title: Different corticospinal control between discrete and rhythmic movement of the ankle.
abstract: We investigated differences in corticospinal and spinal control between discrete and rhythmic ankle movements. Motor evoked potentials (MEPs) in the tibialis anterior and soleus muscles and soleus H-reflex were elicited in the middle of the plantar flexion phase during discrete ankle movement or in the initial or later cycles of rhythmic ankle movement. The H-reflex was evoked at an intensity eliciting a small M-wave and MEPs were elicited at an intensity of 1.2 times the motor threshold of the soleus MEPs. Only trials in which background EMG level, ankle angle, and ankle velocity were similar among the movement conditions were included for data analysis. In addition, only trials with a similar M-wave were included for data analysis in the experiment evoking H-reflexes. Results showed that H reflex and MEP amplitudes in the soleus muscle during discrete movement were not significantly different from those during rhythmic movement. MEP amplitude in the tibialis anterior muscle during the later cycles of rhythmic movement was significantly larger than that during the initial cycle of the rhythmic movement or during discrete movement. Higher corticospinal excitability in the tibialis anterior muscle during the later cycles of rhythmic movement may reflect changes in corticospinal control from the initial cycle to the later cycles of rhythmic movement.
authors.affiliation: Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University Habikino, Japan.
authors.forename: Yumeno
authors.initials: Y
authors.lastname: Goto
authors.affiliation: Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University Habikino, Japan.
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Jono
authors.affiliation: Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University Habikino, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Hatanaka
authors.affiliation: Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University Habikino, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Nomura
authors.affiliation: Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University Habikino, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tani
authors.affiliation: Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University Habikino, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Chujo
authors.affiliation: College of Health and Human Sciences, Osaka Prefecture University Habikino, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hiraoka
keywords: H-Reflex; central pattern generator; corticospinal excitability; discrete movement; motor evoked potential; rhythmic movement