The speed and geometry of resting state dynamic Functional Connectivity

We are happy announcing that a diptych of publications on resting dynamic Functional Connectivity is finally out on NeuroImage!

Functional Connectivity (FC) measured on resting state fMRI is dynamic and continually reconfiguring. However these variations are not necessarily very large and discrete state transitions are difficult (or questionable) to identify. Here we introduce a new paradigm in which the dynamic reconfiguration of Functional Connectivity is modeled as a smooth stochastic walk in the high-dimensional space of possible network configurations. The speed at which this stochastic exploration is not constant but is alternating between episodes of slow variation called “knots” and episodes of very strong modification called “leaps”, so that the geometry of the resulting walk is not uniformly filling the space as a Brownian motion but is rather clustered, tending to look more like a Levy-type walk.

We find ways to measure speed, its variation through time and the geometry of dynamic FC (dFC) walks. We study then how these properties of dFC walks change along aging or after 24 hours of sleep deprivation. We find that elderly subjects have slower and less structured walks of dFC reconfigurations. In addition subjects would dFC walks are faster or more structured tend to have better cognitive performance, despite age or sleep deprivation.

To know more, read:

  • Battaglia, D., Boudou, T., Hansen, E.C.A., Lombardo, D., Chettouf, S., Daffertshofer, A., Mcintosh, A.R., Zimmermann, J., Ritter, P., Jirsa, V. (2020). Dynamic Functional Connectivity between order and randomness and its evolution across the human adult lifespan. Neuroimage 222, 117156.
  • Lombardo, D., Cassé-Perrot, C., Ranjeva, J.-P., Le Troter, A., Guye, M., Wirsich, J., Payoux, P., Bartrés-Faz, D., Bordet, R., Richardson, J.C., Félician, O., Jirsa, V., Blin, O., Didic, M.* Battaglia, D.* (2020). Modular slowing of resting-state dynamic Functional Connectivity as a marker of cognitive dysfunction induced by sleep deprivation. NeuroImage 222, 117155. [* Shared last authorship].

PS: we also have a toolbox to compute our dFC random walk metrics! Check here:

  • L.M. Arbabyazd, D. Lombardo, O. Blin, M. Didic, D. Battaglia*, V. Jirsa* (2020). Dynamic Functional Connectivity as a complex random walk: Definitions and the dFCwalk toolbox. MethodsX 7, 101168. [* Shared last authorship].