title: On the Role of the Pedunculopontine Nucleus and Mesencephalic Reticular Formation in Locomotion in Nonhuman Primates.
abstract: The mesencephalic reticular formation (MRF) is formed by the pedunculopontine and cuneiform nuclei, two neuronal structures thought to be key elements in the supraspinal control of locomotion, muscle tone, waking, and REM sleep. The role of MRF has also been advocated in modulation of state of arousal leading to transition from wakefulness to sleep and it is further considered to be a main player in the pathophysiology of gait disorders seen in Parkinson's disease. However, the existence of a mesencephalic locomotor region and of an arousal center has not yet been demonstrated in primates. Here, we provide the first extensive electrophysiological mapping of the MRF using extracellular recordings at rest and during locomotion in a nonhuman primate (NHP) (Macaca fascicularis) model of bipedal locomotion. We found different neuronal populations that discharged according to a phasic or a tonic mode in response to locomotion, supporting the existence of a locomotor neuronal circuit within these MRF in behaving primates. Altogether, these data constitute the first electrophysiological characterization of a locomotor neuronal system present within the MRF in behaving NHPs under normal conditions, in accordance with several studies done in different experimental animal models.
  
  
  
  We provide the first extensive electrophysiological mapping of the two major components of the mesencephalic reticular formation (MRF), namely the pedunculopontine and cuneiform nuclei. We exploited a nonhuman primate (NHP) model of bipedal locomotion with extracellular recordings in behaving NHPs at rest and during locomotion. Different MRF neuronal groups were found to respond to locomotion, with phasic or tonic patterns of response. These data constitute the first electrophysiological evidences of a locomotor neuronal system within the MRF in behaving NHPs.
authors.affiliation: Université Grenoble Alpes, F-38000 Grenoble, France, Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France.
authors.forename: Laurent
authors.identifier: 0000-0001-5807-131X
authors.initials: L
authors.lastname: Goetz
authors.affiliation: Université Grenoble Alpes, F-38000 Grenoble, France, Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Piallat
authors.affiliation: Université Grenoble Alpes, F-38000 Grenoble, France, Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France.
authors.forename: Manik
authors.identifier: 0000-0003-1836-0007
authors.initials: M
authors.lastname: Bhattacharjee
authors.affiliation: Université Grenoble Alpes, F-38000 Grenoble, France, Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France, Unité Mixte de Service IRMaGe, Centre Hospitalier Universitaire Grenoble, Grenoble 38043, Cedex 9, France, and Unité Mixte de Service 3552, Centre National de la Recherche Scientifique, Grenoble 38043, Cedex 9, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Mathieu
authors.affiliation: Université Grenoble Alpes, F-38000 Grenoble, France, Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France.
authors.forename: Olivier
authors.identifier: 0000-0003-0776-0216
authors.initials: O
authors.lastname: David
authors.affiliation: Université Grenoble Alpes, F-38000 Grenoble, France, Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France, Department of Neurosurgery, Grenoble Alpes Hospital, Grenoble 38043, Cedex 9, France, SChabardès@chu-grenoble.fr.
authors.forename: Stéphan
authors.identifier: 0000-0002-7930-1476
authors.initials: S
authors.lastname: Chabardès
mesh_terms: D000818:Animals; D004567:Electrodes, Implanted; D055724:Electrophysiological Phenomena; D005260:Female; D008124:Locomotion / Q000502:physiology*; D008252:Macaca fascicularis; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000166:cytology / Q000502:physiology*; D008839:Microelectrodes; D009474:Neurons / Q000502:physiology; D045042:Pedunculopontine Tegmental Nucleus / Q000166:cytology / Q000502:physiology*; D011323:Primates / Q000502:physiology*; D012154:Reticular Formation / Q000166:cytology / Q000502:physiology*
keywords: locomotion; mesencephalic locomotor region; mesencephalic reticular formation; microelectrode recording; nonhuman primates; pedunculopontine nucleus