Rich club organization supports a diverse set of functional network configurations

Abstract

Brain function relies on the flexible integration of a diverse set of segregated cortical modules, with the structural connectivity of the brain being a fundamentally important factor in shaping the brain"s functional dynamics. Following up on macroscopic studies showing the existence of centrally connected nodes in the mammalian brain, combined with the notion that these putative brain hubs may form a dense interconnected "rich club" collective, we hypothesized that brain connectivity might involve a rich club type of architecture to promote a repertoire of different and flexibly accessible brain functions. With the rich club suggested to play an important role in global brain communication, examining the effects of a rich club organization on the functional repertoire of physical systems in general, and the brain in particular, is of keen interest. Here we elucidate these effects using a spin glass model of neural networks for simulating stable configurations of cortical activity. Using simulations, we show that the presence of a rich club increases the set of attractors and hence the diversity of the functional repertoire over and above the effects produced by scale free type topology alone. Within the networks" overall functional repertoire rich nodes are shown to be important for enabling a high level of dynamic integrations of low-degree nodes to form functional networks. This suggests that the rich club serves as an important backbone for numerous coactivation patterns among peripheral nodes of the network. In addition, applying the spin glass model to empirical anatomical data of the human brain, we show that the positive effects on the functional repertoire attributed to the rich club phenomenon can be observed for the brain as well. We conclude that a rich club organization in network architectures may be crucial for the facilitation and integration of a diverse number of segregated functions.

Cortical rich club regions can organize state-dependent functional network formation by engaging in oscillatory behavior

“…Additionally, simulation studies employing a steady-state attractor model have suggested that cortical hubs, and specifically the rich club, may allow the brain to sustain a large functional repertoire characterized by diverse configurations of peripheral, i.e. low degree, regions around a stable high-degree core (Deco, Senden, & Jirsa, 2012;Senden, Deco, de Reus, Goebel, & van den Heuvel, 2014). Similar observations have been made in studies using oscillatory neural mass models showing that the rich club can facilitate the synchronization among groups of cortical regions (Gollo, Zalesky, Hutchison, van den Heuvel, & Breakspear, 2015;Schmidt, LaFleur, de Reus, van den Berg, & van den Heuvel, 2015).…”

Rich Club Organization and Cognitive Performance in Healthy Older Participants

“…Rich club and feeder connections, seen in this study to be associated with A/E performance, have been hypothesized to play a central role in the communication between subcomponents of such networks ( Van den Heuvel & Sporns, 2013a). Combined stronger rich club-to-rich club and rich clubto-non-rich club connections may conceivably allow for more efficient neural communication from peripheral modules-where local processing occurs-to hub regions, with the latter argued to enrich the overall functional repository of the brain at the system's level (Senden et al, 2014).…”

“…Moreover, this set of hubs appears to be more highly connected to other highdegree nodes than predicted by chance, forming a group of highly interconnected regions (i.e., the "rich club") that may act as a backbone for global network integration (De Reus, Saenger, Kahn, & van den Heuvel, 2014;Mišić, Sporns, & McIntosh, 2014;Towlson, Vértes, Ahnert, Schafer, & Bullmore, 2013;Van den Heuvel, Kahn, Goñi, & Sporns, 2012). Functionally, the anatomical rich club is also hypothesized to act as a gatekeeper, modulating the dynamical interactions between lower-degree regions and the emergence of distinct functional network configurations (Senden, Deco, de Reus, Goebel, & van den Heuvel, 2014;Crossley et al, 2013).…”

The role of the structural connectome in literacy and numeracy development in children

“…This rich club is thought to be highly important for computational capacity (Senden et al 2014) and is implicated across a range of adult and developmental disorders (Crossley et al 2014). Rich club organisation is already established in the prenatal brain (Ball et al 2014) and persists over childhood (Grayson et al 2014) and adolescence into adulthood (Baker et al 2015).…”