Sleep and Memory Consolidation

Cressalynne M. Ligo
Recently, Dr. Ken Paller came to talk about how learning and memory can work together through Targeted Memory Reactivation (TMR). In order to test whether TMR had an effect on subjects, researchers asked participants to learn how to play two different melodies and then they were prompted to sleep. Once the participants were deep into their sleep, the researchers played one of the melodies for one group of participants. This auditory stimulus was kept a low level as to not disturb the participant. The other group was given no melodies in their sleep. The results of this experiment supported the correlation between learning and sleeping. Researchers found that people who had the melody played while they were sleeping shown significantly higher memory consolidation than those who did not have a melody play during their sleep.

            In a similar study, Borragàn et. al. tested sleep and memory consolidation based on two different sequences.  Unlike Dr. Paller who used auditory stimulants, Borragàn and his colleagues used visuo-motor stimulants. In order to test their hypothesis, researchers asked participants to learn Sequence A on one day and then they were split up into two groups. One of the two groups were allowed to have a regular night of sleep while the other group was deprived of sleep. After a couple days, participants were asked to learn a novel, also known as Sequence B. The results of this study were not significant enough to determine whether the sequential components of visuo-motor had any effect on memory consolidation. However, the researchers did find that sleep helps the memory consolidation of motor skill learning.

            Both of these studies highlight the idea that memory consolidation can be retained through stimulants given before, during, and after sleep. In the study done by Dr. Paller, it was discovered that sleep does have an effect on memory based on how well participants were able to identify sounds. In the other study, researchers were able to conclude that post-training sleep effects motor but not the components in visuo-motor sequence learning. The second study discussed here did not fully support the hypothesis, but it still highlighted the idea that sleep has some part in memory consolidation. Both of these studies work towards attempting to explain how the brain can retain information for a length of time. It also highlights the idea that the brain can memorize sounds, shapes, motor skills, etc. This can help other scientists understand what else can contribute to a person’s memory as well as further improve any research being done on sleep or memory.

LINK: https://www-sciencedirect-com.flagship.luc.edu/science/article/pii/S0278262615000123