Role of the rostral dorsomedial column of the periaqueductal gray during social defeat in rats

Author(s)

de Almeida, Alisson Pinto ; Tamais, Alicia Moraes ; Zerbini, Carolina ; Melleu, Fernando Falkenburger ; Canteras, Newton Sabino ; Motta, Simone Cristina

• Document type: Journal article
• Source: Annals of the New York Academy of Sciences; v. 1530, n. 1, p. 14-pg., 2023-10-11.

Abstract

Previous studies showed that the dorsal premammillary nucleus of the hypothalamus (PMD) is involved in social passive defensive behaviors likely to be meditated by descending projections to the periaqueductal gray (PAG). We focused on the rostral dorsomedial PAG (rPAGdm) to reveal its putative neural mechanisms involved in mediating social defensive responses. By combining retrograde tracing and FOS expression analysis, we showed that in addition to the PMD, the rPAGdm is influenced by several brain sites active during social defeat. Next, we found that cytotoxic lesions of the rPAGdm drastically reduced passive defense and did not affect active defensive responses. We then examined the rPAGdm's projection pattern and found that the PAGdm projections are mostly restricted to midbrain sites, including the precommissural nucleus, different columns of the PAG, and the cuneiform nucleus (CUN). Also, we found decreased FOS expression in the caudal PAGdm, CUN, and PMD after the rPAGdm was lesioned. The results support that the rPAGdm mediates passive social defensive responses through ascending paths to prosencephalic circuits likely mediated by the CUN. This study provides further support for the role of the PAG in the modulation of behavioral responses by working as a unique hub for influencing prosencephalic sites during the mediation of aversive responses. Previous studies showed that the dorsal pre-mammillary nucleus of the hypothalamus is involved in social passive defensive behaviors likely to be meditated by descending projections to the periaqueductal gray (PAG). We focused on the rostral dorsomedial PAG to reveal its putative neural mechanisms involved in mediating social defensive responses. #image (AU)

• FAPESP's process: 10/05905-3 - Neuroendocrine and autonomic responses in rats with dorsal premammilary nucleus lesion after social defeat
• Grantee: Simone Cristina Motta
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/05413-8 - The functional contributions of the dorsal premammillary nucleus of the hypothalamus on C57Bl/6 mice's social defense behavior.
• Grantee: Carolina Zerbini
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 22/07530-4 - Role of the medial amygdala nucleus in the re-exposure to social defeat
• Grantee: Alicia Moraes Tamais
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 21/02864-9 - The role of the juxtadorsomedial region of the lateral hypothalamus in processing environment cues associated with social defeat
• Grantee: Alisson Pinto de Almeida
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 16/18667-0 - Manipulating the neural circuit underlying social defense
• Grantee: Simone Cristina Motta
• Support Opportunities: Research Grants - Young Investigators Grants