title: The lateral hypothalamus and anterior hypothalamic nucleus differentially contribute to rats' defensive responses in the elevated plus-maze and shock-probe burying tests.
abstract: Lesions or pharmacological inhibition of the lateral septum reduce rats' open-arm avoidance in the elevated plus-maze and their burying behavior in the shock-probe test. The current study examined whether hypothalamic areas that receive direct input from the lateral septum also influence open-arm avoidance and defensive burying. Bilateral infusions of the GABA-A receptor agonist muscimol (20 ng) into the lateral hypothalamus selectively increased rats' open-arm avoidance without affecting shock-probe burying. In contrast, infusions of muscimol into the anterior hypothalamic nucleus suppressed burying without affecting rats' open-arm avoidance. These dissociations suggest that the lateral hypothalamus contributes to the exploration of potentially threatening environments, whereas the anterior hypothalamus influences defensive responses to proximal discrete threat stimuli.
authors.affiliation: Centre for Neuroscience Studies, Canada.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Hakvoort Schwerdtfeger
authors.forename: Janet L
authors.initials: JL
authors.lastname: Menard
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D007025:Anterior Hypothalamic Nucleus / Q000293:injuries / Q000502:physiology*; D001362:Avoidance Learning / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects; D003674:Defense Mechanisms; D004597:Electroshock / Q000379:methods; D005106:Exploratory Behavior / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D007026:Hypothalamic Area, Lateral / Q000293:injuries / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans
chemical_list: D018755:GABA Agonists; D009118:Muscimol