Fundamental Dynamical Modes Underlying Human Brain Synchronization
Figure 3
(a) Same correlation matrix as in Figure 2, now sorted in order of similarity by the clustering algorithm. (b) Dendrogram of correlation matrix. Levels of the dendrogram correspond to different sets of clusters in the correlation matrix. At the top of the dendrogram, a single branch signifies that all avalanches are in one cluster. Just below this, the dendrogram divides into two branches, representing a set of two clusters. Branching continues further down the dendrogram until every window is in its own family. The red line crosses the dendrogram at minimum of the ratio between intracluster and intercluster distances and indicated that 5 clusters can be identified (note here that one small sized cluster was removed). The 5 corresponding clusters were reported in the sorted correlation matrix (a). (c) The corresponding 5 clusters were reported in the state space, coded by different colors. The probabilities of transition between the different clusters are depicted using different arrow sizes (small: and large: ). Direct cluster-to-cluster transitions were mostly identified between proximal modes in the state space. (c) Matrices of transition probabilities between the characteristic modes defined by clustering, for both the actual and shuffled data.
