FIG. 4.

Degree distributions. The degree distributions of the networks with connectivity based on XSampEnt (blue) and LinCorr (red) are shown. The x-axis denotes the node degree, and the y-axis denotes the complimentary cumulative distribution function (1-CDF) describing the abundance of nodes with a certain degree or higher. The degree distributions from the XSampEnt networks follow a scale-free distribution characterized by a straight line on a log–log plot, indicating that there are a few nodes with an extremely large degree or mega-hubs; while the vast majority of nodes have just a few connections at most. On the other hand, the degree distributions from the LinCorr networks are exponentially truncated. Although high-degree nodes exist in the LinCorr networks, with k≈20, such nodes have far less connections than the mega-hubs observed in the XSampEnt networks. Color images available online at www.liebertpub.com/brain