First, the good news: a University of Ottawa researcher has discovered that younger individuals have the ability to consolidate new memories and skills while they sleep. The bad news? The same study shows that in older adults, age-related changes in sleep may hamper this ability.
In his recent study, Dr. Stuart Fogel explains why older adults are able to learn new motor tasks normally, but do not derive the same benefits from sleep as younger adults do. While we sleep, parts of our brains emit sleep spindles, which are short bursts of electrical activity. The study provides the first evidence that age-related structural differences in the grey matter of the brain, in relation to sleep spindles, may underlie deficits in our ability to consolidate motor skill memories as we age.
As we age, the quality and quantity of our sleep diminishes. Healthy young adults typically spend between 45% and 55% of their sleep time in non-rapid eye movement (REM), stage 2 sleep. However, as we age, the total amount of non-REM sleep drops precipitously. One of the main characteristics of stage 2 sleep is the presence of sleep spindles, which help block noise that disrupts sleep and are related to overnight consolidation of our memories, leading to improved motor skills, reasoning and problem solving.
The study results suggest that with age, the relationship between grey matter and sleep spindles deteriorates, and this may explain why as we get older, we can learn new skills, but do not get the same boost that sleep affords for memory.
SF: “While the body rests during sleep, our brains are very active, transforming and solidifying newly acquired memories into a more permanent and accessible form. Our research has shown that spindles are an important marker for this memory function of sleep. Importantly, a reduction in spindles with age may be an electrophysiological marker for both the functional and structural changes in the parts of the brain that support memory functions.”
Dr. Stuart Fogel is a cognitive neuroscientist at the University of Ottawa and Director of Sleep Neuroscience Research at The Royal's Institute of Mental Health Research who investigates the function of sleep in learning and memory. He was the first to discover that bursts of brain activity during sleep, called “sleep spindles”, are involved in the overnight enhancement of newly formed memories, and are a biological marker of human intelligence. His research employs a unique combination of behavioural, cognitive, electrophysiological, functional and structural neuroimaging; it is one of the few in the world to employ combined EEG-fMRI techniques to explore the function of sleep in memory and cognition.
Dr. Stuart Fogel’s tips for improving sleep and memory
- The brain craves regularity: Go to bed and wake up at the same time every day. Most people need 7-to-8 hours of sleep, but some adults, and especially children, teens and young adults, require more.
- Wind down before bedtime: A combination of dim lighting and relaxing pastimes is best.
- The bedroom is for sleeping: As we age, our brains generate less of the activity that maintains sleep, making our sleep more vulnerable to interruption by outside influences. To make the most of your time in bed, eliminate the light and noise caused by televisions, cell phones, laptops, loud music and the outdoors. Keep your bedroom dark, cool and quiet.
Read the study published in Neurobiology of Aging.
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