Effects of postnatal interference of vestibular GABA transmission on navigation behavior in adult rats

Abstract

Although spatial navigation is predominantly guided by allothetic visual cues, idiothetic cues can obtain control when familiar visual cues are not available. In path integration, the current position and orientation are estimated and continuously updated using idiothetic cues, which are contributed by the vestibular system. Previous studies have revealed that vestibular lesioned rats were significantly impaired in path integration. Rats assessed in the current study received neonatal treatment with either VU0240551 (KCC2 blocker) or muscimol (GABAA receptors agonist) in the vestibular nuclei. Path integration ability appears to be intact in rats receiving either treatment. However, VU0240551-treated rats displayed impairments in their ability to resolve conflicting allothetic and idiothetic cues. Therefore, it is proposed that the ability to properly resolve a cue-conflict requires the normal polarity of GABA and/or glycine action in the vestibular nuclei during the neonatal period.