The most relevant human brain regions for functional connectivity: Evidence for a dynamical workspace of binding nodes from whole-brain computational modelling

Abstract

In order to promote survival through flexible cognition and goal-directed behaviour, the brain has to optimize segregation and integration of information into coherent, distributed dynamical states. Certain organizational features of the brain have been proposed to be essential to facilitate cognitive flexibility, especially hub regions in the so-called rich club which show dense interconnectivity. These structural hubs have been suggested to be vital for integration and segregation of information. Yet, this has not been evaluated in terms of resulting functional temporal dynamics. A complementary measure covering the temporal aspects of functional connectivity could thus bring new insights into a more complete picture of the integrative nature of brain networks. Here, we use causal whole-brain computational modelling to determine the functional dynamical significance of the rich club and compare this to a new measure of the most functionally relevant brain regions for binding information over time ("dynamical workspace of binding nodes"). We found that removal of the iteratively generated workspace of binding nodes impacts significantly more on measures of integration and encoding of information capability than the removal of the rich club regions. While the rich club procedure produced almost half of the binding nodes, the remaining nodes have low degree yet still play a significant role in the workspace essential for binding information over time and as such goes beyond a description of the structural backbone.

Reliable local dynamics in the brain across sessions are revealed by whole‐brain modeling of resting state activity

“…Under a cognitive perspective, this makes sense as primary sensory information might be processed in similar ways across individuals. Finally, we found regions such as the hippocampus and the middle occipital gyrus that exhibited high consistency for one hemisphere but low in the other (Figure a) and that interestingly were in concordance with previous studies (Deco, Van Hartevelt, et al, ). These asymmetric profiles and other consistency considerations should be addressed carefully in future studies.…”

“…Furthermore, the left superior orbitofrontal cortex was by far the most consistent of all regions, with a between-subject mean error four times larger than the within-subject mean error. This is interesting given that recently this region was described as one of the most important for maintaining brain dynamical organization (Deco, Van Hartevelt, et al, 2017).…”

“…Additionally, both precuneus and thalamus also showed high level of consistency in both hemispheres, suggesting that highly centralized cores (Deco, Van Hartevelt, et al, 2017;van den Heuvel & Sporns, 2011) might also be the ones reflecting higher consistency levels. This was corroborated after exploring the consistency (from Figure 6a) of the rich and binding club members (listed in Deco, Van Hartevelt, et al, 2017) where we found that 66% of the (8/12 nodes) rich club while 41% (5/12) of the binding club exhibited high consistency levels (Supporting Information Figure S3).…”

Revisiting the Global Workspace: Orchestration of the functional hierarchical organisation of the human brain

“…Traditionally, whole-brain models have been relatively successful in linking structural connectivity with functional dynamics (Breakspear, 2017;Deco and Kringelbach, 2014). This has revealed important new mechanistic principles of brain function (Deco et al, 2018;Deco et al, 2019a;Deco et al, 2019b;Deco et al, 2017e;Honey et al, 2007). Nevertheless, the present causal characterisation of whole-brain information flow offers a new avenue for generating even more useful models.…”

Task‐related effective connectivity reveals that the cortical rich club gates cortex‐wide communication

“…These regions, collectively termed the rich club, have been hypothesized to form a central high‐capacity backbone for brain communication (van den Heuvel, Kahn, Goñi, & Sporns, ). As such they could play a crucial role in the integration of segregated brain regions into transient functional networks assumed to underlie higher cognition (Baars, ; Deco, Jirsa, & McIntosh, ; Deco, Van Hartevelt, Fernandes, Stevner, & Kringelbach, ; Dehaene & Naccache, ; Ghosh et al, ).…”