Algorithm ‘Reads’ Memories

Photo via flickr by paintMonkey

Perhaps we remember more episodes than we realize. Computer programs have been able to predict which of three short films a person is thinking about, just by looking at their brain activity. The research, conducted by scientists at the Wellcome Trust Centre for Neuroimaging at UCL (University College London), provides further insight into how our memories are recorded.

An extension of work which showed how spatial memories are recorded in the hippocampus, this Wellcome Trust-funded study led by Professor Eleanor Maguire looked at episodic’ memories —the complex, everyday memories that include much more information on where we are, what we are doing and how we feel.

To explore how episodic memories are recorded, the researchers showed ten volunteers three short films and asked them to memorize what they saw. The films were very simple, sharing a number of similar features, which included a woman carrying out an everyday task in a typical urban street. For example, one film showed a woman drinking coffee from a paper cup in the street before discarding the cup in a litterbin; another film showed a (different) woman posting a letter.

The volunteers were then asked to recall each of the films in turn while inside an fMRI scanner, which records brain activity by measuring related changes in blood flow. A computer algorithm then studied the patterns and had to identify which film the volunteer was recalling purely by looking at the pattern of their brain activity.

“The algorithm was able to predict correctly which of the three films the volunteer was recalling significantly above what would be expected by chance,” explains Martin Chadwick, lead author of the study. “This suggests that our memories are recorded in a regular pattern.”

Although a whole network of brain areas support memory, the researchers focused their study on the medial temporal lobe, an area deep within the brain believed to be most heavily involved in episodic memory. It includes the hippocampus and its immediate neighbors. However, the computer algorithm performed best when analyzing activity in the hippocampus itself, suggesting that this is the most important region for recording episodic memories. In particular, three areas of the hippocampus —the rear right and the front left and front right areas—seemed to be involved consistently across all participants.

“Now that we are developing a clearer picture of how our memories are stored, we hope to examine how they are affected by time, the aging process and by brain injury,” says Professor Maguire. The results are published in the journal “Current Biology”.

via Wellcome Trust

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