Topological Randomness and Number of Edges Predict Modular Structure in Functional Brain Networks

In a recent paper, Bassett et al. (2011) have analyzed the static and dynamic organization of functional brain networks in humans. We here focus on the first claim made in this paper, which states that the static modular structure of such networks is nested with respect to time. Bassett et al. (2011) argue that this graded structure underlines a "multiscale modular structure". In this letter, however, we show that such a relationship is substantially mediated by an increase in the random variation of the correlation coefficients computed at different time scales.
Comment: Submitted as a letter to the Proceedings of the National Academy of Sciences (PNAS)