It seems possible that stimulating the PPN could elicit positive motor effects and inhibiting it would lead to akinesia. We stereotactically implanted a macroelectrode in the unilateral PPN region in a normal macaque to investigate the effects of chronic electrical stimulation at different frequencies. At 100 Hz there was gross impairment of postural control. All these effects were quickly reversible and there was neither impairment of alertness nor limb weakness. We conclude that the effects of stimulation of the PPN are frequency dependent.
Activity counts with stimulation at different frequencies.