Deep brain stimulation
Bilateral implantation is necessary for symmetric results as well as the ability to reduce the intensity and duration of off-periods as well increase the duration of on-periods. The most effective structures used for implantations for deep brain stimulation are the internal globus pallidus (GPi) and the subthalamic nucleus (STN). This is because it is safer and more effective to alter the influence of the basal ganglia on the thalamocortical nuclei than directly altering neural activity in upper motor neuron circuits. Deep brain stimulation is a more complicated process than other therapies such as ablation. Evidence suggests that benefits of STN deep brain stimulation is due to the activation of efferents and the modulation of discharge patterns in the GPi that are propagated throughout the thalamocorical pathways. The ability to adjust stimulation protocols lends this treatment to a variety of disorders due its ability to alter the activity of basal ganglia circuits.