain that is vital in creating memories. Three months into the experiments, the sleep group also manifested increased connections between the hippocampus, striatum and medial prefrontal cortex, which are all critical in consolidating memory and processing rewards.

Dr. Kinga Igloi, the lead author of the study said that it is a given that sleep enhances memory but now we also know that it can also aid individuals to choose and keep those that are linked to high rewards.

Igloi further explained that reward may serve as a seal in the brain that traps the learned information. While sleeping, that information is positively formed over information that is linked with low rewards, and is subsequently transported to the long-term memory.

Igloi said that their study is valuable in comprehending the negative effects of lack of sleep on achievement. "It makes adaptive sense that the consolidation of memory should work to prioritise information that is critical to our success and survival," she closed.

The study was published in the journal eLife on Friday, Oct. 16.

Photo: Kourtlyn Lott | Flickr

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