Identification and Classification of Hubs in Brain Networks
Figure 1
Connection matrices and matching index matrices for data sets examined in this study.
Plots show structural connections (left panels) and matching index (right panels). Connection patterns are represented as binary connection matrices Cij, with existing connections (edges) indicated by a filled (black) square (cij = 1). No distinction is made between connections that have been shown to be absent and connections that are unknown; all are represented by a white square (cij = 0). Main diagonals are indicated in grey and self-connections are excluded (cii = 0). From top to bottom: (A) Macaque cortex (N = 47, K = 505). (B) Cat cortex (N = 52, K = 820). Panels on the right show the matching index matrix Mij calculated from the connection matrix following Hilgetag et al. [6]. The matching index scales between 0 (no match) and 1 (perfect match), and mij = mji. The arrangement of brain regions for each of the four matrices was arrived at as follows. The Mij matrix was converted to a distance matrix, from which a hierarchical cluster tree was computed using a consecutive linking procedure based on farthest inter-cluster distances. This resulted in a linear ordering of areas based on cluster membership and inter-cluster distances. The ordering was rotated such that visual areas appear topmost.
