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Influence of vestibular input on spatial and nonspatial memory and on hippocampal NMDA receptors
Author(s) -
Besnard S.,
Machado M.L.,
Vignaux G.,
Boulouard M.,
Coquerel A.,
Bouet V.,
Freret T.,
Denise P.,
LelongBoulouard V.
Publication year - 2012
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20942
Subject(s) - hippocampal formation , vestibular system , neuroscience , hippocampus , psychology , nmda receptor , spatial memory , receptor , medicine , working memory , cognition
It has recently been shown that a lack of vestibular sensory information decreases spatial memory performance and induces biochemical changes in the hippocampus in rodents. After vestibular neurectomy, patients display spatial memory deficit and hippocampal atrophy. Our objectives were to explore: (a) spatial (Y maze, radial‐arm maze), and non‐spatial (object recognition) memory performance, (b) modulation of NMDA receptors within the hippocampus using radioligand binding, and (c) hippocampal atrophy, using MRI, in a rat model of bilateral labyrinthectomy realized in two operations. Chemical vestibular lesions (VLs) were induced in 24 animals by transtympanic injections of sodium arsanilate (30 mg/0.1 ml/ear), one side being lesioned 3 weeks after the other. The control group received transtympanic saline solution (0.1 ml/ear) ( n = 24). Spatial memory performance (Y maze and radial maze) decreased after VL. Conversely, non‐spatial memory performance (object recognition) was not affected by VL. No hippocampal atrophy was observed with MRI, but density of NMDA receptors were increased in the hippocampus after VL. These findings show that the lack of vestibular information induced specific deficits in spatial memory. Additionally, quantitative autoradiographic data suggest the involvement of the glutamatergic system in spatial memory processes related to vestibular information. When studying spatial memory performances in the presence of vestibular syndrome, two‐step labyrinthectomy is a suitable procedure for distinguishing between the roles of the specific components of vestibular input loss and those of impaired locomotor activity. © 2011 Wiley Periodicals, Inc.