Fuzzy cluster analysis of fMRI data on memory consolidated through elaborative rehearsal by the method of loci

A brain mapping in recalling long term memories consolidated by a mnemonic called the method of loci was carried out using fMRI experiments. A Japanese subject memorized 2000 English sentences, each of which consisted of about 10 words, during the last three years. The brain images when the subject was recalling the sentences were acquired in the activation and baseline epochs. The fMRI signals were analyzed using SPM99 and a modified fuzzy c-means clustering. The clustering results revealed the functional specialization of Broker´s area and visual area. Broader areas in visual cortex are detected.