title: Chasing central nervous system plasticity: the brainstem's contribution to locomotor recovery in rats with spinal cord injury.
abstract: Anatomical plasticity such as fibre growth and the formation of new connections in the cortex and spinal cord is one known mechanism mediating functional recovery after damage to the central nervous system. Little is known about anatomical plasticity in the brainstem, which contains key locomotor regions. We compared changes of the spinal projection pattern of the major descending systems following a cervical unilateral spinal cord hemisection in adult rats. As in humans (Brown-Séquard syndrome), this type of injury resulted in a permanent loss of fine motor control of the ipsilesional fore- and hindlimb, but for basic locomotor functions substantial recovery was observed. Antero- and retrograde tracings revealed spontaneous changes in spinal projections originating from the reticular formation, in particular from the contralesional gigantocellular reticular nucleus: more reticulospinal fibres from the intact hemicord crossed the spinal midline at cervical and lumbar levels. The intact-side rubrospinal tract showed a statistically not significant tendency towards an increased number of midline crossings after injury. In contrast, the corticospinal and the vestibulospinal tract, as well as serotonergic projections, showed little or no side-switching in this lesion paradigm. Spinal adaptations were accompanied by modifications at higher levels of control including side-switching of the input to the gigantocellular reticular nuclei from the mesencephalic locomotor region. Electrolytic microlesioning of one or both gigantocellular reticular nuclei in behaviourally recovered rats led to the reappearance of the impairments observed acutely after the initial injury showing that anatomical plasticity in defined brainstem motor networks contributes significantly to functional recovery after injury of the central nervous system.
authors.affiliation: 1 Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091 Zurich, Switzerland bjoern.zoerner@usz.ch.
authors.forename: Björn
authors.initials: B
authors.lastname: Zörner
authors.affiliation: 2 Brain Research Institute, University of Zurich and Department of Health Sciences and Technology, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Lukas C
authors.initials: LC
authors.lastname: Bachmann
authors.affiliation: 1 Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091 Zurich, Switzerland.
authors.forename: Linard
authors.initials: L
authors.lastname: Filli
authors.affiliation: 1 Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091 Zurich, Switzerland.
authors.forename: Sandra
authors.initials: S
authors.lastname: Kapitza
authors.affiliation: 2 Brain Research Institute, University of Zurich and Department of Health Sciences and Technology, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Miriam
authors.initials: M
authors.lastname: Gullo
authors.affiliation: 3 Spinal Cord Injury Centre, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Bolliger
authors.affiliation: 3 Spinal Cord Injury Centre, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Starkey
authors.affiliation: 2 Brain Research Institute, University of Zurich and Department of Health Sciences and Technology, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Martina
authors.initials: M
authors.lastname: Röthlisberger
authors.affiliation: 1 Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091 Zurich, Switzerland.
authors.forename: Roman R
authors.initials: RR
authors.lastname: Gonzenbach
authors.affiliation: 2 Brain Research Institute, University of Zurich and Department of Health Sciences and Technology, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Martin E
authors.initials: ME
authors.lastname: Schwab
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D008124:Locomotion / Q000502:physiology*; D009416:Nerve Regeneration / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D051381:Rats; D020127:Recovery of Function / Q000502:physiology; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology*
keywords: brainstem; functional recovery; plasticity; spinal cord injury