Category: Parkinson's Disease: Neurophysiology
Objective: To investigate the interaction between subthalamic nucleus (STN), dorsal premotor (PMd), and primary motor cortex (M1) in patients with Parkinson’s disease (PD) in vivo by coupling low frequency deep brain stimulation (DBS) of the STN with PMd-M1 dual-pulse transcranial magnetic stimulation (TMS) and correlating effects with volume of tissue activated (VTA) of STN DBS.
Background: PMd-M1 interaction has been shown to be abnormal in PD. DBS of the STN is an efficient treatment in advanced PD. However, its influence on PMd-M1 interaction is not yet understood.
Method: 19 PD patients (4 females, age 60.5 ± 2.3 years [mean ± standard error of mean ) with STN DBS were examined with dual-pulse TMS at lowest (3 Hz) and highest (20 Hz) DBS frequencies technically possible to trigger TMS by using surface electrodes above the impulse generator to detect DBS artefacts. STN DBS preceded PMd-M1 TMS at specific intervals. PMd-M1 interstimulus intervals (ISIs) of 1, 4 and 6 ms and STN-M1 ISIs of 3, 10, 22, 26 ms were used. As control condition, a maximum STN-M1 ISI (323 ms at 3 Hz and 40 ms at 20 Hz) was chosen. Repeated measures ANOVAs as well as post hoc testing using Student’s t-test with Bonferroni-Holm correction were performed. VTA was calculated by identifying the electrode locations in the MRI and using the LEAD DBS toolbox. STN-VTA was correlated with the STN effect on PMd-M1 interaction using Pearson correlation.
Results: We found the PMd-M1 inhibitory conditioning effect to be ISI specific (F(2,36)=8.244, p<0.001). Post hoc test revealed a difference between ISI of 1 ms and 6 ms, indicating PMd-M1 inhibition at 1 ms. STN conditioning (F(1,18)=7.589, p=0.013) reduced PMd-M1 inhibitory conditioning. This STN effect had no influence on M1 excitability (F(3,54)=0.243, p=0.866) nor specific for DBS frequency (F(1,18)=0.283, p=0.601). The effect of the STN on PMd-M1 interaction correlated positively with the VTA for PMd-M1 ISI of 1 ms (r=0.660; p=0.030, Bonferroni-Holm corrected).
Conclusion: STN stimulation affects PMd-M1 interaction by reducing the inhibition, especially at a PMd-M1 ISI of 1 ms. This suggests a monosynaptic interaction between PMd and M1. The effect of STN on PMd-M1 increased in patients with larger STN VTA.
To cite this abstract in AMA style:M. Pauly, M. Barlage, F. Hamami, J. Steinhardt, J. Baarbe, S. Tran, H. Hanssen, V. Tadic, N. Brueggemann, R. Chen, A. Muenchau, T. Baeumer, A. Weissbach. Influence of deep brain stimulation on premotor-motor interaction in patients with Parkinson’s disease [abstract]. Mov Disord. 2021; 36 (suppl 1). https://www.mdsabstracts.org/abstract/influence-of-deep-brain-stimulation-on-premotor-motor-interaction-in-patients-with-parkinsons-disease/. Accessed December 1, 2023.
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MDS Abstracts - https://www.mdsabstracts.org/abstract/influence-of-deep-brain-stimulation-on-premotor-motor-interaction-in-patients-with-parkinsons-disease/