Neurophysiological evaluation of the pedunculopontine nucleus in humans

The pedunculopontine nucleus (PPTg) is constituted by a heterogeneous cluster of neurons located in caudal mesencephalic tegmentum which projects to the thalamus to trigger thalamocortical rhythms and the brainstem to modulate muscle tone and locomotion. It has been investigated as potential deep brain stimulation (DBS) target for treating Parkinson’s disease (PD) symptoms. Neurophysiological studies conducted in humans using DBS electrodes for exploring functional properties of PPTg in vivo, reviewed in this paper, demonstrated that the functional connections between PPTg and cortex, basal ganglia, brainstem network involved in sleep/wake control, and spinal cord can be explored in vivo and provided useful insights about the physiology of this nucleus and pathophysiology of PD.