title: Evidence for a role of the reticulospinal system in recovery of skilled reaching after cortical stroke: initial results from a model of ischemic cortical injury.
abstract: The purposes of this pilot study were to create a model of focal cortical ischemia in Macaca fascicularis and to explore contributions of the reticulospinal system in recovery of reaching. Endothelin-1 was used to create a focal lesion in the shoulder/elbow representation of left primary motor cortex (M1) of two adult female macaques. Repetitive microstimulation was used to map upper limb motor outputs from right and left cortical motor areas and from the pontomedullary reticular formation (PMRF). In subject 1 with a small lesion and spontaneous recovery, reaching was mildly impaired. Changes were evident in the shoulder/elbow representations of both the lesioned and contralesional M1, and there appeared to be fewer than expected upper limb responses from the left (ipsilesional) PMRF. In subject 2 with a substantial lesion, reaching was severely impaired immediately after the lesion. After 12 weeks of intensive rehabilitative training, reach performance recovered to near-baseline levels, but movement times remained about 50% slower. Surprisingly, the shoulder/elbow representation in the lesioned M1 remained completely absent after recovery, and there was a little change in the contralesional M1. There was a definite difference in motor output patterns for left versus right PMRF for this subject, with an increase in right arm responses from right PMRF and a paucity of left arm responses from left PMRF. The results are consistent with increased reliance on PMRF motor outputs for recovery of voluntary upper limb motor control after significant cortical ischemic injury.
authors.affiliation: Division of Physical Therapy, School of Health and Rehabilitation Sciences,, The Ohio State University, 453 W. 10th Ave., Rm. 516G, Columbus, OH, 43210-1234, USA.|Health and Rehabilitation Sciences PhD Program, The Ohio State University, Columbus, OH, 43210, USA.|Department of Physical Therapy Education, Elon University, Campus Box 2085, Elon, NC, 27244, USA.
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Herbert
authors.affiliation: Small Animal Imaging Core, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, 43210, USA.
authors.forename: Kimerly
authors.initials: K
authors.lastname: Powell
authors.affiliation: Division of Physical Therapy, School of Health and Rehabilitation Sciences,, The Ohio State University, 453 W. 10th Ave., Rm. 516G, Columbus, OH, 43210-1234, USA. Buford.5@osu.edu.|Health and Rehabilitation Sciences PhD Program, The Ohio State University, Columbus, OH, 43210, USA. Buford.5@osu.edu.|Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH, 43210, USA. Buford.5@osu.edu.
authors.forename: John A
authors.initials: JA
authors.lastname: Buford
mesh_terms: D000344:Afferent Pathways; D000818:Animals; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology* / Q000534:rehabilitation; D004195:Disease Models, Animal; D004558:Electric Stimulation; D019332:Endothelin-1 / Q000633:toxicity; D005260:Female; D007839:Functional Laterality; D008252:Macaca fascicularis; D009044:Motor Cortex / Q000293:injuries / Q000473:pathology* / Q000502:physiology; D019957:Motor Skills Disorders / Q000209:etiology*; D010865:Pilot Projects; D020127:Recovery of Function / Q000502:physiology*; D012154:Reticular Formation / Q000473:pathology / Q000503:physiopathology*; D013116:Spinal Cord / Q000473:pathology / Q000503:physiopathology*; D034941:Upper Extremity / Q000503:physiopathology
chemical_list: D019332:Endothelin-1
keywords: Hemiparesis; Stroke; Upper extremity