might represent periods of specialized information processing when information is less readily exchanged between modules. During time periods when few excur- sions take place, functional networks are less modular and feature communities that are not as well-defined; these periods might represent times during which information is more freely exchanged across community boundaries. This in- terpretation agrees with earlier results from Liegeois et al. (2015) in which the authors reported oscillatory behavior between periods of high and low modu- larity, associated with a transient de-coupling of functional connections from the underlying anatomical network. It is also somewhat in line with earlier re- sults (Zalesky et al., 2014) reporting that functional networks flipped between periods of high and low global efficiency. We expect that further analysis will reveal that the high efficiency states reported by Zalesky et al. (2014) would correspond to the low modularity states observed here while the low efficiency states would be more closely related to high-modularity networks. This follows from the observation that greater global efficiency scores are associated with disordered (i.e. more random) networks, whereas higher modularity scores are associated with highly ordered (i.e. clustered) networks (Watts and Strogatz, 1998). Future work can be directed to better understand the relationships of these states to one another. Interestingly, our findings suggest that mass-excursion periods are typified by the dissociation of default mode regions dissociating from other systems and forming more distinct modules. One possible explanation for this observation is that instants during which default mode regions dissociate from other regions correspond to periods of introspective thought or mind-wandering, which may not require that system is integrated across multiple systems. This hypothesis is at least partly supported by previous studies that suggest that the default mode network’s dynamic connectivity tracks daydreaming (Kucyi and Davis, 23