Abstract
The modified fuzzy c-means (FCM) clustering is used for exploratory analysis of fMRI signals in which the cluster centroids represent typical hemodynamics responses of relatively wide brain regions. This paper shows how blood oxygen level-dependent (BOLD) signals can be approximated by a small number of cluster centroids and presents
a framework that allows FCM clustering technique to be implemented in conjunction with the general linear model (GLM). The approach is illustrated with fMRI experiments of recalling sentences.
Because the recalling by way of mnemonics is a heavy task for the brain, the wide brain regions activate similarly. This makes it difficult to distinguish the role of brain regions. The exploratory approach clarifies the slightly different responses of different brain regions to the tasks of recalling sentences. The visual areas activate more than the temporal and frontal areas. The visual areas seem to play a significant role in recalling sentences.
