FIGURE 6.

Thought experiment considering the activation patterns for three subjects (A,B,C). The individual (ground truth) activations of the three subjects are displayed in the colors red, green, and blue. Critically, we assume the true activations to be variable across the subjects. If standard group statistical procedures then are applied on this scenario, only the effective overlap of the subjects is revealed (D). We display this effective overlap in an orange “blob-like” tone in (D), for the sake of illustration we marked the overlap also in the individual subject patterns (A,B,C) using white dots. Under the assumption of high inter-individual variance, this illustration shows the fallacy of spatial group statistics: for none of the subjects the overlap regions were sufficient for representing the brain state, as each subject relied on the involvement of further regions.