The study confirmed that Forgotten memories can be retrieved by the stimulating specific brain

A study by UCLA  psychologists found that a certain region of the brain plays in memory recall.

They published in the journal, show the first time that using electrical current to stimulate the left rostrolateral prefrontal cortex improves the ability to retrieve the memory.

“We found dramatically improved memory performance when we increased the excitability of this region,” said Jesse Rissman, a UCLA assistant professor of psychology and the study’s senior author.

The left rostrolateral prefrontal cortex is very important in integrating and monitoring information processed in other areas of the brain. It is also important for high-level thoughts.  The left rostrolateral prefrontal cortex is located behind the left side of the forehead, between hairline and eyebrows.

Rissman said “We think this brain area is particularly important in accessing knowledge that you formed in the past and in making decisions about it”

Experiment

Researchers conduct an experiment with three groups each group contains 13 women and 11 men whose average age is 20.

They showed 80 words on the computer screen to the participant. For each word participant were instructed to either imagine themselves or other interacting with that word.

The following day, participants come to the laboratory for tests – one their reasoning ability, one their memory and one their visual perception. Participants wore a device that sent electrical signals on their excitation of neurons in the left rostrolateral prefrontal cortex. Rissman said “Increasing their excitability makes neurons more likely to fire, which enhances the connections between neurons”

This technique is called transcranial direct current stimulation (tDCS), which gives to the most people mild tingling sensation for a few minutes, said Andrew Westphal.

In the first half participant received “sham” stimulation that means the device just gives the sensation that something was happening but after that turn-off. With this researchers know how well each participant performed under normal condition.

In the next half, one group of participants received an electrical current that increases neurons excitability, the second group received current that suppresses neurons activity and in a third group, they receive normal stimulation as all in the first half. Researchers analyzed which group had the best results.

Researchers notice that there was no difference in the first half of the study when no brain stimulation or sham stimulation given.

But in the second half difference can be seen easily. Memory scores for the group who receive neurons stimulation were 15.4% points higher than their scores in the first half.

Memory score for those who receive sham stimulation during both sessions increased by 2.6% points from first to the second session – which was statistically insignificant change due to their increased familiarity with the task according to the paper.

And memory scores for those participants whose neuron activity suppressed increased by 5% which also was statistically insignificant.

Rissman said that our previous neuroimaging studies showed the left rostrolateral prefrontal cortex was highly engaged during memory retrieval.

Now the fact that people do in their memory test when they excite the left rostrolateral prefrontal cortex with electrical stimulation also provides casual evidence that it contributes to the act of memory retrieval.

“We didn’t expect the application of weak electrical brain stimulation would magically make their memories perfect, but the fact that their performance increased as much as it did is surprising and it’s an encouraging sign that this method could potentially be used to boost people’s memories.”

Conclusion

When researchers do the same experiment for reasoning and perception task they noticed no difference in their performance.

People do forget names and other things because sometimes they hear first they don’t pay attention so no memory even formed. In that case, electrical stimulation wouldn’t be helpful.

Rissman said other areas of the brain also play important roles in memory retrieving. Their future study will aim to better understand the roles of the other part of the brain.

Source

Journal of Cognitive Neuroscience   


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