Understanding the neurobiological mechanisms underlying different types of tremor and the altered functional connectivity of the involved areas is a timely goal in clinical neuroscience. If successful, this quest may open new perspectives on how to achieve tremor modulation, which is notably relevant, in Parkinson's disease (PD). Tremor can be characterized by simple parameters such as frequency and amplitude. It is therefore prone to be objectively targeted by neuromodulation and quantitatively investigated using multimodal techniques, such as, accelerometry, EMG and functional Magnetic Resonance Imaging (fMRI). Embarking on the latter challenge requires an a priori knowledge of how effective functional connectivity is altered in PD tremor. This works aims to ascertain which postural and voluntary movement tasks with distinct types of physical load are suitable for designing efficient fMRI protocols, by performing an accelerometry analysis to measure spontaneous and imposed tremor modulation on cohorts of PD patients, essential tremor patients and a group of voluntary healthy controls.