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Fig. 1 | Translational Neurodegeneration

Fig. 1

From: Transcranial magnetic stimulation to understand pathophysiology and as potential treatment for neurodegenerative diseases

Fig. 1

Transcranial magnetic stimulation and its measurements. a When TMS is applied to the primary motor cortex, it produces descending volleys in the spinal cord. This in turn activates the spinal motoneurons and a motor-evoked potential (MEP) can be recorded in the target muscle (e.g. FDI muscle) with surface EMG. b MEP measurements. When TMS is delivered during voluntary muscle contraction, an MEP is followed by a silent period with no background EMG activity. MEP latency is defined as the time from TMS delivery to the onset of MEP. MEP amplitude is usually measured as the peak-to-peak value. Silent period can be measured from the onset or the end of MEP to the first recovery of background EMG activity. EMG = electromyogram, FDI = first dorsal interosseous, MEP = motor evoked potential, TMS = transcranial magnetic stimulation. Modified from Ni et al., Transcranial magnetic stimulation in different current directions activates separate cortical circuits, Journal of Neurophysiology 2011, 105:749-756 [8]

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