Dissecting the brain's fear systems responding to snake threats.

Autor: Melleu FF; Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil., de Oliveira AR; Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil., Grego KF; Laboratory of Herpetology, Butantan Institute, São Paulo, SP, Brazil., Blanchard DC; Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.; Pacific Biosciences Research Centre, University of Hawaii at Manoa, Honolulu, Hawaii, USA., Canteras NS; Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Jazyk: angličtina
Zdroj: The European journal of neuroscience [Eur J Neurosci] 2022 Sep; Vol. 56 (6), pp. 4788-4802. Date of Electronic Publication: 2022 Aug 24.
DOI: 10.1111/ejn.15794
Abstrakt: We examined the behavioural responses and Fos expression pattern of rats that were exposed to snake threats from shed snakeskin and a live snake. We differentiated the behavioural responses and the pattern of Fos expression in response to the odour cues and mild threat from a live snake. Animals exposed to the snake odour alone or to the confined snake showed a great deal of risk assessment. Conversely, the intensification of odour during exposure to the live snake decreased the threat ambiguity, and the animals froze for a significantly longer period. Our Fos analysis showed that a pathway formed by the posteroventral part of the medial amygdalar nucleus to the central part of the ventromedial hypothalamic nucleus appeared to be solely responsive to odour cues. In addition, we showed increased Fos expression in a parallel circuit comprising the lateral amygdalar nucleus, ventral subiculum, lateral septum, and juxtadorsomedial region of the lateral hypothalamic area that is responsive to both the odour and mild threat from a live snake. This path is likely to process the environmental boundaries of the threat to be avoided. Both paths merge into the dorsal premammillary nucleus and periaqueductal grey sites, which all increase Fos expression in response to the snake threats and are likely to organize the defensive responses. Moreover, we found that the snake threat mobilized the Edinger-Westphal and supraoculomotor nuclei, which are involved in stress adaptation and attentional mechanisms.
(© 2022 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)
Databáze: MEDLINE
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