Frequency-specific equivalence of brain activity on motor imagery during action observation and action execution

Abstract

Background

Human motor imagery (MI), action execution, and action observation (AO) are functionally considered as equivalent. MI during AO can extensively induce activation of motor-related brain network in the absence of overt movement. The magnetoencephalography (MEG) provides an important technology to reveal and reflect human brain information processing in multi-frequency bands. Utilizing a MEG system, we aimed to quantitatively investigate the frequency-specific equivalent characteristics in brain processing patterns between MI during AO and action execution in multi-frequency bands, including delta, theta, alpha, beta, gamma, and high-frequency oscillations.

Methods

A total of 12 healthy subjects were studied with a whole-head MEG system during finger movement and MI during finger movement observation. We analyzed the brain activities in multi-frequency ranges of 1 Hz to 200 Hz.

Results

Both MI during AO and action execution evoked the distinctive brain activities in low frequency ranges (i.e. delta, theta, and alpha). Significant differences were found in global spectral power between finger movement and MI during AO in delta and alpha oscillations. Compared with finger movement, delta (1–4 Hz) oscillation power in MI during AO were obviously decreased in left and right frontals and occipitals, and theta (4–8 Hz) and alpha (8–13 Hz) oscillation power were obviously increased in frontal, parietal and occipital.

Conclusion

MEG power evoked by finger movement and MI during AO is mainly concentrated in the energy distribution below 13 Hz. Furthermore, finger movement and MI during AO might share frequency-specific equivalence of brain neural activation dependent on different MEG frequency ranges.

Keywords:

• Brain activity
• multi-frequency MEG
• action observation
• motor imagery
• action execution

Disclosure statement

The authors declare no competing financial interests.

Additional information

Funding

This study was supported by the grant from the National Natural Science Foundation of China (No. 81972350), the clinical medical scientific and technologic project of National Health and Family Planning Commission of the People's Republic of China (No.w201308), the Nanjing Commission of Health and Family Planning (No. H201540), the grant from the medical scientific and technologic development project of Nanjing (No. YKK12137, ZKX15035, and ZKX14044), and the Innovation team project of 13th Five Year Plan of the Jiangsu provincial Health and Family Planning Commission (No. CXTDA2017050), and Jiangsu Government Scholarship for Overseas Studies (No. JS-2014-294).