As one ages, memory tends to decline. However, even young, healthy individuals can experience memory lapses. A new study has found that the application of an electrical boost to the brain of a healthy person can improve memory performance. The research may lead to methods to improve memory in seniors. The findings were published on August 28 in Science by researchers at Northwestern University’s Feinberg School of Medicine in Chicago, Illinois.
The researchers used a procedure known as transcranial magnetic stimulation (TMS), which is a therapy that is increasingly being used for psychiatric disorders; it involves placing fist-sized coiled magnets on the scalp to stimulate different brain regions. At present, how or why TMS is not known, it has found to benefit some patients. In 2013, the Food and Drug Administration (FDA) approved several TMS devices for treating migraines and depression. Previous studies have reported that it can improve performance on different types of memory tests; however, only a handful of studies have examined whether the benefits persist after stimulation stops or assessed how stimulation affects the brain's memory circuits.
The study group comprised 16 healthy adults who were between the ages of 21 and 40. They used functional MRI scanners to make detailed maps of the subjects’ brains; the hippocampus, a brain region key to memory, was located, and its connections to another brain region called the parietal cortex was determined. Functional MRI scans of brain activity image greater neuronal traffic between the two areas when individuals are performing memory-related tasks; in addition, lesions between the areas can result in severe memory deficits.
The participants first underwent a baseline memory test; then, the brain stimulation sessions began in which rapid-fire magnetic pulses were focused on a fingertip-sized area toward the back of the skull for 20 minutes per day. The location of the stimulation differed slightly between the participants, based on brain scans showing their unique connections between the parietal cortex and hippocampus. After five days, the participants were given a 24-hour break from stimulation and asked to repeat the memory test. The subjects who had received TMS improved their scores by about 20-25%, whereas the controls who had not received the stimulation exhibited little to no improvement. The brain scans also showed increases in the amount of communication between the hippocampus and parietal cortex in subjects who received the stimulation. The more the two regions worked together, the better people performed on the memory test, Voss says.
It is possible that in the future TMS can become a treatment for memory problems in individuals with neurological conditions such as Alzheimer’s disease. Therefore, the researchers are planning a study that will test the procedure on individuals with early-stage memory loss.