Task-and phase-related changes in cortico-muscular coherence
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Task-and phase-related changes in cortico-muscular coherence. / Masakado, Yoshihisa; Nielsen, Jens Bo.
In: Keio Journal of Medicine, Vol. 57, No. 1, 2008, p. 50-56.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Task-and phase-related changes in cortico-muscular coherence
AU - Masakado, Yoshihisa
AU - Nielsen, Jens Bo
N1 - CURIS 2008 5200 035
PY - 2008
Y1 - 2008
N2 - Cortico-muscular coherence was compared during ramp-and-hold isometric and quasi-isotonic contraction of the ankle joint in human subjects. EEG was recorded from the leg area of the motor cortex. EMG was recorded from the tibialis anterior (TA) muscle. The subjects were requested to maintain a steady low level of dorsiflexion and at intervals of 10 s to increase the contraction level within 1 s, maintain this level for 4 s and then decrease the level of contraction again within another 1 s. In seven subjects coherence in the 15-35 Hz frequency band was seen between EEG and TA EMG during low-level tonic dorsiflexion. In all subjects coherence disappeared during the ramp phase for both isometric and quasi-isotonic contraction. Coherence at other frequencies was also not observed in any of the subjects during the ramp phase. During the hold phase at the stronger level of contraction coherence reappeared quickly and had the same size as at the low level of contraction. However, a significantly larger level of coherence was found during quasi-isotonic than during the isometric contraction. This demonstrates that cortico-muscular coherence in the 15-35 Hz frequency band is phase- and task-related. The decrease in 15-35 Hz coherence during the ramp phase may be related to event-related desynchronization of EEG activity. The larger level of coherence during quasi-isotonic contraction may reflect a higher demand of precise control of the joint position. It may also reflect a greater need for binding of functionally related cortical pyramidal tract neurons.
AB - Cortico-muscular coherence was compared during ramp-and-hold isometric and quasi-isotonic contraction of the ankle joint in human subjects. EEG was recorded from the leg area of the motor cortex. EMG was recorded from the tibialis anterior (TA) muscle. The subjects were requested to maintain a steady low level of dorsiflexion and at intervals of 10 s to increase the contraction level within 1 s, maintain this level for 4 s and then decrease the level of contraction again within another 1 s. In seven subjects coherence in the 15-35 Hz frequency band was seen between EEG and TA EMG during low-level tonic dorsiflexion. In all subjects coherence disappeared during the ramp phase for both isometric and quasi-isotonic contraction. Coherence at other frequencies was also not observed in any of the subjects during the ramp phase. During the hold phase at the stronger level of contraction coherence reappeared quickly and had the same size as at the low level of contraction. However, a significantly larger level of coherence was found during quasi-isotonic than during the isometric contraction. This demonstrates that cortico-muscular coherence in the 15-35 Hz frequency band is phase- and task-related. The decrease in 15-35 Hz coherence during the ramp phase may be related to event-related desynchronization of EEG activity. The larger level of coherence during quasi-isotonic contraction may reflect a higher demand of precise control of the joint position. It may also reflect a greater need for binding of functionally related cortical pyramidal tract neurons.
U2 - 10.2302/kjm.57.50
DO - 10.2302/kjm.57.50
M3 - Journal article
C2 - 18382125
VL - 57
SP - 50
EP - 56
JO - Keio Journal of Medicine
JF - Keio Journal of Medicine
SN - 0022-9717
IS - 1
ER -
ID: 3608887