2007 Fiscal Year Final Research Report Summary
Functional role of mirror neuron system on human movement
Project/Area Number |
18500510
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Sports science
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Research Institution | Hiroshima University |
Principal Investigator |
FUNASE Kozo Hiroshima University, Graduate School of Integrated Arts and Sciences, Professor (40173512)
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Co-Investigator(Kenkyū-buntansha) |
TABIRA Takayuki Nagasaki University, Graduate School of Biomedical Sciences, Assistant Professor (50337432)
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Project Period (FY) |
2006 – 2007
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Keywords | Mirror Neuron System / Human Movement / Transcranial Magnetic Stimulation / Observation and Imitation / Motor Imagery |
Research Abstract |
In this study, functional role of mirror neuron system on human movement was investigated in the following experiments. (1) To explore the effect of mirror box (MB) therapy based on the mirror neuron system (MNS) of the primary motor cortex, we examined if direct (without a mirror) and indirect (with a mirror) observation of self-movement in healthy subjects induced changes in motor evoked potential (MEP) evoked by transcranial magnetic stimulation (TMS). MEPs were elicited from the first dorsal interosseous (FDI) and the flexor carpi radialis (FCR) muscles. Somatosensory evoked potentials (SEPs) during self-movement observation were also recorded. Both observations of self-movement with and without a mirror increased MEP amplitude. The SEPs increased similar to the MEPs during both observations of self-movement with and without a mirror. We conclude that although the MN system can be activated by observing self-movement in a manner similar to that achieved by observing movement of anot
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her person, there were no detectable effect on corticospinal excitability that were specific to movements observed with a mirror. (2) We investigated the effect of reading tasks at different vocal volumes on the excitability of hand motor cortex assessed by TMS-induced MEP in both right- and left-handed subjects. TMSs were applied to both hand motor cortices, respectively, and MEPs were recorded from both FDI muscles in all subjects. As a result, we found the bilateral facilitation of the hand motor cortices during the reading task at vocal volume in the normal conversations irrespective of subject's dominant hand. Weak activation of the jaw muscle comparable with the reading task did not affect the excitability of hand motor cortices of the bilateral hemispheres. This means that the activation of the oral motor cortex and the activation of the jaw muscle afferents hardly contribute to the excitability of hand motor cortex during the reading task. Furthermore, observation for video clip of another person's reading task also induced the bilateral facilitation of hand motor cortices. Increased excitability of left hand motor cortex compared to that of right motor cortex was confirmed during the reading loud task in the right-handed subjects only, as previously reported. Findings suggest the reading-induced bilateral facilitation of hand motor cortices which may be caused by the activation of MNS. Further, we discussed the relation to bimanual band gesture often observed in conversations in daily life. (3) Effect of video clip observation in which a person plays 3 balls cascade on the excitability of band motor cortex assessed by TMS-induced MEP. MEPswere recorded from FDI and opponens pollicis (OP) muscle. Experimental conditions were, 1) motor imagery with video clip observation (real), 2) motor imagery with video clip observation in which a person plays 3 balls cascade without balls (fake) and 3) self motor imagery for 3 balls cascade. The most enhancements of MEPs in both FDI and OP were found in real condition. Degrees of enhancement were ordered in self and then fake condition. These results suggest that the video clip observation of such a complex and difficult action help to make motor imagery rather than self motor imagery for that. Interestingly, fake action does not have much effect to make motor imagery. This result well corresponds to the previous studies which show the properties of MNS. Less
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Research Products
(26 results)