The relationship between mirror movement and corticomuscular coherence.

Shin Murata, Kotaro Nakagawa, Shoya Fujikawa, Ryosuke Yamamoto, Naoki Shimizu, Takato Nishida, Yusuke Shizuka, Shun Sawai, Hideki Nakano
Purpose:

This study aimed to examine the relationship between mirror movement and corticomuscular coherence with respect to the left and right motor cortex, and to clarify the involvement of both hemispheres in mirror movement.

Methods:

Thirty-six healthy young adults performed a complex hand task in which they rotated two marbles in their right hand. Electroencephalography was measured from the left and right motor cortex, and electromyography was measured from the left and right flexor digitorum superficialis muscles. The degree of mirror movement was defined as the change rate of the root mean square of the electroencephalography of the left flexor digitorum superficialis muscle during the task from rest. The coherence value in the γ frequency band between each electrode was calculated from the electromyogram and electroencephalogram data during the task. The correlation between degree of mirror movement and coherence value was analyzed to verify corticomuscular coherence related to mirror movement. The statistical significance level was set at 5%.

Results:

A significant positive correlation was found between the degree of mirror movement and the corticomuscular coherence of the right motor cortex and the right flexor digitorum superficialis muscles (ρ = 0.37, p = 0.03). On the other hand, a significant negative correlation was found between the degree of mirror movement and the corticomuscular coherence of the left motor cortex and the left flexor digitorum superficialis muscles (ρ = -0.43, p 0.01). These results indicate that the higher the mirror movement, the higher the functional connectivity between the voluntary hand and its ipsilateral motor cortex, and the lower the functional connectivity between the involuntary hand and its ipsilateral motor cortex. This also suggests that the ipsilateral corticospinal tract is involved in mirror movement.

Conclusion(s):

In this study, it’s found that mirror movements relate to ipsilateral corticomuscular coherence on both of voluntary and involuntary sides. Thus, this study reveals one of the neural bases of mirror movement.

Implications:

The results of this study indicate that the CMC of the muscle and ipsilateral motor cortex may be used as a new neurophysiological measure of mirror movement in physiotherapy evaluation.

Funding acknowledgements:
This work was supported by JSPS KAKENHI Grant Numbers JP23K10417, JP23K19907, JP24K23764.
Keywords:
Corticomuscular coherence
Mirror movement
Ipsilateral corticospinal tract
Primary topic:
Neurology
Second topic:
Basic science including molecular and cellular health
Did this work require ethics approval?:
Yes
Name the institution and ethics committee that approved your work:
The Institutional Ethics Committee of Kyoto Tachibana University
Provide the ethics approval number:
23-17
Has any of this material been/due to be published or presented at another national or international conference prior to the World Physiotherapy Congress 2025?:
No

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