Altered network connectivity and global efficiency in tourette syndrome: insights into sensorimotor integration

This study investigates the role of theta connectivity in network mechanisms related to perception-action-binding, sensorimotor integration, and motor preparation in children with Tourette's Syndrome (TS). High-density EEG data were collected from 21 children with drug-naïve TS and 21 age-matched healthy controls during a task combining an informative warning stimulus (S1) with a behaviorally relevant imperative stimulus (S2). Event-related phase synchronization and global efficiency were calculated to analyze stimulus processing and identify neural networks responsible for integrating sensory information with motor preparation processes. Results revealed widespread alterations in theta-band connectivity in TS, with patients exhibiting reduced connectivity and impaired network efficiency during S1 processing. S2 processing revealed subtler group differences than S1, manifesting as shifts in network organization rather than overall loss in connectivity strength. Remarkably, global efficiency during S2 processing remained intact in the TS group. In both groups, higher global efficiency during S2 correlated with faster reaction times, highlighting a direct link between network efficiency and motor response speed. This suggests that, despite altered sensory processing during information integration of the warning stimulus, motor execution mechanisms remain preserved in TS. The reduced connectivity during S1 processing may represent a compensatory mechanism aimed at weakening perception-action binding, potentially preventing premature motor output and aiding in tic control. These findings support the view of TS as a network disorder extending beyond traditional cortico-striato-thalamo-cortical circuits and suggest potential targets for interventions to modulate network efficiency and compensatory mechanisms in TS.