Measuring the Contralateral Silent Period Induced by Transcranial Magnetic Stimulation

In This Article

Abstract

Source: Rebello-Sanchez, I., et al. Measuring Contralateral Silent Period Induced by Single-Pulse Transcranial Magnetic Stimulation to Investigate M1 Corticospinal Inhibition. J. Vis. Exp. (2022).

This video demonstrates a technique for measuring the contralateral silent period (cSP) using transcranial magnetic stimulation. Position the patient's hand prone and place an electrode on the first dorsal interosseous (FDI) muscle. Then, place a force-measuring device between the thumb and index finger. Identify the primary motor cortex (M1) region of the brain. Maintain a standardized pressure on the force-measuring device and stimulate the M1 region to record the muscle activity, termed the motor-evoked potential (MEP), followed by the subsequent period of reduced muscle activity, termed cSP.

Protocol

All procedures involving human participants have been performed in compliance with the institutional, national, and international guidelines for human welfare and have been reviewed by the local institutional review board.

1. Experimental procedures (Figure 1)

Select the muscle for positioning the electrodes.
1. Ask the subject to put their hand over the table, in a prone position. Select the FDI muscle, localized between the first and second metacarpal osseous. To identify the FDI, ask the subject to abduct their index finger against resistance, keeping the rest of the hand still and laying on the tabl....

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Results

Transcranial magnetic stimulation (TMS) experimental protocol diagram depicting motor cortex activity.
Figure 1: Experimental steps. 1. Electrode placement on the belly of the FDI muscle 2. Positioning of the dynamometer between fingers. 3. Voluntary contraction of the target muscle to test the standardization of 20% MVC 4. Head measurements and TMS pu.......