Double Shock Aids Learning

The brain does not remember everything and one of its key jobs is to cut through the clutter of information and keeping what is important enough to be remembered. How the brain makes this choice has been a subject of many studies. A new study has found how getting scared might leave a permanent memory in our brains and aid learning.

"We believe our findings might help explain how events are selected out for long-term storage from what is essentially a torrent of information encountered during conscious experience," Parsons and Davis wrote in their paper.

Researchers say that animals remember things that occur more than once.

"I describe this effect as ‘priming'. The animal experiences all sorts of things, and has to sort out what's important. If something happens just once, it doesn't register. But twice, and the animal remembers," said, Ryan Parsons, lead author of the study.

To see how fear affects memory, researchers conducted an experiment where rats were exposed to light that followed by a mild shock. They found that a single event of exposure plus shock had no effect whereas anything greater than this made the rats anxious even days later after the experiment. Their anxiety after seeing light showed that they remembered that it will be followed by shock.

The researchers said that rats are less sensitive to light compared to sound and smell. Therefore to train them to avoid light is tougher compared to other stimuli like smell and sound. Also, memories were formed only when the shocks were paired with light impulses.

Researchers feel that this study can also help understanding how learning works in humans. Previous studies have shown that our brain learns new tasks by keeping only the connections that are required and chopping off all other nerve connections.

"This could be a good model for dissecting the mechanisms involved in learning and memory. We're going to be able to look at what's going on in that first priming event, as well as when the long-term memory is triggered," Parsons said.

The study is published in the Journal of Neuroscience.