Imperial College London

Dr Shin-Yi Chiou (Chloe)

Faculty of MedicineDepartment of Surgery & Cancer

Honorary Research Associate



+44 (0)20 3313 8833s.chiou12




7L16Lab BlockCharing Cross Campus






BibTex format

author = {Chiou, S-Y and Wang, R-Y and Liao, K-K and Yang, Y-R},
doi = {10.1371/journal.pone.0072231},
journal = {PLOS One},
title = {Homologous Muscle Contraction during Unilateral Movement Does Not Show a Dominant Effect on Leg Representation of the Ipsilateral Primary Motor Cortex},
url = {},
volume = {8},
year = {2013}

RIS format (EndNote, RefMan)

AB - Co-activation of homo- and heterotopic representations in the primary motor cortex (M1) ipsilateral to a unilateral motor task has been observed in neuroimaging studies. Further analysis showed that the ipsilateral M1 is involved in motor execution along with the contralateral M1 in humans. Additionally, transcranial magnetic stimulation (TMS) studies have revealed that the size of the co-activation in the ipsilateral M1 has a muscle-dominant effect in the upper limbs, with a prominent decline of inhibition within the ipsilateral M1 occurring when a homologous muscle contracts. However, the homologous muscle-dominant effect in the ipsilateral M1 is less clear in the lower limbs. The present study investigates the response of corticospinal output and intracortical inhibition in the leg representation of the ipsilateral M1 during a unilateral motor task, with homo- or heterogeneous muscles. We assessed functional changes within the ipsilateral M1 and in corticospinal outputs associated with different contracting muscles in 15 right-handed healthy subjects. Motor tasks were performed with the right-side limb, including movements of the upper and lower limbs. TMS paradigms were measured, consisting of short-interval intracortical inhibition (SICI) and recruitment curves (RCs) of motor evoked potentials (MEPs) in the right M1, and responses were recorded from the left rectus femoris (RF) and left tibialis anterior (TA) muscles. TMS results showed that significant declines in SICI and prominent increases in MEPs of the left TA and left RF during unilateral movements. Cortical activations were associated with the muscles contracting during the movements. The present data demonstrate that activation of the ipsilateral M1 on leg representation could be increased during unilateral movement. However, no homologous muscle-dominant effect was evident in the leg muscles. The results may reflect that functional coupling of bilateral leg muscles is a reciprocal movement.
AU - Chiou,S-Y
AU - Wang,R-Y
AU - Liao,K-K
AU - Yang,Y-R
DO - 10.1371/journal.pone.0072231
PY - 2013///
SN - 1932-6203
TI - Homologous Muscle Contraction during Unilateral Movement Does Not Show a Dominant Effect on Leg Representation of the Ipsilateral Primary Motor Cortex
T2 - PLOS One
UR -
UR -
VL - 8
ER -