Integrating effective and functional connectivity shows disrupted oscillatory and causal dynamics in multiple sclerosis

Motivation: Functional connectivity depends on brain oscillations providing a statistical indirect evaluation of the underlying neuronal activity. Goal(s): We aim at integrating functional connectivity with effective connectivity, which directly measures neuronal activity driving causal relations between brain regions. Approach: We used spectral Dynamic Causal Modeling to derive the effective connectivity, and assessed its relation with functional connectivity in healthy participants and multiple sclerosis patients. Results: The coupling between effective and functional connectivity revealed an inverted correlation in motor and visual-to-motor pathways between groups. In healthy participants, information flow was causal-driven, whereas it shifted to oscillation-driven dynamics in multiple sclerosis. Impact: Integrating effective and functional connectivity detects shifts between causal-driven and oscillation-driven dynamics in physiological and pathological conditions. This novel approach offers an opportunity to develop rehabilitation protocols based on the interplay between neuronal activity and brain oscillations.