Functional Brain Mapping Of Voluntary Movement And The Impact Of Learning

Functional anatomy of voluntary movements, particulary in the humans, is far from well understood. The present study of a series of experiments with functional MRI aimed to address several fundamental questions: whether the neual networks for motor preparation and execution are distinct or overlapped; whether voluntary movements are associated with unilateral or bilateral brain structures; how short-term transient practice and long-term professional training modify brain activiti associated with motor preparation and execution; whether the cerebellum is involved in motor learning.Part â… Objective To investigate the brain regions engaged during sequential movements and functional laterality of these regions. Methods: we employed a functional magnetic resonance imaging(fMRI) combined with right hand sequential finger movement task to investigate brain activation pattern and laterality in 8 subjects. 3dDeconvolve program of AFNI was used to estimate the hemodynamic response function and to generate activation maps. Then the laterality index (LI) was calculated and tested statistically. Results: Sequential movements elicited activation in primary motor area (M1), supplementary motor area (SMA) and posterior parietal cortex (PPC), premotor cortex (PMC), cingulate gyrus, and sucortical structures including basal ganglia and cerebellum. While Ml, SMA and PPC showed left lateralization and cerebellum right lateraliztion, no significant lateraliztion was found in PMC, cingulate gyrus, , and basal gangliaConclusions: Sequential movements depend on a large network involving a number of cortical and subcortical regions. Most of them showed lateralilzation with left-lateraliztion (countralateral to the movement hand) in the regions of cerebral cortex and right-lateralization (ipsilateral to the movement hand) in the cerebellum.Objective: To characterize the distribution of preparation- and execution-related activity in the cerebral cortex. Methods: Seven right-handed healthy subjects performed a delayed sequential movement task, in which prepare signal indicated the movement sequence prior to the appearance of an imperative execution signal. AFNI software were used to analyze the data. Results: Conventional activation analysis demonstrated that contralateral primary motor cortex (Ml), and bilateral premotor cortex, supplementary motor area (SMA) and parietal cortex were significantly activated during execution, whereas only anterior SMA (pre-SMA), bilateral anterior premotor cortex (PMC) and posterior parietal cortex (PPC) were significantly activated during preparation. However, further analysis of difference in response intensity between preparation and execution revealed a gradient distribution of these activities in bilateral SMA, contralateral frontal and parietal cortex. The area nearer to Ml showed more execution related activation. Conclusions: The boundaries of motor associated regions seem not to be as clear as previously demonstrated. Most motor-associated regions could be regarded as well-organized sub-systems rather homogeneous functional units in motor control.Part â…¢Objective: To investigate brain activation pattern and laterality during a transient practice. Methods: An event-related functional magnetic resonance imaging combined with a delayed sequential movement task was engaged in 12 subjects. The same sequence was scanned for three times. The first and the third results were compared. Results: Both hemispheres, involving bilateral motor areas and posterior parietal cortex, were activated during motor preparation and execution, with weak left lateralization. Activation volume in these regions significantly decreased after a transient practice, with more reduction in the right hemisphere resulting increase in left lateralization. Conclusions: Short term practice can result in changes of brain activation and function laterality.Part IVObjective: To examine whether the cerebellum is involved in voluntary motor learning or motor performance Methods: Using functional magnetic resonance imaging, we examined cerebella...