Taking sleeping pills could help a person improve his memory, a controversial new study has claimed.
Researchers have confirmed the mechanism that enables the brain to consolidate memory and found that a commonly prescribed sleep aid enhances the process.
The discovery could lead to new sleep therapies that will improve memory for ageing adults and those with dementia, Alzheimer's and schizophrenia.
Earlier research found a correlation between sleep spindles - bursts of brain activity that last for a second or less during a specific stage of sleep - and consolidation of memories that depend on the hippocampus.
The hippocampus, part of the cerebral cortex, is important in the consolidation of information from short-term to long-term memory, and spatial navigation. The hippocampus is one of the first regions of the brain damaged by Alzheimer's.
Sara C Mednick from the University of California Riverside and her team demonstrated, for the first time, the critical role that sleep spindles play in consolidating memory in the hippocampus, and they showed that pharmaceuticals could significantly improve that process, far more than sleep alone.
"We found that a very common sleep drug can be used to increase verbal memory," said Mednick, the lead author of the study.
"This is the first study to show you can manipulate sleep to improve memory. It suggests sleep drugs could be a powerful tool to tailor sleep to particular memory disorders," Mednick said in a statement.
A total of 49 men and women between the ages of 18 and 39 who were normal sleepers were given varying doses of zolpidem (Ambien) or sodium oxybate (Xyrem), and a placebo, allowing several days between doses to allow the pharmaceuticals to leave their bodies.
Researchers monitored their sleep, measured sleepiness and mood after napping, and used several tests to evaluate their memory.
They found that zolpidem significantly increased the density of sleep spindles and improved verbal memory consolidation.
"(P)harmacologically enhancing sleep spindles in healthy adults produces exceptional memory performance beyond that seen with sleep alone or sleep with the comparison drug (sodium oxybate)," the researchers said.
Individuals with Alzheimer's, dementia and schizophrenia also experience decreases in sleep spindles, according to the study published in the Journal of Neuroscience.