Researchers also say they managed to improve memory consolidation by utilizing deep-brain stimulation during sleep.
By Pesach Benson, TPS
Scientists in Tel Aviv and California say they have uncovered how the human brain strengthens memories during sleep, offering hope to individuals suffering from various forms of memory impairment, such as dementia.
The study found that the brain consolidates memories during sleep through coordination between the hippocampus and frontal cortex. Moreover, the researchers say they managed to improve memory consolidation by utilizing deep-brain stimulation during sleep.
The research was led by Israeli Dr. Maya Geva-Sagiv, currently at University California, Davis, in partnership with Professors Yuval Nir of Tel Aviv University and with Itzkak Fried, of both TAU and UCLA. Their findings were published in the peer-reviewed Nature Neuroscience journal on Thursday.
To test their hypothesis, Prof. Fried implanted electrodes in the brains of 18 epilepsy patients, allowing advanced brain stimulation techniques to be integrated into the research. The researchers were able to enhance memory consolidation through a specialized stimulation protocol that improved synchronization between these two brain regions.
The hippocampus is the part of the brain responsible for acquiring new memories, while the frontal cortex is where long-term memories are stored.
By monitoring activity in the hippocampus during sleep, the system enables precisely timed delivery of electrical stimulation to the frontal cortex to improve the brain’s memory consolidation.
Participants underwent two memory tests, comparing their performance after two different nights—one undisturbed and one with deep-brain stimulation. In the morning, they were asked to recognize pictures of famous individuals they had been shown the previous evening. The study demonstrated that deep-brain stimulation significantly enhanced the accuracy of their memory.
The researchers also discovered that the intervention did not significantly increase the number of correct answers from participants but rather reduced the number of incorrect responses. This suggests that sleep sharpens the accuracy of our memory by eliminating distractions from the relevant memory trace.
“We know that a good night’s sleep is crucial for the consolidation of long-lasting memories, but until now, we had limited evidence about the specific processes at work in the human brain during sleep,” Dr. Geva-Sagiv explained.
“In this study, we directly examined the role of neural activity and electrical brain waves during sleep. Our objective was to enhance the natural mechanisms involved and gain a deeper understanding of how sleep aids in stabilizing memories,” she said.