title: Hypergravity within a critical period impacts on the maturation of somatosensory cortical maps and their potential for use-dependent plasticity in the adult.
abstract: We investigated experience-dependent plasticity of somatosensory maps in rat S1 cortex during early development. We analyzed both short- and long-term effects of exposure to 2G hypergravity (HG) during the first 3 postnatal weeks on forepaw representations. We also examined the potential of adult somatosensory maps for experience-dependent plasticity after early HG rearing. At postnatal day 22, HG was found to induce an enlargement of cortical zones driven by nail displacements and a contraction of skin sectors of the forepaw map. In these remaining zones serving the skin, neurons displayed expanded glabrous skin receptive fields (RFs). HG also induced a bias in the directional sensitivity of neuronal responses to nail displacement. HG-induced map changes were still found after 16 wk of housing in normogravity (NG). However, the glabrous skin RFs recorded in HG rats decreased to values similar to that of NG rats, as early as the end of the first week of housing in NG. Moreover, the expansion of the glabrous skin area and decrease in RF size normally induced in adults by an enriched environment (EE) did not occur in the HG rats, even after 16 wk of EE housing in NG. Our findings reveal that early postnatal experience critically and durably shapes S1 forepaw maps and limits their potential to be modified by novel experience in adulthood.
authors.affiliation: Neurosciences Intégratives et Adaptatives, Aix-Marseille Université, Centre National de la Recherche Scientifique, Unité Mixte Recherche 7260, Fédération de Recherches Comportement-Cerveau-Cognition 3512, Marseille, France.
authors.forename: Yoh'i
authors.initials: Y
authors.lastname: Zennou-Azogui
authors.affiliation: Neurosciences Intégratives et Adaptatives, Aix-Marseille Université, Centre National de la Recherche Scientifique, Unité Mixte Recherche 7260, Fédération de Recherches Comportement-Cerveau-Cognition 3512, Marseille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Catz
authors.affiliation: Neurosciences Intégratives et Adaptatives, Aix-Marseille Université, Centre National de la Recherche Scientifique, Unité Mixte Recherche 7260, Fédération de Recherches Comportement-Cerveau-Cognition 3512, Marseille, France christian.xerri@univ-amu.fr.
authors.forename: Christian
authors.identifier: 0000-0001-8960-9629
authors.initials: C
authors.lastname: Xerri
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D001931:Brain Mapping; D005552:Forelimb / Q000503:physiopathology; D006724:Hoof and Claw / Q000254:growth & development / Q000294:innervation / Q000503:physiopathology; D018471:Hypergravity / Q000009:adverse effects*; D008297:Male; D009434:Neural Pathways / Q000254:growth & development / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D020318:Rats, Long-Evans; D012867:Skin / Q000254:growth & development / Q000294:innervation / Q000503:physiopathology; D013003:Somatosensory Cortex / Q000254:growth & development* / Q000503:physiopathology*
keywords: cortex; critical period; development; electrophysiological mapping; forepaw