Researchers have shown that stimulating specific brain activity in awake mice produces some of the restorative effects of deep sleep, including improved memory. The team now plans to explore whether a similar approach could work in people.
In the study, scientists at the University of Wisconsin-Madison genetically engineered mice so that neuronal activity in one half of the brain could be controlled with light. They kept the animals awake for five hours while exploring new objects, then used the light probe for 30 minutes to induce slow-wave patterns similar to non-rapid eye movement sleep. After the stimulation, the treated side of the brain showed fewer signs of sleep deprivation when the mice were later allowed to rest. In a memory test the next day, sleep-deprived mice that received the stimulation performed as well as rested mice, spending more time exploring a novel texture. Chiara Cirelli, who led the work, said the results suggest that part of the brain can carry out synaptic maintenance while the animal remains awake. Vladyslav Vyazovskiy of the University of Oxford noted that full sleep involves both NREM and REM stages whose alternation cannot yet be replicated artificially. The researchers intend to test non-invasive transcranial electrical stimulation in humans, though they stress that the method is unlikely to replace natural sleep entirely.
