Transcranial Magnetic Stimulation of brain boosts memory

August 28, 2014, Northwestern University

Stimulating a particular region in the brain via non-invasive delivery of electrical current using magnetic pulses, called Transcranial Magnetic Stimulation, improves memory, reports a new Northwestern Medicine study.

The discovery opens a new field of possibilities for treating memory impairments caused by conditions such as stroke, early-stage Alzheimer's disease, , cardiac arrest and the memory problems that occur in healthy aging.

"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," said senior author Joel Voss, assistant professor of medical social sciences at Northwestern University Feinberg School of Medicine. "This noninvasive stimulation improves the ability to learn new things. It has tremendous potential for treating memory disorders."

The study will be published August 29 in Science.

The study also is the first to demonstrate that remembering events requires a collection of many to work in concert with a key memory structure called the hippocampus – similar to a symphony orchestra. The electrical stimulation is like giving the brain regions a more talented conductor so they play in closer synchrony.

"It's like we replaced their normal conductor with Muti," Voss said, referring to Riccardo Muti, the music director of the renowned Chicago Symphony Orchestra. "The brain regions played together better after the stimulation."

The approach also has potential for treating mental disorders such as schizophrenia in which these brain regions and the hippocampus are out of sync with each other, affecting memory and cognition.

TMS Boosts Memory

The Northwestern study is the first to show TMS improves memory long after treatment. In the past, TMS has been used in a limited way to temporarily change brain function to improve performance during a test, for example, making someone push a button slightly faster while the brain is being stimulated. The study shows that TMS can be used to improve memory for events at least 24 hours after the stimulation is given.

Finding the Sweet Spot

It isn't possible to directly stimulate the hippocampus with TMS because it's too deep in the brain for the magnetic fields to penetrate. So, using an MRI scan, Voss and colleagues identified a superficial brain region a mere centimeter from the surface of the skull with high connectivity to the hippocampus. He wanted to see if directing the stimulation to this spot would in turn stimulate the hippocampus. It did.

"I was astonished to see that it worked so specifically," Voss said.

Stimulating a region in the brain with non-invasive electrical current using magnetic pulses (Transcranial Magnetic Stimulation) improves memory, reports a new Northwestern Medicine study in Science. Credit: Erin White, Northwestern University

When TMS was used to stimulate this spot, regions in the brain involved with the hippocampus became more synchronized with each other, as indicated by data taken while subjects were inside an MRI machine, which records the blood flow in the brain as an indirect measure of neuronal activity.

The more those regions worked together due to the stimulation, the better people were able to learn new information.

How the Study Worked

Scientists recruited 16 healthy adults ages 21 to 40. Each had a detailed anatomical image taken of his or her brain as well as 10 minutes of recording brain activity while lying quietly inside an MRI scanner. Doing this allowed the researchers to identify each person's network of brain structures that are involved in memory and well connected to the hippocampus. The structures are slightly different in each person and may vary in location by as much as a few centimeters.

"To properly target the stimulation, we had to identify the structures in each person's brain space because everyone's brain is different," Voss said.

Each participant then underwent a memory test, consisting of a set of arbitrary associations between faces and words that they were asked to learn and remember. After establishing their baseline ability to perform on this memory task, participants received 20 minutes a day for five consecutive days.

During the week they also received additional MRI scans and tests of their ability to remember new sets of arbitrary word and face parings to see how their memory changed as a result of the stimulation. Then, at least 24 hours after the final stimulation, they were tested again.

At least one week later, the same experiment was repeated but with a fake placebo stimulation. The order of real stimulation and placebo portions of the study was reversed for half of the participants, and they weren't told which was which.

Both groups performed better on memory tests as a result of the brain stimulation. It took three days of stimulation before they improved.

"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."

In addition, the MRI showed the stimulation caused the brain regions to become more synchronized with each other and the . The greater the improvement in the synchronicity or connectivity between specific parts of the network, the better the performance on the memory test. "The more certain brain regions worked together because of the stimulation, the more people were able to learn face-word pairings, " Voss said.

Using TMS to stimulate memory has multiple advantages, noted first author Jane Wang, a postdoctoral fellow in Voss's lab at Feinberg. "No medication could be as specific as TMS for these memory networks," Wang said. "There are a lot of different targets and it's not easy to come up with any one receptor that's involved in memory."

The Future

"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.

His current study was with people who had normal memory, in whom he wouldn't expect to see a big improvement because their brains are already working effectively.

"But for a person with damage or a memory disorder, those networks are disrupted so even a small change could translate into gains in their function," Voss said.

In an upcoming trial, Voss will study the 's effect on people with early-stage memory loss.

Voss cautioned that years of research are needed to determine whether this approach is safe or effective for patients with Alzheimer's disease or similar disorders of .

Explore further: Mechanism behind the activation of dormant memory cells discovered

More information: "Targeted enhancement of cortical-hippocampal brain networks and associative memory," by J.X. Wang et al. Science, 2014. www.sciencemag.org/lookup/doi/ … 1126/science.1252900

Related Stories

Mechanism behind the activation of dormant memory cells discovered

February 20, 2014
The electrical stimulation of the hippocampus in in-vivo experiments activates precisely the same receptor complexes as learning or memory recall. This has been discovered for the first time and the finding has now been published ...

Study results indicate brain structures outside the hippocampus may support face recognition

June 24, 2014
(Medical Xpress)—A team of neuroscientists and psychologists with members from several universities in the U.S. has found that people with damage to their hippocampus are still able to recognize faces, even when they cannot ...

Brain stimulation shows early promise against Alzheimer's

May 6, 2014
(HealthDay)—Four of six Alzheimer's patients responded to deep brain stimulation in a pilot study, German researchers report.

GW leads clinical trial to reduce epileptic seizures in people with temporal lobe epilepsy

June 25, 2014
A first-of-its-kind clinical trial at the George Washington University (GW) Medical Faculty Associates employs low-frequency deep brain stimulation to potentially help reduce epileptic seizures in patients with mesial temporal ...

Could your brain be reprogrammed to work better?

August 6, 2014
(Medical Xpress)—Researchers from The University of Western Australia have shown that electromagnetic stimulation can alter brain organisation which may make your brain work better.

Tickling the brain with magnetic stimulation improves memory in schizophrenia

March 12, 2013
Cognitive impairments are disabling for individuals with schizophrenia, and no satisfactory treatments currently exist. These impairments affect a wide range of cognition, including memory, attention, verbal and motor skills, ...

Recommended for you

Brain activity linked to stress changes chemical codes

April 24, 2018
Five years ago, a team of University of California San Diego neurobiologists published surprising findings describing how rats' brain cells adopted new chemical codes when subjected to significant changes in natural light ...

In Huntington's disease, heart problems reflect broader effects of abnormal protein

April 24, 2018
Researchers investigating a key signaling protein in Huntington's disease describe deleterious effects on heart function, going beyond the disease's devastating neurological impact. By adjusting protein levels affecting an ...

Imagined and actual movements are controlled by the brain in the same way

April 24, 2018
A new study from Karolinska Institutet in Sweden shows that imagined movements can change our perception in the same way as real, executed movements do. The research, which is presented in the scientific journal Nature Communications, ...

Scientists develop new method that uses light to manage neuropathic pain in mice

April 24, 2018
For patients with neuropathic pain, a chronic condition affecting 7 to 8 percent of the European population, extreme pain and sensitivity are a daily reality. There is currently no effective treatment. Scientists from EMBL ...

Animal cyborg—behavioral control by activating 'toy craving' circuit

April 24, 2018
Children love to get toys from parents as presents. This craving for objects also underlies object hoarding disorders and shopping addiction. However, the biological causes of object pursuit have remained unknown. Part of ...

Heading—not collisions—cognitively impairs players

April 24, 2018
Worse cognitive function in soccer players stems mainly from frequent ball heading rather than unintentional head impacts due to collisions, researchers at Albert Einstein College of Medicine have found. The findings suggest ...

5 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

LaPortaMA
1 / 5 (2) Aug 28, 2014
LaPortaMA
1.7 / 5 (3) Aug 28, 2014
HOW LONG before this technology shows up at a NSA/governnent office near you?
http://www.imdb.c...md_md_nm
RobertKarlStonjek
5 / 5 (1) Aug 28, 2014
Alzheimer's, dementia and stroke patients suffer retrograde amnesia. The study above only tested antegrade memory and learning ability.

Alzheimer's patients biggest problem is the loss of historical (retrograde) memories. The formation of new memories is also effected, but it is the loss of established episodic memory that is disrupted.

This can be caused by
a) the loss of function of the retrieval mechanism;
b) the degradation of the memory itself;
c) some combination of the two.

What is tested above is the efficiency of laying down OR retrieving memory over a relatively short period. No indication of which (laying down OR retrieving) is given by the experiment.

Thus, while it is a positive step, the article is quite wrong in its claims for the study.
Sinister1812
5 / 5 (1) Aug 28, 2014
It's hard to imagine when it will become available to patients. If it ever does.
arieh_shishirin
not rated yet Aug 29, 2014
Healthy/natural aging : an oxymoron. aging damage isn't part of the personality or natural makeup of that person, its developmental side effects, wear and tear.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.