Laser light treatment presents new therapy for improving short-term memory

Ever stood in a room, mouth agape, trying desperately to remember what you came in to get… or forgotten someone’s name as soon as they’ve said it? Scientists might soon be able to help you with this.

Described as the ‘scratch pad’ of recall, short-term or working memory typically involves remembering and processing information at the same time and holding small chunks of information for short periods – usually for around 10 to 60 seconds.

Now, a collaboration of researchers in China and the UK has shown that applying certain wavelengths of laser light to parts of the brain can result in working memory improvements of up to 25%.

Diagram of human brain showing main parts including prefrontal cortex
Diagram of human brain showing main parts including prefrontal cortex. Credit: jambojam/Getty Images

The researchers applied a technique to human subjects, called transcranial photobiomodulation (tPBM) for 12 minutes to the right prefrontal cortex – an area known to be important for higher level cognitive and working memory functioning.

The treatments varied in energy of the laser and treatment location.

Out of the 90 participants aged from 18 to 25, those who received laser light at wavelengths of 1064 nm to the right prefrontal cortex were able to recall the colour or orientation of between four and five objects from a specific set. Those who received treatment at shorter (higher energy) wavelengths, to the left prefrontal cortex or other areas of the brain, or who were given a placebo or inactive tPBM, were only able to remember between three and four of the objects.

Read more: Mapping memories in the brain

The effects were backed up by the EEG results, which demonstrated brain activity complementary to the improvements in memory.

Studies have already demonstrated that laser light treatment can improve working memory in mice, while tPBM treatment in humans has shown improvements in accuracy, reaction time, attention and emotion modulation.

Short-term memory improved with laser light applied to the prefrontal cortex
Laser light of 1064 nm applied to the prefrontal cortex resulted in better short-term memory -related recall for participants.

Although researchers admit that the process is not yet fully understood (nor do they know how long the effects will last), they are hopeful the treatment could provide relief to sufferers of some conditions.

“People with conditions like ADHD (attention deficit hyperactivity disorder) or other attention-related conditions could benefit from this type of treatment,” said Dongwei Li, paper co-author and a visiting PhD student in the University of Birmingham’s Centre for Human Brain Health. “A treatment which is safe, simple and non-invasive, with no side-effects.”

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