Sleep induced by stimulation in the human pedunculopontine nucleus area.

The pedunculopontine nucleus is part of the reticular ascending arousal system and is involved in locomotion and sleep. Two patients with Parkinson disease received electrodes that stimulated the pedunculopontine nucleus area to alleviate their severe gait impairment. Instead, we found that low-frequency stimulation of the pedunculopontine nucleus area increased alertness, whereas high-frequency stimulation induced non-rapid eye movement sleep. In addition, the sudden withdrawal of the low-frequency stimulation was consistently followed by rapid eye movement sleep episodes in 1 patient. These data have the potential to benefit patients who suffer from sleep disorders.