Magneto may have been onto something - magnetic brain stimulation can help memory

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Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts.

Experimental study: At least one thing in the experiment was changed to see if it had an impact on the subjects (often people or animals) – eg: changing the amount of time mice spend on an exercise wheel to find out what impact it has on weight loss.

People: This is a study based on research using people.

Stimulating a part of the brain with magnets won't make you one of the X-Men but it could help improve your memory, according to International research. The researchers asked people to memorise words while they stimulated their brains with low frequency repetitive transcranial magnetic stimulation—known as rTMS. The magnetic stimulation was applied to either a part of the brain thought to be involved in memory formation, called the left prefrontal cortex, or an unrelated part of the brain. They found that people performed better on the memory task when the left prefrontal cortex was being stimulated. They also found that this improvement was likely due to the stimulation reducing the power of some brain waves in a different part of the brain involved in attention and perception.

Journal/conference: PLOS Biology

Link to research (DOI): 10.1371/journal.pbio.3001363

Organisation/s: University of Birmingham, University of Glasgow, UK

Funder: S.H. was supported by grants from the European Research Council (Nr. 647954), and the Economic and Social Research Council (ES/ R010072/1).

Media release

From: PLOS

Magnetic stimulation of the brain can improve episodic memory

Inhibitory brain stimulation allows better memorization by reducing the power of beta-waves in the brain

Memories of past events and experiences are what define us as who we are, and yet the ability to form these episodic memories declines with age, certain dementias, and brain injury. However, a study publishing in the open access journal PLOS Biology on September 28th by Mircea van der Plas and Simon Hanslmayr from the University of Glasgow and colleagues, shows that low frequency repetitive transcranial magnetic stimulation—or rTMS—delivered over the left prefrontal cortex of the brain can improve memory performance by reducing the power of low frequency brain waves as memories form.

Based on current knowledge of the brain and the effects rTMS, the researchers hypothesized that they could improve episodic memory, and in the process, generate targets for future memory-related therapies.

The researchers first analyzed past data from 40 college students who had been asked to memorize lists of words. Half of the students received slow rTMS over the left dorsolateral prefrontal cortex while trying to memorize the words, and the other half received rTMS over a control region of the brain. In a new experiment, researchers collected data from 24 college students who each performed a similar memory task under both rTMS conditions.

Analysis of both datasets revealed that memory performance was better for words that were memorized while the left prefrontal cortex was being stimulated. Examining the EEG data that was recorded during the experiments, the researchers found that the slow rTMS applied to the prefrontal region led to reduced power of low-frequency (beta) waves in the parietal region of the brain, which is known to be involved in attention and perception.

Because slow rTMS inhibits brain activity, and the prefrontal cortex inhibits the posterior regions of the brain, van der Plas and co-authors theorize that the slow rTMS disinhibited the activity of the parietal region, leading to enhanced encoding of the words being memorized, and thus improved memory.

van der Plas notes, “Our electrophysiological results suggest that frontal stimulation affects a wider network and improves memory formation by inhibiting parietal areas. These are complex but interesting effects that require further experiments to better understand their neural basis.”

Hanslmayr adds, “We were quite surprised when we saw these effects in the first study, which was designed to investigate a different question. Therefore, we needed to replicate the effects in a second experiment to see whether this is real, and indeed it seems to be.”

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