AUTHOR=Fujio Kimiya , Obata Hiroki , Kitamura Taku , Kawashima Noritaka , Nakazawa Kimitaka TITLE=Corticospinal Excitability Is Modulated as a Function of Postural Perturbation Predictability JOURNAL=Frontiers in Human Neuroscience VOLUME=12 YEAR=2018 URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2018.00068 DOI=10.3389/fnhum.2018.00068 ISSN=1662-5161 ABSTRACT=
Recent studies demonstrated that the corticospinal pathway is one of the key nodes for the feedback control of human standing and that the excitability is flexibly changed according to the current state of posture. However, it has been unclear whether this pathway is also involved in a predictive control of human standing. Here, we investigated whether the corticospinal excitability of the soleus (SOL) and tibialis anterior (TA) muscles during standing would be modulated anticipatorily when perturbation was impending. We measured the motor-evoked potential (MEP) induced by transcranial magnetic stimulation over the motor cortex at six stimulus intensities. Three experimental conditions were set depending on predictabilities about perturbation occurrence and onset: No perturbation, No Cue, and Cue conditions. In the Cue condition, an acoustic signal was given as timing information of perturbation. The slope of the stimulus–response relation curve revealed that the TA-MEP was enhanced when postural perturbation was expected compared to when the perturbation was not expected (No Perturbation vs. No Cue, 0.023 ± 0.004 vs. 0.042 ± 0.007; No Perturbation vs. Cue, 0.023 ± 0.004 vs. 0.050 ± 0.009; Bonferroni correction,