OBJECTIVE: Long-term potentiation (LTP)-like plasticity induced by paired associative stimulation (PAS) is impaired in Parkinson's disease (PD). Intermittent theta burst stimulation (iTBS) is another rTMS protocol that produces LTP-like effects and increases cortical excitability but its effects are independent of afferent input. The aim of the present study was to examine the effects of iTBS on cortical excitability in PD. METHODS: iTBS was applied to the motor cortex in 10 healthy subjects and 12 PD patients ON and OFF dopaminergic medications. Motor evoked potential (MEP) before and for 60 min after iTBS were used to examine the changes in cortical excitability induced by iTBS. Paired-pulse TMS was used to test whether intracortical circuits, including short interval intracortical inhibition, intracortical facilitation, short and long latency afferent inhibition, were modulated by iTBS. RESULTS: After iTBS, the control, PD ON and OFF groups had similar increases in MEP amplitude compared to baseline over the course of 60 min. Changes in intracortical circuits induced by iTBS were also similar for the different groups. CONCLUSIONS: iTBS produced similar effects on cortical excitability for PD patients and controls. SIGNIFICANCE: Spike-timing dependent heterosynaptic LTP-like plasticity induced by PAS may be more impaired in PD than frequency dependent homosynaptic LTP-like plasticity induced by iTBS.
OBJECTIVE: Long-term potentiation (LTP)-like plasticity induced by paired associative stimulation (PAS) is impaired in Parkinson's disease (PD). Intermittent theta burst stimulation (iTBS) is another rTMS protocol that produces LTP-like effects and increases cortical excitability but its effects are independent of afferent input. The aim of the present study was to examine the effects of iTBS on cortical excitability in PD. METHODS:iTBS was applied to the motor cortex in 10 healthy subjects and 12 PDpatients ON and OFF dopaminergic medications. Motor evoked potential (MEP) before and for 60 min after iTBS were used to examine the changes in cortical excitability induced by iTBS. Paired-pulse TMS was used to test whether intracortical circuits, including short interval intracortical inhibition, intracortical facilitation, short and long latency afferent inhibition, were modulated by iTBS. RESULTS: After iTBS, the control, PD ON and OFF groups had similar increases in MEP amplitude compared to baseline over the course of 60 min. Changes in intracortical circuits induced by iTBS were also similar for the different groups. CONCLUSIONS:iTBS produced similar effects on cortical excitability for PDpatients and controls. SIGNIFICANCE: Spike-timing dependent heterosynaptic LTP-like plasticity induced by PAS may be more impaired in PD than frequency dependent homosynaptic LTP-like plasticity induced by iTBS.
Authors: Tim Vanbellingen; Manuela Wapp; Katharina Stegmayer; Manuel Bertschi; Eugenio Abela; Stefanie Kübel; Thomas Nyffeler; René Müri; Sebastian Walther; Tobias Nef; Mark Hallett; Stephan Bohlhalter Journal: J Neural Transm (Vienna) Date: 2016-09-12 Impact factor: 3.575
Authors: Michael J Asmussen; Mark F Jacobs; Kevin G H Lee; Christopher M Zapallow; Aimee J Nelson Journal: PLoS One Date: 2013-04-04 Impact factor: 3.240