Motor priming induces changes in resting state dynamics in cerebellum of writer’s cramp dystonia: insights for clinical therapies

Background Writer’s cramp (WC) is an adult-onset focal dystonia that impairs hand and arm movements during writing tasks. Previous studies have identified abnormal resting state connectivity between the basal ganglia and cerebellum in WC. However, the role of brain state in modulating these dynamics remains poorly understood, limiting advances in clinical therapies. Objective This study investigated how a motor priming paradigm affects resting state dynamics in functional networks implicated in WC dystonia. Methods Fourteen WC participants and 20 HV underwent functional MRI (fMRI) during two resting brain states: naïve rest and rest following a motor priming paradigm (non-naïve rest). Group Independent Component Analysis was applied to isolate independent spatial components called functional networks (FNs) known to play a role in dystonia including the cerebellar, basal ganglia, sensorimotor, and superior parietal networks. The default mode network served as a control. To compare resting state brain dynamics between WC and HV, amplitude of low frequency fluctuations (ALFF) were extracted for each FN and resting state. Frequency- and state-dependent differences in ALFF were statistically assessed using general linear modeling. Results At 0.02 Hz, ALFF differences in the cerebellar network were influenced by both group identity and rest condition, with WC exhibiting decreased values during non-naïve rest, opposite to the pattern observed in HV. In contrast, at 0.10 Hz, WC showed increased ALFF values in the superior parietal network compared with HV, and this difference was independent of the motor priming paradigm. Conclusion Brain state significantly influences resting state dynamics in WC dystonia, with the cerebellar and superior parietal networks exhibiting distinct state- and frequency-dependent engagement. These findings highlight the importance of integrating motor priming paradigms with neuromodulation therapies to selectively engage key brain networks implicated in WC dystonia and potentially improve therapeutic outcomes.