Opposite effects of one session of 1 Hz rTMS on functional connectivity between pre-supplementary motor area and putamen depending on the dyskinesia state in Parkinson's disease

Objective: To explore the effects of low-frequency repetitive transcranial magnetic stimulation (LF rTMS) on cortico-striatal-cerebellar resting state functional connectivity in Parkinson's disease (PD), with and without dyskinesias. Methods: Because there is increasing evidence of an involvement of the pre-supplementary motor area (pre-SMA) in the pathophysiology of levodopa induced dyskinesias, we targeted the right pre-SMA with LF rTMS in 17 PD patients. We explored the effects of one sham-controlled LF rTMS session on resting state functional connectivity of interconnected brain regions by using functional MRI, and how it is mod-ified by levodopa. The clinical effect on motor function and dyskinesias was documented. Results: As expected, one LF rTMS session did not alleviate dyskinesias. However, real, and not sham LF rTMS significantly increased the functional connectivity with the right putamen in patients with dyski-nesias. In patients without dyskinesias, the real LF rTMS session significantly decreased functional con-nectivity in the right putamen and the cerebellum. We found no effects on functional connectivity after levodopa ingestion. Conclusion: One session of 1 Hz rTMS has opposing effects on pre-SMA functional connectivity depending on the PD patients' dyskinesia state. Significance: Patients dyskinesias state determines the way LF rTMS affects functional connectivity in late stage PD.

Automated summary

This study investigated the effects of LF rTMS on cortico-striatal-cerebellar resting state functional connectivity in Parkinson's disease patients, and found that the effects of LF rTMS varied depending on the presence of dyskinesias in the patients.