<Originals>Further Insight into Excitability Changes of Intracortical Inhibitory (ICI) and Facilitatory (ICF) Circuits in Human Hand Motor Area During Motor Imagery

概要

論文の詳細を見る
The present study was undertaken to further insight into how intracortical inhibitory (ICI) and facilitatory (ICF) circuits in human primary motor cortex are modulated during motor imagery (MI) and how both neural circuits relate with human voluntary movement. To address these questions, we used a paired-pulse transcranial magnetic stimulation technique to examine the changes of motor evoked potential (MEP) of the first dorsal interosseous muscle. The present results showed that the amounts of enhanced MEP amplitudes in both circuits during MI were not significantly different. However, the regression coefficients of ICI between with and without MI were significantly different but those of ICF were not. These results confirmed that both ICI and ICF circuits are separately controlled. Moreover, it was indicated that ICI circuits are more sensitive for internal voluntary drives than ICF circuits. In conclusion, the present findings suggest that inhibitory circuits of human motor cortex might play a dominant role for human voluntary movements. Functional implications of inhibitory circuits were also discussed in relation to movement practice.