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 inside 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. The results are published in the journal Current Biology.
"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 - an area which Professor Maguire and colleagues have studied extensively in the past.
They 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.
thinkahol * on 16 Jul 11Meditation may have potential to change the brain's physical structure, researchers at the University of California, Los Angeles, have found. People who meditate have stronger connections between brain regions and show less age-related brain atrophy, according to the researchers. Stronger connections influence the ability to rapidly relay electrical signals in the brain. And significantly, these effects are evident throughout the entire brain, not just in specific areas. The study consisted of 27 active meditation practitioners (average age 52) and 27 control subjects, who were matched by age and sex. The meditation and the control group each consisted of 11 men and 16 women. The number of years of meditation practice ranged from 5 to 46; self-reported meditation styles included Shamatha, Vipassana and Zazen, practiced by about 55 percent of the meditators, either exclusively or in combination with other styles. Pronounced structural connectivity The researchers used a type of brain imaging known as diffusion tensor imaging (DTI), a relatively new imaging mode that provides insights into the structural connectivity of the brain. They found that the differences between meditators and controls are not confined to a particular core region of the brain but involve large-scale networks that include the frontal, temporal, parietal and occipital lobes and the anterior corpus callosum, as well as limbic structures and the brain stem. They found pronounced structural connectivity in meditators throughout the entire brain's pathways. The greatest differences between the two groups were seen within the corticospinal tract (a collection of axons that travel between the cerebral cortex of the brain and the spinal cord), the superior longitudinal fasciculus (long bi-directional bundles of neurons connecting the front and the back of the cerebrum), and the uncinate fasciculus (white matter that connects parts of the limbic system, such as the hippocampus and amygdala, wi
