Bilateral Motor Cortex Control for Left Thumb Movement: An Incidental Finding Through Functional MRI (fMRI)

We report a case of a healthy, right-hand dominant young male who was a volunteer for a pilot run of a functional MRI (fMRI) study. The fMRI was performed with a 3.0 Tesla MRI scanner using a finger tapping task-based activity. The subjects were instructed to perform flexion of the right thumb and left thumb consecutively (activation task) and neuronal activation in bilateral primary motor cortex (PMC) were observed during each task. One particular subject demonstrated bilateral PMC activation during the left-thumb movement task, instead of the expected activation of the contralateral PMC alone.