A new study uncovers how NREM sleep synchronizes brain activity, enhancing cognitive performance. This discovery could lead to novel treatments for sleep disorders and methods to boost brainpower.
Researchers from Rice University, Houston Methodist’s Center for Neural Systems Restoration and Weill Cornell Medical College have unveiled a groundbreaking discovery about how nonrapid eye movement (NREM) sleep improves cognitive function. This study, published in the journal Science, sheds light on the essential role NREM sleep plays in brain synchronization and information encoding.
“Our study not only deepens our mechanistic understanding of sleep’s role in cognitive function but also breaks new ground by showing that specific patterns of brain stimulation could substitute for some benefits of sleep.” co-author Valentin Dragoi, a professor of electrical and computer engineering at Rice, Rosemary and Daniel J. Harrison III Presidential Distinguished Chair in Neuroprosthetics at Houston Methodist and professor of neuroscience at Weill Cornell, said in a news release.
The research demonstrates how NREM sleep, commonly experienced during light sleep or naps, enhances neuronal and behavioral performance. This newfound understanding could revolutionize our approach to treating sleep disorders and enhancing cognitive functions.
The team employed advanced multielectrode arrays to monitor the neural activity of macaques engaged in a visual discrimination task. Their findings showed a significant improvement in task performance post-NREM sleep, with animals more accurately distinguishing rotated images.
“During sleep, we observed an increase in low-frequency delta wave activity and synchronized firing among neurons across different cortical regions,” first author Natasha Kharas, a former researcher in Dragoi’s lab and now a current resident in neurological surgery at Weill Cornell, said in the news release. “After sleep, however, neuronal activity became more desynchronized 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.”
Additionally, the study revealed that artificially simulating the neural effects of sleep using low-frequency electrical stimulation of the visual cortex also enhanced task performance. This suggests that cognitive benefits of sleep might be replicated without actual sleep.
“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,” Dragoi added. “The ability to reproduce sleeplike neural desynchronization in an awake state opens new possibilities for enhancing cognitive and perceptual performance in situations where sleep is not feasible — such as for individuals with sleep disorders or in extenuating circumstances such as space exploration.”
The research further explored the phenomenon through a neural network model, showing the weakening of both excitatory and inhibitory brain connections during sleep. This asymmetrical weakening boosts neural excitation, optimizing brain function.
“We have uncovered a surprising solution that the brain employs after sleep whereby neural populations participating in the task reduce their level of synchrony after sleep despite receiving synchronizing inputs during sleep itself,” added Drago.
Ultimately, this study not only elucidates the mechanisms of NREM sleep but also opens avenues for innovative brain stimulation therapies that could enhance cognitive performance independently of sleep.
This research marks a significant step forward in neuroscience, promising future applications in both medical and high-stress environments like space exploration.