Abstract
Objective: To study the effect of visual feedback gain on movement with the whole-brain functional magnetic resonance imaging (fMRI). Methods: Fifteen healthy volunteers were recruited to execute a grasping task with right hand, and two force track tasks with different increasing/decreasing force rate were performed. The activated areas were evaluated with BOLD fMRI, and functional responses were established by students group t test analysis. Results: All four different grasping tasks could activate the primary somatosensory cortex (SMC), bilateral pre-motor area (PMC), supplementary motor area (SMA), cerebellum, basal ganglia (BG), the contralateral posterior parietal cortex (PPC), etc. With the increase of feedback-dependent BOLD signal, both the size and the intensity decreased in S1, PPC, PMC and cerebellum, while the activation of BG was opposite. The intensity of the active area in SMA swelled while the extent decreased, and no significant difference was found in the M1. Conclusion: Visual stimuli can influence force output significantly and different visual feedback gains may recruit different cortex function areas to execute different motor tasks. PPC, PMC, cerebellum and BG participate in regulating the power of the hand grasp with different gains.