title: Severe reduction of rat defensive behavior to a predator by discrete hypothalamic chemical lesions.
abstract: Nonspecific lesion and stimulation methods have suggested that the hypothalamus is critical for the expression of defensive behavior, although the organization of neural circuits mediating such behavior is unclear. In the rat hypothalamus, we found that increased Fos levels were restricted to specific cell groups following presentation of a stimulus (predator) known to elicit partly innate defensive responses. The dorsal premammillary nucleus showed the most striking increase in Fos levels, and cell body-specific chemical lesions therein virtually eliminated two major components of defensive behavior but increased exploratory behavior, suggesting that this caudal hypothalamic nucleus plays a critical role in the expression of behavioral responses sometimes critical for survival of the individual. We have previously shown that the Fos-responsive cell groups in the medial hypothalamus are interconnected in a neural system distinct from those mediating reproductive and ingestive behaviors.
authors.affiliation: Department of Physiology & Biophysics, University of São Paulo, Brazil.
authors.forename: N S
authors.initials: NS
authors.lastname: Canteras
authors.forename: S
authors.initials: S
authors.lastname: Chiavegatto
authors.forename: L E
authors.initials: LE
authors.lastname: Ribeiro do Valle
authors.forename: L W
authors.initials: LW
authors.lastname: Swanson
mesh_terms: D000818:Animals; D002415:Cats; D003714:Denervation; D004924:Escape Reaction / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists; D005239:Fear / Q000502:physiology*; D007051:Ibotenic Acid; D008297:Male; D008326:Mammillary Bodies / Q000737:chemistry / Q000503:physiopathology*; D009042:Motivation; D011235:Predatory Behavior; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D012726:Sexual Behavior, Animal / Q000502:physiology
chemical_list: D018690:Excitatory Amino Acid Agonists; D016760:Proto-Oncogene Proteins c-fos; D007051:Ibotenic Acid