Stimulating NREM sleep can boost cognitive function, memory

New Delhi: A team of scientists has uncovered a key mechanism by which sleep enhances neuronal and behavioural performance, potentially changing our fundamental understanding of how sleep boosts brainpower.

While it’s well known that sleep enhances cognitive performance, the underlying neural mechanisms, particularly those related to nonrapid eye movement (NREM) sleep, remain largely unexplored.

A new study by a team of researchers at Rice University and Houston Methodist’s Center for Neural Systems Restoration and Weill Cornell Medical College, aimed to uncover this phenomenon.

Published in the journal Science, the research revealed how NREM sleep — the lighter sleep one experiences when taking a nap, for example — fosters brain synchronisation and enhances information encoding, shedding new light on this sleep stage.

The researchers replicated these effects through invasive stimulation, suggesting promising possibilities for future neuro-modulation therapies in humans.

The implications of this discovery potentially pave the way for innovative treatments for sleep disorders and even methods to enhance cognitive and behavioural performance.

“During sleep, we observed an increase in low-frequency delta wave activity and synchronised firing among neurons across different cortical regions,” said Dr Natasha Kharas, a former researcher in Dragoi’s lab and current resident in neurological surgery at Weill Cornell.

“After sleep, however, neuronal activity became more desynchronised compared to before sleep, allowing neurons to fire more independently. This shift led to improved accuracy in information processing and performance in the visual tasks,” Kharas added.

The findings demonstrated that sleep improved the animals’ performance in the visual task with enhanced accuracy in distinguishing rotated images.

Importantly, this improvement was unique to those who actually fell asleep — the macaques that experienced quiet wakefulness without falling asleep did not show the same performance boost.

“This finding is significant because it suggests that some of the restorative and performance-enhancing effects of sleep might be achieved without the need for actual sleep,” said Valentin Dragoi, professor of electrical and computer engineering at Rice.

The idea that NREM sleep effectively “boosts” the brain in this way, and that this resetting can be mimicked artificially, offers potential for developing therapeutic brain stimulation techniques to improve cognitive function and memory.