Figure 3

(a) Cumulative (across the 10 fMRI sessions) similarity index \(\Psi _1\), based on the Fowlkes and Mallows comparison measure, for each dendrogram level \(\ell\). \(\Psi _1\) measures the consistency of the corresponding clustering across the fMRI sessions. Specific levels \(\ell ^*_k\) (corresponding to k clusters) are selected as local maxima of this curve (colored dots, same color code as in Figs. 5 and 6). We chose to discard local maxima that are not in ascending order and trivial partitions with too few or too many clusters (grey areas, corresponding to those in panel a) of Fig. 5). (b) Cumulative (across levels \(\ell ^*_k\)) similarity index \(\Psi _2\) for each of the 10 sessions. \(\Psi _2\) indicates how much the clustering obtained from a session is similar to the clusterings from all other sessions. The fMRI session corresponding to the maximum value of \(\Psi _2\) (red dot, corresponding to the correlation matrix \(X^*\) shown above) is chosen as the most representative of the subject.