Under normal conditions, motor cortex areas (primary motor cortex, pre-motor cortex and supplementary motor area) are responsible for selecting the range of movements in a given action sequence, in accordance with the demands of the task and environmental restrictions, and after the onset of movements brought about by the motor cortex, the basal nuclei continue execution, leaving the motor cortex free for other tasks that require attention. However, in Parkinson's disease, automaticity promoted by basal nuclei is compromised and constant conscious control becomes necessary during gait. Thus, when an activity concurrent with this function is performed, the frontal regions become dedicated to the secondary task and gait is predominantly controlled by defective basal nuclei, which generates negative Dual Task interference on gait.