Computational model of brain helps unravel role of sleep in memory formation: Study | The Voice TV

Quote :

ज्ञान ही एकमात्र ऐसा धन है जिसे कोई चुरा नहीं सकता - अज्ञात

Science & Technology

Computational model of brain helps unravel role of sleep in memory formation: Study

Date : 28-Oct-2022

Scientists have unravelled more details about how various stages of sleep help in memory formation and storage, according to a study.

A team of scientists from the University of Pennsylvania has found that as the body moves between rapid-eye movement (REM) and slow-wave sleep cycles, the hippocampus and the neocortex interact in ways that are key to memory formation.

 

 

The hippocampus is the brain's centre for new memories and is tasked with learning the world's day-to-day episodic information while the neocortex is responsible for facets such as language, higher-level cognition and more permanent memory storage.

 

"We have known for a long time that useful learning happens during sleep," said lead researcher Anna Schapiro.

"You encode new experiences while you are awake, you go to sleep, and when you wake up your memory has somehow been transformed," the researcher said.

Yet, precisely how the new experiences get processed during sleep has remained largely a mystery, according to the team.

Using a neural network computational model that the researchers built, they now have new insight into the process.

As the brain cycles through slow-wave and REM sleep, which happens about five times a night, the hippocampus "teaches" the neocortex what it learned, transforming novel, fleeting information into enduring memory, according to the study, which is published in the Proceedings of the National Academy of Sciences (PNAS).

"This is not just a model of learning in local circuits in the brain. It is how one brain region can teach another brain region during sleep, a time when there is no guidance from the external world," Schapiro said.

"It is also a proposal for how we learn gracefully over time as our environment changes," she said.

Schapiro, who studies learning and memory in humans, had long thought that sleep played a part here, something she and her team have been testing in a lab, and recording what happens in the brain as participants sleep.

Her team also builds neural network models to simulate learning and memory functions. For this work specifically, Schapiro and her colleagues built a neural network model composed of a hippocampus and the neocortex.

 

 

During simulated sleep, the researchers can watch and record which simulated neurons fire when in these two areas, then analyse those activity patterns.

 

The team, according to the study, ran several sleep simulations using a brain-inspired learning algorithm it built. The simulations revealed that during slow-wave sleep, the brain mostly revisits recent incidents and data, guided by the hippocampus, and during REM sleep, it mostly reruns what happened previously, guided by memory storage in the neocortical regions.

"As the two brain regions connect during non-REM sleep, that is when the hippocampus is actually teaching the neocortex," Dhairyya Singh, another researcher in Schapiro's lab, said.

"Then, during the REM phase, the neocortex reactivates and can replay what it already knows, solidifying the data's hold in long-term memory," he said, adding that the alternation between the two sleep stages matters too.

"When the neocortex does not have a chance to replay its own information, we see that the information there gets overwritten. We think you need to have alternating REM and non-REM sleep for strong memory formation to occur," Singh said.

The findings are consistent with what is known in the field, though aspects of the model are still theoretical, the team said in a statement.

"We still need to test this," Schapiro said.

"One of our next steps will be to run experiments to understand whether REM sleep is truly bringing up old memories and what implications that might have for integrating new information into your existing knowledge," she said.

Because the current simulations were based on a typical adult getting a healthy night of sleep, the research findings do not necessarily transfer to other types of adults or less-than-stellar sleep habits, the scientists said.

They also do not offer insight into what is happening with children, who require different amounts and types of shut-eye than adults.

Schapiro said she sees great potential for her model to answer some of these outstanding questions.

"Having a tool like this allows you to go in many directions, especially because sleep architecture changes across the lifespan and in various disorders, and we can simulate these changes in the model," she said.

 
RELATED POST

Leave a reply
Click to reload image
Click on the image to reload

Advertisement









Advertisement