Rhythm Perception and Generation

Objective Rhythmic movements, such as finger tapping, are relatively simple. However, many brain areas including motor, somatosensory, premotor and prefrontal cortex, supplementary motor area, basal ganglia, cerebellum, etc. have been reported to be activated during rhythmic movements. Patients with lesions located in the extrapyramidal or cerebellar system, such as patients with Parkinson's disease, cerebellar ataxia or stroke with a lesion in these systems, have difficulties in performing rhythmic movements. Timing deficits after basal ganglia or cerebellar damage could also be due to abnormalities in interconnecting cortical systems commonly associated with these processes. Few studies have examined involvement of cerebral cortex in time perception. The purpose of this study is to detect the brain areas associated with three hypothesized processes associated with rhythm perception and generation: (1) perception of external rhythmic stimulation, (2) internal rhythm generation and (3) execution of rhythmic movement. To investigate whether the process of rhythm perception is common across sensory modalities, we will use auditory and visual stimulation. Study population This research will be conducted using normal adult volunteers. Design Using functional magnetic resonance imaging, we will examine the brain activity of subjects while they will hear or watch rhythmic stimulation and press buttons rhythmically with their fingers. A series of experiments will be designed to demonstrate the hypothesized three processes separately. Outcome measures The brain activity correlated with experimental conditions and behavioral data (the timing error of button press to the corresponding rhythmic stimulation) will be collected and analyzed by using statistical parametric mapping (SPM). The findings we expect to obtain with this experiment will contribute to basic knowledge for better understanding of the pathophysiology of the disturbance of perception and generation of rhythm in patients with neurological disorders, and give theoretical background for repetitive, rhythmically patterned movement training in neurorehabilitation.