TY - JOUR
T1 - Real-time changes in corticospinal excitability related to motor imagery of a force control task
AU - Tatemoto, Tsuyoshi
AU - Tsuchiya, Junko
AU - Numata, Atsuki
AU - Osawa, Ryuji
AU - Yamaguchi, Tomofumi
AU - Tanabe, Shigeo
AU - Kondo, Kunitsugu
AU - Otaka, Yohei
AU - Sugawara, Kenichi
PY - 2017
Y1 - 2017
N2 - Objective To investigate real-time excitability changes in corticospinal pathways related to motor imagery in a changing force control task, using transcranial magnetic stimulation (TMS). Methods Ten healthy volunteers learnt to control the contractile force of isometric right wrist dorsiflexion in order to track an on-screen sine wave form. Participants performed the trained task 40 times with actual muscle contraction in order to construct the motor image. They were then instructed to execute the task without actual muscle contraction, but by imagining contraction of the right wrist in dorsiflexion. Motor evoked potentials (MEPs), induced by TMS in the right extensor carpi radialis muscle (ECR) and flexor carpi radialis muscle (FCR), were measured during motor imagery. MEPs were induced at five time points: prior to imagery, during the gradual generation of the imaged wrist dorsiflexion (Increasing phase), the peak value of the sine wave, during the gradual reduction (Decreasing phase), and after completion of the task. The MEP ratio, as the ratio of imaged MEPs to resting-state, was compared between pre- and post-training at each time point. Results In the ECR muscle, the MEP ratio significantly increased during the Increasing phase and at the peak force of dorsiflexion imagery after training. Moreover, the MEP ratio was significantly greater in the Increasing phase than in the Decreasing phase. In the FCR, there were no significant consistent changes. Conclusion Corticospinal excitability during motor imagery in an isometric contraction task was modulated in relation to the phase of force control after image construction.
AB - Objective To investigate real-time excitability changes in corticospinal pathways related to motor imagery in a changing force control task, using transcranial magnetic stimulation (TMS). Methods Ten healthy volunteers learnt to control the contractile force of isometric right wrist dorsiflexion in order to track an on-screen sine wave form. Participants performed the trained task 40 times with actual muscle contraction in order to construct the motor image. They were then instructed to execute the task without actual muscle contraction, but by imagining contraction of the right wrist in dorsiflexion. Motor evoked potentials (MEPs), induced by TMS in the right extensor carpi radialis muscle (ECR) and flexor carpi radialis muscle (FCR), were measured during motor imagery. MEPs were induced at five time points: prior to imagery, during the gradual generation of the imaged wrist dorsiflexion (Increasing phase), the peak value of the sine wave, during the gradual reduction (Decreasing phase), and after completion of the task. The MEP ratio, as the ratio of imaged MEPs to resting-state, was compared between pre- and post-training at each time point. Results In the ECR muscle, the MEP ratio significantly increased during the Increasing phase and at the peak force of dorsiflexion imagery after training. Moreover, the MEP ratio was significantly greater in the Increasing phase than in the Decreasing phase. In the FCR, there were no significant consistent changes. Conclusion Corticospinal excitability during motor imagery in an isometric contraction task was modulated in relation to the phase of force control after image construction.
KW - Agonist muscle
KW - Motor evoked potential
KW - Motor imagery
KW - Phasic force control
KW - Tracking task
KW - Transcranial magnetic stimulation
U2 - 10.1016/j.bbr.2017.08.020
DO - 10.1016/j.bbr.2017.08.020
M3 - Journal article
C2 - 28827129
AN - SCOPUS:85028069521
SN - 0166-4328
VL - 335
SP - 185
EP - 190
JO - Behavioural Brain Research
JF - Behavioural Brain Research
ER -