Angelo Insola1, Luca Padua2, Paolo Mazzone3, Eugenio Scarnati4, Massimiliano Valeriani5. 1. Unità Operativa di Neurofisiopatologia, CTO, Via S. Nemesio 21, 00145 Rome, Italy. Electronic address: angelo.insola@virgilio.it. 2. Istituto di Neurologia, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Don Carlo Gnocchi Onlus, Milan, Italy. 3. Unità Operativa di Neurochirurgia funzionale e stereotassica, CTO, Via S. Nemesio 21, 00145 Rome, Italy. 4. Dipartimento di Scienze Cliniche e Biotecnologiche Applicate, Università dell'Aquila, L'Aquila, Italy. 5. Divisione di Neurologia, Ospedale Pediatrico Bambino Gesù, IRCCS, Roma, Italy; Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark.
Abstract
OBJECTIVE: To investigate the generators of the somatosensory evoked potential (SEP) components recorded from the Pedunculopontine Tegmental nucleus (PPTg). METHODS: Twenty-two patients, suffering from Parkinson's disease (PD), underwent electrode implantation in the PPTg area for deep brain stimulation (DBS). SEPs were recorded from the DBS electrode contacts to median nerve stimulation. RESULTS: SEPs recorded from the PPTg electrode contacts could be classified in 3 types, according to their waveforms. (1) The biphasic potential showed a positive peak (P16) whose latency (16.05 ± 0.61 ms) shifted of 0.18 ± 0.07 ms from the lower to the upper contact of the electrode. (2) The triphasic potential showed an initial positive peak (P15) whose latency (15.4 ± 0.2 ms) did not change across the DBS electrode contacts. (3) In the last SEP configuration (mixed biphasic and triphasic waveform), the positive peak was bifid including both the P15 and P16 potentials. CONCLUSION: While the P16 potential is probably generated by the somatosensory volley travelling along the medial lemniscus, the P15 response represents a far-field potential probably generated at the cuneate nucleus level. SIGNIFICANCE: Our results show the physiological meaning of the somatosensory responses recorded from the PPTg nucleus area.
OBJECTIVE: To investigate the generators of the somatosensory evoked potential (SEP) components recorded from the Pedunculopontine Tegmental nucleus (PPTg). METHODS: Twenty-two patients, suffering from Parkinson's disease (PD), underwent electrode implantation in the PPTg area for deep brain stimulation (DBS). SEPs were recorded from the DBS electrode contacts to median nerve stimulation. RESULTS: SEPs recorded from the PPTg electrode contacts could be classified in 3 types, according to their waveforms. (1) The biphasic potential showed a positive peak (P16) whose latency (16.05 ± 0.61 ms) shifted of 0.18 ± 0.07 ms from the lower to the upper contact of the electrode. (2) The triphasic potential showed an initial positive peak (P15) whose latency (15.4 ± 0.2 ms) did not change across the DBS electrode contacts. (3) In the last SEP configuration (mixed biphasic and triphasic waveform), the positive peak was bifid including both the P15 and P16 potentials. CONCLUSION: While the P16 potential is probably generated by the somatosensory volley travelling along the medial lemniscus, the P15 response represents a far-field potential probably generated at the cuneate nucleus level. SIGNIFICANCE: Our results show the physiological meaning of the somatosensory responses recorded from the PPTg nucleus area.
Authors: Clement Hamani; Andres M Lozano; Paolo A M Mazzone; Elena Moro; William Hutchison; Peter A Silburn; Ludvic Zrinzo; Mesbah Alam; Laurent Goetz; Erlick Pereira; Anand Rughani; Wesley Thevathasan; Tipu Aziz; Bastiaan R Bloem; Peter Brown; Stephan Chabardes; Terry Coyne; Kelly Foote; Edgar Garcia-Rill; Etienne C Hirsch; Michael S Okun; Joachim K Krauss Journal: Stereotact Funct Neurosurg Date: 2016-10-12 Impact factor: 1.875