Session Information
Date: Wednesday, June 7, 2017
Session Title: Neurophysiology (Non-PD)
Session Time: 1:15pm-2:45pm
Location: Exhibit Hall C
Objective: This study aims to investigate the associative plasticity induced by cerebellum to primary motor cortex (CB–>M1) corticocortical paired associative stimulation (PAS) in patients with spinocerebellar ataxia type 3 (SCA 3).
Background: The previous study has shown that bidirectional spike-timing dependent plasticity (STDP)-like M1 plasticity can be mediated by CB–>M1 PAS, probably through the cerebello-dentato-thalamo-cortical (CDTC) pathway. Nevertheless, the nature of such plasticity remains unknown in patients with SCA3.
Methods: Nine gene-confirmed patients with SCA3 and ten healthy control subjects were studied. One hundred and twenty pairs of transcranial magnetic stimulation (TMS) of the left M1 preceded by right lateral CB TMS at an interstimulus interval of 2 ms (CB–>M1 PAS2ms) and 6 ms (CB–>M1 PAS6ms) were respectively applied with at least one week interval. M1 excitability was assessed by motor-evoked potential (MEP) amplitude, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF) and cerebellar inhibition (CBI) at the first dorsal interosseous muscle of the right hand before and after the CB–>M1 PAS.
Results: In the control group, a significant MEP potentiation was found immediately after the CB–>M1 PAS2ms protocol. In contrast, CB–>M1 PAS6ms resulted in significant suppression of the MEP amplitude. This bidirectional modulation on MEP amplitude was absent in the patients with SCA3. There was a significant impairment of SICI in the SCA3 group irrespective of the PAS protocols. CBI revealed a non-specific reduction following the CB–>M1 PAS intervention in the control group only. ICF did not show any significant change in both groups.
Conclusions: Findings suggest that CB–>M1 PAS-induced bidirectional STDP-like M1 plasticity is significantly impaired in patients with SCA3. The interpretation would be a profound functional perturbation within the CDTC circuit in the patients with SCA3.
To cite this abstract in AMA style:
M.-K. Lu, J.-C. Chen, C.-M. Chen, C.-H. Tsai. Impaired cerebellum to motor cortex associative plasticity in patients with spinocerebellar ataxia type 3 [abstract]. Mov Disord. 2017; 32 (suppl 2). https://www.mdsabstracts.org/abstract/impaired-cerebellum-to-motor-cortex-associative-plasticity-in-patients-with-spinocerebellar-ataxia-type-3/. Accessed May 15, 2025.« Back to 2017 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/impaired-cerebellum-to-motor-cortex-associative-plasticity-in-patients-with-spinocerebellar-ataxia-type-3/