Subthalamic nucleus versus pedunculopontine nucleus stimulation in Parkinson disease: synergy or antagonism?

Stimulation of the subthalamic nucleus (STN) improves the cardinal features of Parkinson disease (PD). However, its efficacy on gait disorders is less satisfying in the long term. In recent years, the pedunculopontine (PPN) nucleus has emerged as a possible promising deep brain stimulation target for gait disorders in PD.