"Phase-response functions characterize directional functional connectivity of large-scale neural oscillations"

On behalf of the 'Rhythms of the Mind - From Theory to Bench and Bedside' Group, Prof. Boris Gutkin will give a talk titled "Phase-response functions characterize directional functional connectivity of large-scale neural oscillations" as part of the ongoing Student/Postdoc-Run Speaker Series (SPRSS).

Abstract: Large scale oscillations or rhythms emerge in brain structures driven by synaptic interactions within neuronal circuits. Such macroscopic rhythms have been linked to routing the flow of information across cortical regions, resulting in a what is know as the cortical functional connectome. A key  mechanism to such functional connectivity  is binding of oscillatory activity  through phase-locking. While there is experimental support for multiple phase-locking modes in the brain, the underlying mechanisms that permit macroscopic rhythms to phase lock is still debated. In this talk we show how the emergent macroscopic phase-locking can be analysed with a combination of exact reduced network approach and  weakly coupled oscillator theory. For the macroscopic activity we can derive so-called phase response functions or curves (PRCs) that show how the oscillatory system responds to transient inputs. I will then focus on a minimal set up with two cortical regions with emergent gamma oscillations, and study their interactions and the collective dynamics. Notably under conduction delays, fully symmetrically coupled networks can display symmetry-broken states of activity, where one network starts to lead in phase the second (also sometimes known as stuttering states). In these the symmetry-broken state, the effects of the incoming transient inputs depend on which network is targeted (the leader or the follower) as well as the timing of the input. Hence we show how the dynamics of the emergent phase-locked activity imposes a functional directionality on how signals are processed. Time permitting I will also discuss new results on how this approach can be extended to large-scale connectome-based brain networks.

For information on other talks organized by the 'Rhythms of the Mind - From Theory to Bench and Bedside' Student/Postdoc-Run Group, view the program overview here.