US scientists have linked poor sleep with memory loss and cognitive deterioration as we age, opening the door to therapies for better sleep and recall capacity.
University of California-Berkeley neuroscientists have found that the slow brain waves during the deep, restorative sleep typically experienced in youth play a key role in transferring memories from the hippocampus - the short-term storage for memories - to the prefrontal cortex's longer term hard drive.
"When we are young, we have deep sleep that helps the brain store and retain new facts and information. But as we get older, the quality of our sleep deteriorates and prevents those memories from being saved by the brain at night," says sleep researcher Matthew Walker, associate professor of psychology and neuroscience and study co-author at Berkeley.
"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," adds Walker, the journal Nature Neuroscience reports.
Healthy adults typically 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. Deterioration of this frontal region of the brain in elderly people is linked to their failure to generate deep sleep, the study found, according to a California statement.
The discovery that slow waves in the frontal brain help strengthen memories paves the way for therapeutic treatments for memory loss in the elderly. For example, in an earlier study, neuroscientists in Germany successfully used electrical stimulation of the brain in young adults to enhance deep sleep and doubled their overnight memory.
"Can you jumpstart slow wave sleep and help people remember their lives and memories better? It's an exciting possibility," said Bryce Mander, post-doctoral fellow in psychology at Berkeley, who led the study.