Brain Constantly Upgrades Memories

Memories aren't static and are re-written regularly, according to a new study.

We'd like to imagine our brain to be a factory where memories are made, stored and pulled out each time we want to remember an event. However, science has shown that memories are constantly edited and updated to suit current environment. This up-gradation of memories, science says, helps us process new information.

In the present study, researchers at Northwestern University and colleagues used brain scans and eye tracking devices to understand how memories get re-written.

Their study was based on 17 men and women who were shown 168 objects in different backgrounds such as an underwater scene or a desert. Next, they were given a set of backgrounds and asked to place the object where they think they saw it the first time. Researchers found that all participants failed to place the object in the right place.

In another experiment, researchers asked these participants to place the object against a background. In this test, they were given three choices; they could either place the object in the original scene; place it in the background they saw in the previous test; or place it in a new location.

"People always chose the location they picked in part 2," Donna Jo Bridge, at Northwestern University Feinberg School of Medicine and lead author of the study, said in a news release. "This shows their original memory of the location has changed to reflect the location they recalled on the new background screen. Their memory has updated the information by inserting the new information into the old memory."

Participants took the tests while hooked to a brain scanner, which helped researchers see how the brain was working. Researchers also used an eye-tracking device to analyze how the participants were making the choices.

"Our memory is not like a video camera," Bridge said. "Your memory reframes and edits events to create a story to fit your current world. It's built to be current."

The study is published in the Journal of Neuroscience.                                           

Hippocampus- the special effects team of the brain

According to the study authors, hippocampus acts as an editor and upgrades memories to suit current environment.

Previous research has shown that hippocampus is associated with long-term memories and that it is affected by stress and poor blood flow. The present study might explain why people with mental disease such as Alzheimer's and Post Traumatic Stress Disorder might have problems with memories.

According to researchers, brains of these people might be stuck on some event and have problems upgrading memories.  Other researchers are already trying to find ways to alter or even delete bad memories, which could help PTSD sufferers imagine a new future.

Eyewitness Testimony

The present study strengthens the notion that humans aren't reliable eyewitnesses because our memories are changing constantly, an idea that has been around for many years.

"Our memory is built to change, not regurgitate facts, so we are not very reliable witnesses," Bridge said.