Therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) are extensively studied in patients with Parkinson's disease (PD). rTMS to primary motor cortex (M1) induces dopamine release in the putamen: consequently M1 is an interesting target for rTMS in PD. The rTMS over M1 in PD patients reduces the reaction time, improves the Unified Parkinson's Disease Rating Scale (UPDRS) scores and alleviates bradykinesia and hypokinesia. However, the effects of rTMS on spontaneous brain activity are not known. We investigated whether subthreshold rTMS to M1 modulated spontaneous oscillations recorded with magnetoencephalography (MEG). MEG from nine medicated, non-demented PD patients displayed a significant increase in beta oscillations after rTMS in the stimulated hemisphere. Minimum current estimate calculations revealed an increase of beta oscillatory activity after the rTMS treatment over the Rolandic regions. The rTMS in PD patients alters spontaneous brain activity as seen with MEG, probably by modulating cortico-thalamo-basal ganglia networks.
- Parkinson's disease
- Spontaneous oscillations
- Transcranial magnetic stimulation