title: Dendritic spine remodeling induced by hindlimb unloading in adult rat sensorimotor cortex.
abstract: A sensorimotor restriction, for instance in patients confined to bed, induces an impairment in motor function, which could be due to structural and functional reorganization of the sensorimotor cortex. Hindlimb unloading (HU) is a rodent model used to reproduce the chronic weightless bearing and reduction in hindlimb movement. In this study, we determined whether a 14-day period of HU in adult rats leads to dendritic spine plasticity. For this purpose, we visualized a large number of spines on pyramidal neurons located in superficial and deep layers of the cortex within the hindpaw representation area, by means of confocal microscopy. Spines were classified according to their shape, as stubby, thin, mushroom, or filopodium. Spine density was increased (+26%) after HU. The increase concerned mainly filopodium spines (+82%) and mushrooms (+33%), whereas no change was noticed for stubby and thin spines. Spine length was decreased, whatever their shape. Head diameter evolved differently depending on the layer: it was increased in superficial layers and decreased in deeper ones. These results indicate that morphological changes accompany functional reorganization of motor cortex in response to a decrease in sensorimotor function during adulthood.
authors.affiliation: Laboratoire Biologie Structurale Intégrée, Institut de Recherche Interdisciplinaire USR3078, CNRS, Parc scientifique 50 avenue de Halley, 59658 Villeneuve d'Ascq, France. dave.trinel@iri.univ-lille1.fr
authors.forename: Dave
authors.initials: D
authors.lastname: Trinel
authors.forename: Florence
authors.initials: F
authors.lastname: Picquet
authors.forename: Bruno
authors.initials: B
authors.lastname: Bastide
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Canu
mesh_terms: D000818:Animals; D048430:Cell Shape / Q000502:physiology; D049229:Dendritic Spines / Q000502:physiology*; D006614:Hindlimb / Q000502:physiology*; D019417:Hindlimb Suspension; D008297:Male; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology