A new study found that the brain edits past memories to relate them to present memories.
Researchers from the Northwestern University Feinberg School of Medicine led by Donna Jo Bridge, concluded that the brain revises memory of the past and update and combine them with new experiences. The brain does that so we can adapt to a dynamic environment and help us live in the present.
They recruited a total of 17 men and women to take tests while inside an MRI scanner. The procedure was for them to accurately measure the participant's brain activities and the eye movements. Eye movements are believed to say more about what inside a person's memory.
During the initial test, the participants were asked to study 168 object locations on a computer screen with different backgrounds. After that, they were shown new backgrounds and instructed to put the object in its original location. They observed that the participants always failed to place the objects in its original place.
For the last part of the experiment, the participants were presented with backgrounds containing three objects. The objects in each background were placed in its original location, the location chosen by the participant in the second test, and a new location.
After the test, the researchers concluded that the participants would always place the objects in a wrong location and when asked to choose among the choices, they were most likely to choose the image they created.
The MRI scanning also showed that the editing of the events takes place in hippocampus -- the brain's film editor and special effects team. It is responsible for the consolidation of short-term and long-term memories.
"People always chose the location they picked in part 2. 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," said Bridge said in a university press release.
A perfect memory is non-existent. "Everyone likes to think of memory as this thing that lets us vividly remember our childhoods or what we did last week. But memory is designed to help us make good decisions in the moment and, therefore, memory has to stay up-to-date. The information that is relevant right now can overwrite what was there to begin with," added Joel Voss, senior author of the paper and an assistant professor of medical social sciences and of neurology at Feinberg.
This study will be published Feb.5 in the Journal of Neuroscience.
