Activity in the parahippocampal cortex (PHC), a part of the brain, predicts how well we remember images, researchers from MIT reported in the journal NeuroImage. The higher the activity within the PHC is before we are shown an image, the smaller the chance that we will remember it later, Professor John Gabrieli and team explained.

Gabrieli said:

“The new study, published in the journal NeuroImage, found that when the PHC was very active before people were shown an image, they were less likely to remember it later. “When that area is busy, for some reason or another, it’s less ready to learn something new.”

The scientists say theirs is the first study to examine what impact PHC activity might have on visual memory. PHC wraps around the hippocampus, a part of the brain which is vital for memory formation. Julie Yoo, a postoc at the McGovern Institute, MIT, was the lead author.

Previous studies had linked the PHC to the recollection of visual scenes.

Volunteers were asked to look at 250 color photos of outdoor and indoor scenes while lying in a fMRI (functional magnetic resonance imaging) scanning device. Later on they were given 500 scenes to look at – these included the 250 they had seen before. The aim was to see how well they could remember the first lot of images.

The scans showed that when PHC activity had been lower before looking at the scenes, they could remember them better.

The area of activation was always in the PHC for every person, however, which parts in the PHC were more or less active varied from person-to-person.

In another experiment, the scientists used real-time fMRI. This device can monitor the state of a person’s brain from moment to moment – it can determine whether that person’s brain is “ready” or “not ready” to remember images.

The states were used as triggers to show new visual scenes. When the brain was in a “ready” state, the person could remember them better.

The scientists say that in theory, their method could be utilized to select the ideal moments for students to learn new material, or to monitor employees who are required to be alert.

Gabrieli said:

“That’s what we would like to think – that we are able to measure states of receptivity for learning, or preparedness for learning. In terms of how that would be translated to real life, there are still a few steps to go.”

Unfortunately, fMRI scanners are bulky machines that cannot be carried around. Portable EEG (electroencephalography) are possible alternatives, the authors added. The scientists are currently working on how to use EEG to measure PHC activity.

Written by Christian Nordqvist