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, provides further insight into how our memories are recorded. This study is an extension of work published last year which showed how spatial memories -- in that case, where a volunteer was standing in a virtual reality room -- are recorded in regular patterns of activity in the hippocampus, the area of the brain responsible for learning and memory. To explore how such memories are recorded, the researchers showed ten volunteers three short films and asked them to memorise what they saw. The films were very simple, sharing a number of similar features -- all included a woman carrying out an everyday task in a typical urban street, and each film was the same length, seven seconds long. For example, one film showed a woman drinking coffee from a paper cup in the street before discarding the cup in a litter bin; another film showed a (different) woman posting a letter.
The volunteers were then asked to recall each of the films in turn whilst iside an fMRI scanner, which records brain activity by measuring changes in blood flow within the brain. 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. 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. Researchers found that the key areas involved in recording the memories were the hippocampus and its immediate neighbours. However, the computer algorithm performed best when analysing 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. The rear right area had been implicated in the earlier study, further enforcing the idea that this is where spatial information is recorded. However, it is still not clear what role the front two regions play.
More information:
http://www.sciencedaily.com/releases/2010/03/100311123520.htm
More information:
http://www.sciencedaily.com/releases/2010/03/100311123520.htm