Corticospinal contribution to arm muscle activity during human walking
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Corticospinal contribution to arm muscle activity during human walking. / Barthélemy, Dorothy; Nielsen, Jens Bo.
In: Journal of Physiology, Vol. 588, No. 6, 2010, p. 967-979.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Corticospinal contribution to arm muscle activity during human walking
AU - Barthélemy, Dorothy
AU - Nielsen, Jens Bo
N1 - Keywords: Adult; Arm; Electromyography; Evoked Potentials, Motor; Female; Gait; Humans; Male; Muscle Contraction; Muscle, Skeletal; Pyramidal Tracts; Transcranial Magnetic Stimulation; Walking
PY - 2010
Y1 - 2010
N2 - When we walk, our arm muscles show rhythmic activity suggesting that the central nervous system contributes to the swing of the arms. The purpose of the present study was to investigate whether corticospinal drive plays a role in the control of arm muscle activity during human walking. Motor evoked potentials (MEPs) elicited in the posterior deltoid muscle (PD) by transcranial magnetic stimulation (TMS) were modulated during the gait cycle in parallel with changes in the background EMG activity. There was no significant difference in the size of the MEPs at a comparable level of background EMG during walking and during static PD contraction. Short latency intracortical inhibition (SICI; 2 ms interval) studied by paired-pulse TMS was diminished during bursts of PD EMG activity. This could not be explained only by changes in background EMG activity and/or control MEP size, since SICI showed no correlation to the level of background EMG activity during static PD contraction. Finally, TMS at intensity below the threshold for activation of corticospinal tract fibres elicited a suppression of the PD EMG activity during walking. Since TMS at this intensity is likely to only activate intracortical inhibitory interneurones, the suppression is in all likelihood caused by removal of a corticospinal contribution to the ongoing EMG activity. The data thus suggest that the motor cortex makes an active contribution, through the corticospinal tract, to the ongoing EMG activity in arm muscles during walking.
AB - When we walk, our arm muscles show rhythmic activity suggesting that the central nervous system contributes to the swing of the arms. The purpose of the present study was to investigate whether corticospinal drive plays a role in the control of arm muscle activity during human walking. Motor evoked potentials (MEPs) elicited in the posterior deltoid muscle (PD) by transcranial magnetic stimulation (TMS) were modulated during the gait cycle in parallel with changes in the background EMG activity. There was no significant difference in the size of the MEPs at a comparable level of background EMG during walking and during static PD contraction. Short latency intracortical inhibition (SICI; 2 ms interval) studied by paired-pulse TMS was diminished during bursts of PD EMG activity. This could not be explained only by changes in background EMG activity and/or control MEP size, since SICI showed no correlation to the level of background EMG activity during static PD contraction. Finally, TMS at intensity below the threshold for activation of corticospinal tract fibres elicited a suppression of the PD EMG activity during walking. Since TMS at this intensity is likely to only activate intracortical inhibitory interneurones, the suppression is in all likelihood caused by removal of a corticospinal contribution to the ongoing EMG activity. The data thus suggest that the motor cortex makes an active contribution, through the corticospinal tract, to the ongoing EMG activity in arm muscles during walking.
U2 - 10.1113/jphysiol.2009.185520
DO - 10.1113/jphysiol.2009.185520
M3 - Journal article
C2 - 20123782
VL - 588
SP - 967
EP - 979
JO - The Journal of Physiology
JF - The Journal of Physiology
SN - 0022-3751
IS - 6
ER -
ID: 21014638