Electrical stimulation may boost memory during sleep

U of A study shows results in mice but researchers unable to say how it happens

EDMONTON New research from the University of Alberta gives clues on how to improve your memory: it involves electrical stimulation and sleep.

The study, conducted with the University of Lethbridge, studied the brain activity of mice when electrical waves were applied to the front of their heads during deep sleep.

“Previous experimenters have suggested that that kind of stimulation does in fact influence memory. The only problem is we don’t understand how,” Clay Dickson, professor of psychology at the U of A, said Wednesday.

Anastasia Greenberg, who led the research while completing her PhD with Dickson, discovered that by using voltage-sensitive dye, they were able to record how mice brain activity was altered by electrical stimulation.

The particular neural activity the researchers were interested in was slow-wave activity, which occurs most frequently when you’re first falling asleep.

If you’re sleep-deprived, you will have more of this restorative stage of sleep, Dickson said.

It also tends to occur during naps.

Without electrical stimulation, the study found the pattern of slow-waves varied, but when the electrical current was applied, the pattern was suddenly uniform, repeating itself over and over again.

Based on previous studies’ findings that there is a correlation between electrical stimulation and memory retention, Dickson said researchers can hypothesize the uniform slow-wave pattern is also related to memory.

“One idea, in terms of brain activity, is that (sleep) provides a time in which the brain can do things that it couldn’t do while you’re using it,” Dickson said.

“Maybe what sleep is doing is it’s allowing the brain to actually solidify those experiences that you had during wakefulness.”

He said it is possible the repetitive patterns created by electrical stimulation are akin to a replay mode so that memories are further and further cemented into the brain.

Future research is required, but Dickson said he imagines this research could lead to helping individuals with memory disorders or students in retaining information.

It is doubtful people would be able to choose what information they want to remember, since the electrical stimulation only seems to affect brain activity occurring during sleep.

“It’s not fine-tuned enough to be able to pick a specific memory. It probably has to do with the kind of information that people may have just experienced during wakefulness,” Dickson said.