| Cortical reorganization can be found because of the brain plasticity. Previous researches suggested an expansion of the adjacent cortical representations into the cortical area representing the deafferentated body part after amputation. This may indicate the cortical area representing the missing hand involved the motor control of the lip and the stump following the amputation of upper-limb. Comparison with the normal subjects and bilateral upper-limb amputees without special foot movement skill, to study the bilateral upper limb amputees with extraordinary foot movement skill as following:â‘ fMRI of executed tapping of right toes.â‘¡fMRI of imagined tapping of right toes.â‘¢functional connectivity MRI (fcMRI) in resting-state. FMRI data showed that the cortical area representing the missing hand was activated by executed and imagined toe tapping in amputees, which wasn't found in normal subjects. Furthermore, the sensory cortex of previous hand was activated in the amputees with extraordinary foot movement skill by executed toe tapping, which was not found in amputee without special foot movement skill and normal subjects. From the resting-state fMRI date, we analysed the cross-correlation between the ROI of hand and toe by cross-correlation analyses(CCA), and indicated that the the amputees have the high cross-correlation than the normal subjects. From the executed and imagined toe tapping, we found that the cortical reorganization of amputees with extraordinary foot movement skill much higher than the amputees without special foot movement skill, which wasn't found in normals. The present study of rest fMRI revealed that the amputees have strong functional connectivity than the normal subjects. Our date suggest that after amputation the cortical reorganization is not limited to the adjacent cortex and the area representing the missing hand also controls the foot movement. And the study revealed that the cortical reorganization can be enhanced by practice in amputees.
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