forming memories Archives - Amazing Health Advances

Pupil Size in Sleep Reveals How Memories are Sorted, Preserved

The AHA! Team — Fri, 28 Feb 2025 06:29:41 +0000

Cornell University via EurekAlert! – Cornell University researchers have found the pupil is key to understanding how, and when, the brain forms strong, long-lasting memories. By studying mice equipped with brain electrodes and tiny eye-tracking cameras, the researchers determined that new memories are being replayed and consolidated when the pupil is contracted during a substage of non-REM sleep. When the pupil is dilated, the process repeats for older memories. The brain’s ability to separate these two substages of sleep with a previously unknown micro-structure is what prevents “catastrophic forgetting” in which the consolidation of one memory wipes out another one. The findings could lead to better memory enhancement techniques for humans and may help computer scientists train artificial neural networks to be more efficient. The study, under embargo until 11am ET on Jan. 1 in Nature, was led by assistant professors Azahara Oliva and Antonio Fernandez-Ruiz. Over the course of a month, a group of mice was taught a variety of tasks, such as collecting water or cookie rewards in a maze. Then the mice were outfitted with brain electrodes and tiny spy cameras that hung in front of their eyes to track their pupil dynamics. One day, the mice learned a new task and when they fell asleep, the electrodes captured their neural activity, and the cameras recorded the changes to their pupils. “Non-REM sleep is when the actual memory consolidation happens, and these moments are very, very short periods of time undetectable by humans, like 100 milliseconds,” Oliva said. Non-REM sleep is when the actual memory consolidation happens “How does the brain distribute these screenings of memory that are very fast and very short throughout the overall night? And how does that separate the new knowledge coming in, in a way that it doesn’t interfere with old knowledge that we already have in our minds?” The recordings showed that the temporal structure of sleeping mice is more varied, and more akin to the sleep stages in humans, than previously thought. By interrupting the mice’s sleep at different moments and later testing how well they recalled their learned tasks, the researchers were able to parse the processes. When a mouse enters a substage of non-REM sleep, its pupil shrinks, and it’s here the recently learned tasks – i.e., the new memories – are being reactivated and consolidated while previous knowledge is not. Conversely, older memories are replayed and integrated when the pupil is dilated. “It’s like new learning, old knowledge, new learning, old knowledge, and that is fluctuating slowly throughout the sleep,” Oliva said. “We are proposing that the brain has this intermediate timescale that separates the new learning from the old knowledge.” The research was supported by the National Institutes of Health, the Sloan Foundation, the Whitehall Foundation, the Klingenstein-Simons Fellowship Program, and the Klarman Fellowships Program. Journal Nature Article Title Sleep micro-structure organizes memory replay To read the original article click here.

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Remembering Faces and Names Can Be Improved During Sleep

AHA Publisher — Thu, 13 Jan 2022 08:00:22 +0000

Northwestern University via Newswise – EVANSTON, Ill. — For those who rarely forget a face, but struggle with names, the remedy for boosting learning may as near as your pillow. New research by Northwestern University is the first to document the effect reactivating memory during sleep has on face-name learning. The researchers found that people’s name recall improved significantly when memories of newly learned face-name associations were reactivated while they were napping. Key to this improvement was uninterrupted deep sleep. “It’s a new and exciting finding about sleep, because it tells us that the way information is reactivated during sleep to improve memory storage is linked with high-quality sleep,” said lead author Nathan Whitmore, a Ph.D. candidate in the Interdepartmental Neuroscience Program at Northwestern. The paper, “Targeted memory reactivation of face-name learning depends on ample and undisturbed slow-wave sleep,” will publish Jan. 12 in the Nature partner journal “NPJ: Science of Learning.” The paper’s senior author is Ken Paller, professor of psychology and director of the Cognitive Neuroscience Program at Weinberg College of Arts and Sciences at Northwestern. The paper was also co-authored by Adrianna Bassard, Ph.D. candidate in psychology at Northwestern. The research team found that for study participants with EEG measures (a recording of electrical activity of the brain picked up by electrodes on the scalp) that indicated disrupted sleep, the memory reactivation didn’t help and may even be detrimental. But in those with uninterrupted sleep during the specific times of sound presentations, the reactivation led to a relative improvement averaging just over 1.5 more names recalled. The study was conducted on 24 participants, aged 18-31 years old, who were asked to memorize the faces and names of 40 pupils from a hypothetical Latin American history class and another 40 from a Japanese history class. When each face was shown again, they were asked to produce the name that went with it. After the learning exercise, participants took a nap while the researchers carefully monitored brain activity using EEG measurements. When participants reached the N3 “deep sleep” state, some of the names were softly played on a speaker with music that was associated with one of the classes. When participants woke up, they were retested on recognizing the faces and recalling the name that went with each face. The researchers say the finding on the relationship between sleep disruption and memory accuracy is noteworthy for several reasons. “We already know that some sleep disorders like apnea can impair memory,” said Whitmore. “Our research suggests a potential explanation for this — frequent sleep interruptions at night might be degrading memory.” The lab is in the midst of a follow-up study to reactivate memories and deliberately disrupt sleep in order to learn more about the relevant brain mechanisms. “This new line of research will let us address many interesting questions — like whether sleep disruption is always harmful or whether it could be used to weaken unwanted memories,” said Paller, who also holds the James Padilla Chair in Arts & Sciences at Northwestern. “At any rate, we are increasingly finding good reasons to value high-quality sleep.” To read the original article click here.

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Saturated Fatty Acid Levels Increase When Making Memories

AHA Publisher — Tue, 06 Jul 2021 07:00:02 +0000

University of Queensland via EurekAlert – Saturated fatty acid levels unexpectedly rise in the brain during memory formation, according to research, opening a new avenue of investigation into how memories are made. Dr Tristan Wallis, from Professor Frederic Meunier’s laboratory at UQ’s Queensland Brain Institute (QBI), said traditionally, polyunsaturated fatty acids were considered important to health and memory, but this study highlighted the unexpected role of saturated fatty acids. “We tested the most common fatty acids to see how their levels changed as new memories were formed in the brain,” Dr Wallis said. “Unexpectedly, the changes of saturated fat levels in the brain cells were the most marked, especially that of myristic acid, which is found in coconut oil and butter. “In the kitchen, saturated fats are those which are solid at room temperature while unsaturated fats are normally liquid. “The brain is the fattiest organ in the body, being 60 per cent fat, which provides energy, structure and assists in passing messages between brain cells. “Fatty acids are the building blocks of lipids or fats and are vital for communication between nerve cells, because they help synaptic vesicles — microscopic sacs containing neurotransmitters–to fuse with the cell membrane and pass messages between the cells. “We have previously shown that when brain cells communicate with each other in a dish, the levels of saturated fatty acids increase.” Researchers have found that fatty acid levels in the rat brain, particularly saturated fatty acids, increase as memories are formed, but when they used a drug to block learning and memory formation in rats, the fatty acid levels did not change. The highest concentration of saturated fatty acids was found in the amygdala — the part of the brain involved in forming new memories specifically related to fear and strong emotions. Study contributor and QBI Director Professor Pankaj Sah said the work opened a new avenue on how memory was formed. “This research has huge implications on our understanding of synaptic plasticity — the change that occurs at the junctions between neurons that allow them to communicate, learn and build memories,” Professor Sah said. To read the original article click here.

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