Physiological identification of the human pedunculopontine nucleus
- Shoichi A Shimamoto1,
- Paul S Larson1,
- Jill L Ostrem2,
- Graham A Glass2,
- Robert S Turner3,
- Philip A Starr1,*
- 1 Department of Neurological Surgery, University of California, United States;
- 2 Department of Neurology, University of California, United States;
- 3 Department of Neurobiology and Center for the Neural Basis of Cognition, University of Pittsburgh, United States
- Correspondence to: Philip A Starr, University Hospital, University of California, San Francisco, 533 Parnassus Ave, box 0445, San Francisco, 94143, United States; starrp{at}neurosurg.ucsf.edu
- Received 26 March 2009
- Accepted 22 June 2009
- Published Online First 14 October 2009
Abstract
Background: The pedunculopontine nucleus (PPN) is a brainstem structure with widespread connections to the basal ganglia. Despite the recent introduction of PPN deep brain stimulation (DBS) for the treatment of gait disorders, little is known about its physiology in humans.
Methods: We analyzed single unit discharge characteristics of neurons in the PPN region in four patients and PPN local field potentials (LFP) in one patient, recorded during the course of DBS implantation. Two patients had Parkinson’s disease and two had non-sinemet responsive parkinsonism. Cell locations were plotted in the coordinate system of a human brainstem atlas.
Results: Fifty-six units in the PPN region were studied, of which 32 mapped to within PPN boundaries. The mean (+/- SD) discharge rate of neurons in the PPN was 23.2 (+/- 15.6) Hz. Spontaneous neuronal firing rate and burst discharge rate were significantly different between neurons in the region dorsal to PPN and those in the PPN. Responses to passive movement of contralateral and ipsilateral limbs were found. Theta and beta band oscillations were present in the PPN LFP.
Conclusion: PPN discharge characteristics may prove useful in the electrophysiologic identification of PPN during DBS implantation surgery.
