ICA of fMRI group study data.

This paper proposes to extend independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data from single subjects to simultaneous analysis of data from a group of subjects. This results in a set of time courses which are common to the whole group, together with an individual spatial response pattern for each of the subjects in the group. The method is illustrated using data from two fMRI experiments. The results show that: (a) ICA is capable of extracting nontrivial task related components without any a priori information about the fMRI experiment; (b) in analysis of group data, ICA identifies components common to the whole group as well as components manifested in single subjects only.