Electric Brain Stimulation During Sleep Could Boost Memory – Study

Zapping the brain with weak electric currents while asleep could enhance memory, finds a new study by the US researchers.

According to the research team of scientists, including one of Indian-origin, stimulating a certain region of the brain with small doses of electricity during sleep could strengthen a person’s ability to remember things.

The discovery of electrical brain stimulation raises hope for a non-invasive method to help people with conditions like autism and Alzheimer’s disease while they sleep.

In their study, scientists at University of North Carolina (UNC) in the US used transcranial alternating current stimulation (tACS), a technique in which a slight, alternating zap is used to stimulate the brain.

Using the tACS technique, the scientists targeted the current at brain waves called sleep spindles which are believed be involved in screening out and storing memories.

“We work with the brain, that’s really unique about what we do. We listen in to brain activity and can boost what the brain already wants to do,” said the study’s senior author, Flavio Frohlich, who is an assistant professor of psychiatry at the Neuroscience Center at the University of North Carolina in Chapel Hill. “We know there are a number of disorders of the brain where sleep spindles are impaired,” she said.

To see the memory-enhancing effects of gentle brain-zap on these short electrical wavelengths investigators gave 16 healthy young men two common memory tasks to undertake before going to sleep and then tested them the next morning.

The study volunteers were tested twice- one after having tACS and once after having placebo stimulation while asleep.

For the tACS stimulation, Frohlich’s team placed electrodes at key points on each participant’s scalp and passed a weak current through it that was synced to their natural sleep spindles. Each morning, the investigators asked all the participants to perform the same memory tests.

Although no improvement in test scores for associative word-pairing was found, but a significant improvement in the motor tasks was found among tACS receivers, compared to those who received sham brain zap.

“This demonstrated a direct causal link between the electric activity pattern of sleep spindles and the process of motor memory consolidation,” Frohlich said.

“We hope that targeting these sleep spindles could be a new type of treatment for memory impairment and cognitive deficits,” added Caroline Lustenberger, who is a postdoctoral fellow at Frohlich lab.

The findings were published online in the journal Current Biology on July 28.