title: Region and task-specific activation of Arc in primary motor cortex of rats following motor skill learning.
abstract: Motor learning requires protein synthesis within the primary motor cortex (M1). Here, we show that the immediate early gene Arc/Arg3.1 is specifically induced in M1 by learning a motor skill. Arc mRNA was quantified using a fluorescent in situ hybridization assay in adult Long-Evans rats learning a skilled reaching task (SRT), in rats performing reaching-like forelimb movement without learning (ACT) and in rats that were trained in the operant but not the motor elements of the task (controls). Apart from M1, Arc expression was assessed within the rostral motor area (RMA), primary somatosensory cortex (S1), striatum (ST) and cerebellum. In SRT animals, Arc mRNA levels in M1 contralateral to the trained limb were 31% higher than ipsilateral (p<0.001), 31% higher than in the contralateral M1 of ACT animals (p<0.001) and 48% higher than in controls (p<0.001). Arc mRNA expression in SRT was positively correlated with learning success between two sessions (r=0.52; p=0.026). For RMA, S1, ST or cerebellum no significant differences in Arc mRNA expression were found between hemispheres or across behaviors. As Arc expression has been related to different forms of cellular plasticity, these findings suggest a link between M1 Arc expression and motor skill learning in rats.
authors.affiliation: Clinical Neurorehabilitation, Department of Neurology, University of Zurich, Zurich, Switzerland; Rehabilitation Initiative and Technology Center (RITZ), Zurich, Switzerland.
authors.forename: J A
authors.initials: JA
authors.lastname: Hosp
authors.forename: S
authors.initials: S
authors.lastname: Mann
authors.forename: B M
authors.initials: BM
authors.lastname: Wegenast-Braun
authors.forename: M E
authors.initials: ME
authors.lastname: Calhoun
authors.forename: A R
authors.initials: AR
authors.lastname: Luft
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002531:Cerebellum / Q000378:metabolism / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000502:physiology*; D003627:Data Interpretation, Statistical; D007839:Functional Laterality / Q000502:physiology; D017403:In Situ Hybridization; D007858:Learning / Q000502:physiology*; D008297:Male; D018613:Microscopy, Confocal; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D017072:Neostriatum / Q000378:metabolism / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D013003:Somatosensory Cortex / Q000502:physiology
chemical_list: D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; C092069:activity regulated cytoskeletal-associated protein
keywords: ACT; ANOVA; Arc; CG; DIG; EDTA; FISH; IEG; LTP; M1; ODNs; PBS; PFA; REM; RMA; ROI; SRT; TBS; TEA; activity control task; analysis of variance; cACT; cSRT; contralateral hemisphere of SRT; contralateral henisphere of ACT; control group; desoxyribonucleic acids; digoxigenin; ethylenediaminetetraacetic acid; iSRT; immediate-early gene; ipsilateral hemisphere of SRT; long-term potentiation; motor cortex; motor learning; paraformaldehyde; phosphate-buffered saline; rapid eye movement; regions of interests; rostral motor area; skilled reaching task; triethanolamine; tris-buffered saline