Electric current treatments may be the next big thing doctors use to improve memory. Researchers from Northwestern University have found that delivering a noninvasive electric current to the brain improves learning and memory. Their study was published yesterday in the journal Science.
Magnetic pulses known as Transcranial Magnetic Stimulation (TMS), could potentially treat ailments such as traumatic brain injury, stroke, early-stage Alzheimer's disease, and other memory-related conditions.
“This noninvasive stimulation improves the ability to learn new things. It has tremendous potential for treating memory disorders,” said senior study author Joel Voss, an assistant professor of medical social sciences and neurology at Northwestern's Feinberg School of Medicine, in a press statement. “We show for the first time that you can specifically change memory functions of the brain in adults without surgery or drugs, which have not proven effective.”
Here’s how it works: You can’t directly stimulate the hippocampus — a small brain structure that controls memory — because it’s too deep in the brain. Instead, the team used MRI scans to pinpoint a part of the brain connected to the hippocampus that is just a centimeter below the surface of the skull. When researchers stimulated the area with TMS, it was easier for study subjects to grasp new information.
Voss' team found that recalling events requires many brain regions to work together, in sync with the hippocampus. The electric current syncs up a whole network of brain regions connected to the hippocampus.
This study is the first to document that TMS can boost memory for up to 24 hours after the treatment.
Boosting Memory with TMS
In the study, 16 adults ages 21 to 40 had detailed scans taken of their brains. Researchers also recorded 10 minutes of the participants' brain activity in the MRI scanner so they could make out each person’s individual brain structure.
Then the participants had a memory test that included spotting faces and remembering words. Once a baseline was established, half of the participants were given TMS stimulation for 20 minutes a day, five days in a row. The other half received a sham TMS treatment. During that time, subjects also had other MRI scans and tests of word and face pairings to determine how their memory had changed.
At least 24 hours after the last TMS session, the subjects were tested again.
The researchers found that subjects performed better on memory tests following brain stimulation. It took three days of TMS to notice positive results.
“They remembered more face-word pairings after the stimulation than before, which means their learning ability improved,” Voss said. “That didn't happen for the placebo condition or in another control experiment with additional subjects.”
MRI scans also showed that subjects' brain regions became more synchronized with one other and with the hippocampus. The greater the boost in connectivity between specific parts of the brain network, the better the subjects performed on the test.
“The more certain brain regions worked together because of the stimulation, the more people were able to learn face-word pairings,” Voss said.
The Future of TMS Therapy
Voss worked with people who had normal memory function, but he said that people with impaired memory could see some significant changes once exposed to TMS. He plans to study that effect in an upcoming trial.
“This opens up a whole new area for treatment studies where we will try to see if we can improve function in people who really need it,” Voss said.
He said that the brain network targeted in this study plays a role in memory disorders caused by stroke, brain injury, old age, and conditions such as Alzheimer’s.
“Because our method specifically enhances this network, it holds promise for treating memory disorders, although substantial further research will be needed to prove that it is safe and effective for patients,” Voss said.