Neuron: Nerve cells in adult mice enhance memory while they sleep.

, June 24, 2020 /PRNewswire/
Biovalley --A study published June 4 in the journal Neuron found that in the hippocampus of adult mice's brains, newly formed cells reactivate during the rapid eye movement (REM) phase of sleep after learning experience"It's a very cool paper," said Sheena Josselyn, a neuroscientist at the University of Toronto,This is the first study to link newborn neurons to sleep-dependent memory consolidationI believe this will have a wide-ranging impact on scientists who study memory, sleep, and those interested in adult neurogenesisJosselyn was not involved in the studymost cells in the brains of adult mammals do not replicateBut deep in the middle of this organ, in a special area of the hippocampus called toothed return, new neurons continue to grow at a slow rate throughout an animal's lifeIn other cognitive tasks, neurogenesis is thought to be important for memory formationIn fact, if the activity of neurons (ABNs) in adult mice is disturbed in the learning experience, animals will not be able to remember events as effectively as they do when these cells are alonepicture source: thescientist
however, learning is only part of the memory formationTo maintain memory, sleep, especially fast eye movement sleep, is essential"Sleep deprivation usually reduces neurorenewal," said Masanori Sakaguchi, a neuroscientist at the International Institute of Integrated Sleep Medicine at Tsukuba University in JapanThe question, Sakaguchi says, is, "What do adult-born neurons do in sleep?" "
to find out, Sakaguchi's team first tested nerve activity in mice after learning experiences and subsequent sleep During the learning experience, the mice's feet were clicked when they entered a specific cage Using micromicroscopes and fluorescent markers attached to the skulls of free-moving mice to track ABN activity, the team found that ABNs, activated after a contextual shock learning event, were more likely to be reactivated during the animal's next REM sleep phase fast eye movement sleep, which lasts only about a minute in mice when humans dream, can be determined by electrophysiological and muscle tone measurements Although it is not known whether the mice will dream, the reactivation of this learning-related ABN suggests that this activity may be part of memory playback next, the team used the light gene to stimulate or inhibit ABN activity in the brains of mice that experienced electric shocks while they slept They showed that during fast eye-movement sleep, ABN regulation allowed the animals to forget their fears -- when they returned to the cages associated with electric shocks, they were less frozen than those with UNdisturbed mice The brain wave patterns in animals sleeping are not in themselves affected by the of photo
gene therapy, suggesting that memory impairment is not just the result of sleep disruption the extent of memory damage is similar whether ABNs are stimulated or suppressed Gyorgy Buzsaki, a neuroscientist at New York University School of Medicine who was not involved in the study, said it was because both caused interference with these neurons in fact, previous research by Rene Hen of Columbia University and his colleagues also showed that the stimulation or inhibition of light genes during learning can damage the memory of mice "Obviously, ABNs play a role in memory formation," said Hen, who wasn't a member of the study team, "but this is really the first time someone has suggested their role in rapid eye movement sleep." "
photo source: COURTESY OF MASANORI SAKAGUCHI
Sakaguchi and his colleagues' next plan is to illustrate how ABNs integrate into existing memory pathways when coding new memories so that this knowledge can be "applied to the development of new treatments for memory disorders." assuming that these findings can be confirmed, and that they can be extended to other types of memories -- not just fear-conditional reflexes -- "I believe that they also apply to humans," Buzsaki said He said the hippocampus and toothed back were, after all, "very old structures" and that many of their mechanisms were well preserved (BioValleyBioon.com) References: Adult-Born Neurons SMog Memories While Mice Sleep
What Do News in the Brains of Adults Actually Do? Kumar et al., "Sparse Activity of hippocampal adult-born neurons ys sm rem sleep is ," "neuron, doi: 10.1016/j.neuron.2020.05.008, 2020.
Distinct Contribution of Adult-Born Hippocampal Granule Cells to The .