Figure 1: Hypothesized central effects PRE might have in the cortex, basal ganglia, and spinal cord and the tools that can be used to examine these hypothesized changes. TMS, transcranial magnetic stimulation; EEG, electroencephalography; fMRI, functional magnetic resonance imaging; PET: positron emission tomography; DTI: diffusion tensor imaging; EMG: electromyography; SNc: substantia nigra pars compacta; GPe: external globus pallidus; GPi: internal globus pallidus; STN: subthalamic nucleus.