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. Author manuscript; available in PMC: 2020 Apr 1.
Published in final edited form as: Clin Neurophysiol. 2018 Nov 30;130(4):558–567. doi: 10.1016/j.clinph.2018.10.020

Figure 1. Experimental design for testing the effects of deep brain stimulation on primary motor cortex using transcranial magnetic stimulation.

Figure 1.

(A) The effects of DBS on the M1 have been tested using TMS with various experimental paradigms in movement disorders patients with DBS implanted in different basal ganglia nuclei. Common DBS targets for movement disorders including STN, GPi and Vim are labeled on the right side of the brain. The DBS electrodes (typically have four contacts in total) are usually implanted with the middle contacts located in the target nuclei. Other important basal ganglia nuclei including SN, GPe, putamen and caudate are labeled on the left side of the brain. TMS is applied to the M1 ipsilateral to the basal ganglia nucleus being tested. (B) Experimental setup. In many studies, DBS on the studied side was set at low frequency (< 10 Hz) and that on the contralateral side was turned off. TMS was triggered with DBS artifact at certain ISI. The interactions between basal ganglia nucleus and M1 were tested by measuring the changes in MEP amplitudes. DBS = deep brain stimulation, GPe = external globus pallidus, GPi = internal globus pallidus, ISI = interstimulus interval, M1 = primary motor cortex, MEP = motor evoked potential, SN = substantia nigra, STN = subthalamic nucleus, TMS = transcranial magnetic stimulation, Vim = ventralis intermedius nucleus of thalamus.