Reportedly for the first time, scientists have found a link between brain deterioration, poor sleep and memory loss as we grow older, according to the University of California, Berkeley.
In a press release, UC Berkeley is claiming that this research “opens the door to boosting the quality of sleep in elderly people to improve memory.”
UC Berkeley neuroscientists have discovered that the slow brain waves generated during “the deep, restorative sleep we typically experience in youth play a key role in transporting memories from the hippocampus – which provides short-term storage for memories – to the prefrontal cortex’s longer term ‘hard drive,’” according to the release.
But there is a problem with older people. Scientists believe that their “memories may be getting stuck in the hippocampus due to the poor quality of deep ‘slow wave’ sleep, and are then overwritten by new memories,” UC Berkeley said.
“What we have discovered is a dysfunctional pathway that helps explain the relationship between brain deterioration, sleep disruption and memory loss as we get older – and with that, a potentially new treatment avenue,” sleep researcher Matthew Walker, an associate professor of psychology and neuroscience at UC Berkeley, said in a statement.
He is senior author of the study published last Sunday in the journal Nature Neuroscience.
This research helps explain why the elderly experience forgetfulness, such as not recalling people’s names, according to UC Berkeley.
“When we are young, we have deep sleep that helps the brain store and retain new facts and information,” Walker said. “But as we get older, the quality of our sleep deteriorates and prevents those memories from being saved by the brain at night.”
Healthy adults spend one-quarter of the night in deep, non-rapid-eye-movement (REM) sleep.
“Slow waves are generated by the brain’s middle frontal lobe,” the university’s press release said. “Deterioration of this frontal region of the brain in elderly people is linked to their failure to generate deep sleep, the study found.”
Learning that slow waves in the frontal brain help strengthen memories is a start for devising treatments for memory loss in the elderly, such as transcranial direct current stimulation or pharmaceutical remedies, according to the university.
It cited an earlier study where German neuroscientists used electrical stimulation of the brain in young adults to enhance deep sleep and doubled their overnight memory. UC Berkeley researchers plan to conduct a similar sleep-enhancing study in older adults to see if it will improve their overnight memory.
“Can you jump start slow wave sleep and help people remember their lives and memories better? It’s an exciting possibility,” Bryce Mander, a UC Berkeley psychology postdoctoral fellow and lead author of the latest study.
For the UC Berkeley study, researchers tested the memory of 18 healthy young adults (mostly in their 20s) and 15 healthy older adults (mostly in their 70s) after a full night’s sleep. Before going to sleep, participants learned and were tested on 120 word sets that taxed their memories.
As they slumbered, an electroencephalographic (EEG) machine measured the subjects’ brain-wave activity. They were later tested again on the word pairs, while being given functional and structural Magnetic Resonance Imaging (fMRI) scans.
“In older adults, the results showed a clear link between the degree of brain deterioration in the middle frontal lobe and the severity of impaired ‘slow wave activity’ during sleep,” the press release said. “On average, the quality of their deep sleep was 75 percent lower than that of the younger participants, and their memory of the word pairs the next day was 55 percent worse.”
But in younger adults, “brain scans showed that deep sleep had efficiently helped to shift their memories from the short-term storage of the hippocampus to the long-term storage of the prefrontal cortex,” according to the release.
The research was funded by the National Institute of Aging of the National Institutes of Health.