Differentiation of motor evoked potentials elicited from multiple forearm muscles: an investigation with high-density surface electromyography.

Differentiation of motor evoked potentials elicited from multiple forearm muscles: an investigation with high-density surface electromyography.
Brain Res. 2017 Sep 18;:
Authors: Neva JL, Gallina A, Peters S, Garland SJ, Boyd LA
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive method to measure corticospinal excitability of the primary motor cortex. However, motor evoked potentials (MEPs) elicited by TMS in a target muscle are variable; inconsistent MEPs may be due to overlapping cortical muscle representations and/or volume conduction from neighbouring muscles. The source of variable muscle responses may not be apparent using conventional bipolar electromyography (EMG), particularly over areas with several distinct neighbouring muscles (e.g. the forearm). High-density surface EMG (HDsEMG) may provide a useful means to investigate the underlying variability in amplitude and spatial distribution of MEPs. Here, we investigated the spatial distribution of MEPs in the forearm extensors using HDsEMG. HDsEMG consisted of a 16x5 grid of surface electrodes placed on the right (dominant) dorsal forearm over the extensor carpi radialis (ECR), ulnaris (ECU) and extensor digitorum communis finger extensors (EDC). MEP amplitude and distribution were recorded from 100-170% of resting (RMT) and active motor threshold (AMT). The distribution of MEPs was correlated to the activity recorded during selective, isometric contractions of ...

Source: Brain Research - September 18, 2017 Category: Neurology Authors: Neva JL, Gallina A, Peters S, Garland SJ, Boyd LA Tags: Brain Res Source Type: research