Agonist-Antagonist Coactivation Enhances Corticomotor Excitability of Ankle Muscles.

Agonist-Antagonist Coactivation Enhances Corticomotor Excitability of Ankle Muscles. Neural Plast. 2019;2019:5190671 Authors: Kesar TM, Tan A, Eicholtz S, Baker K, Xu J, Anderson JT, Wolf SL, Borich MR Abstract Spinal pathways underlying reciprocal flexion-extension contractions have been well characterized, but the extent to which cortically evoked motor-evoked potentials (MEPs) are influenced by antagonist muscle activation remains unclear. A majority of studies using transcranial magnetic stimulation- (TMS-) evoked MEPs to evaluate the excitability of the corticospinal pathway focus on upper extremity muscles. Due to functional and neural control differences between lower and upper limb muscles, there is a need to evaluate methodological factors influencing TMS-evoked MEPs specifically in lower limb musculature. If and to what extent the activation of the nontargeted muscles, such as antagonists, affects TMS-evoked MEPs is poorly understood, and such gaps in our knowledge may limit the rigor and reproducibility of TMS studies. Here, we evaluated the effect of the activation state of the antagonist muscle on TMS-evoked MEPs obtained from the target (agonist) ankle muscle for both tibialis anterior (TA) and soleus muscles. Fourteen able-bodied participants (11 females, age: 26.1 ± 4.1 years) completed one experimental session; data from 12 individuals were included in the analysis. TMS was delivered during 4 conditions: rest, TA ac...
Source: Neural Plasticity - Category: Neurology Authors: Tags: Neural Plast Source Type: research