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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A role for the anteromedial thalamic nucleus in the acquisition of contextual fear memory to predatory threats

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Author(s):
Xavier de Lima, Miguel Antonio ; Baldo, Marcus Vinicius C. ; Canteras, Newton Sabino
Total Authors: 3
Document type: Journal article
Source: Brain Structure & Function; v. 222, n. 1, p. 113-129, JAN 2017.
Web of Science Citations: 8
Abstract

Previous studies from our group have shown that cytotoxic lesions in the ventral portion of the anteromedial thalamic nucleus (AMv), one of the main targets of the hypothalamic predator-responsive circuit, strongly impairs contextual fear responses to an environment previously associated with a predator. The AMv is in a position to convey information to cortico-hippocampal-amygdalar circuits involved in the processing of fear memory. However, it remains to be determined whether the nucleus is involved in the acquisition or subsequent expression of contextual fear. In the present investigation, we addressed this question by inactivating the rat AMv with muscimol either prior to cat exposure or prior to exposure to the cat-related context. Accordingly, AMv pharmacological inactivation prior to cat exposure did not interfere with innate fear responses, but it drastically reduced contextual conditioning to the predator-associated environment. On the other hand, AMv inactivation prior to exposure to the environment associated with the predator threat did not affect contextual fear responses. The behavioral results were further supported by the demonstration that AMv inactivation prior to cat exposure also blocked the activation of sites critically involved in the expression of anti-predatory contextual defensive responses (i.e., the dorsal premammillary nucleus and the dorsolateral periaqueductal gray) in animals exposed to the predator-associated context. The AMv projections were also examined, and the results of this investigation outline important paths that can influence hippocampal circuitry and raise new ideas for anterior thalamic-hippocampal paths involved in emotional learning. (AU)

FAPESP's process: 14/05432-9 - Neural bases of fear and aggression
Grantee:Newton Sabino Canteras
Support type: Research Projects - Thematic Grants
FAPESP's process: 13/04802-4 - Study of the cortical circuitry involved in contextual fear processing to predatory threat
Grantee:Miguel Antonio Xavier de Lima
Support type: Scholarships in Brazil - Doctorate (Direct)