An amygdala circuit that suppresses social engagement

Abstract

Innate social behaviors, such as mating and fighting, are fundamental to animal reproduction and survival. However, social engagements can also put an individual at risk. Little is known about the neural mechanisms that allow for appropriate risk assessment and the suppression of hazardous social interactions. We have identified the posteromedial nucleus of the cortical amygdala (COApm) as a locus required for the suppression of male mating when a female is sick. Using anatomical tracing, functional imaging, and circuit-level epistatic analyses, we show that suppression of mating with an unhealthy female is mediated by the COApm projections onto the glutamatergic population of the medial amygdalar nucleus (MEA). We further show that the role of the COApm to MEA connection in regulating male mating behavior relies on the neuromodulator thyrotropin-releasing hormone (TRH). TRH is expressed in the COApm while

Amygdala substructure volumes in Major Depressive Disorder

“…Preclinical data suggests that chronic stress may induce divergent changes in amygdala and hippocampal volumes, with enlargement of amygdala regions and reduction of hippocampal regions, largely through alterations in dendritic remodelling ( Blugeot et al, 2011 , Lakshminarasimhan and Chattarji, 2012 , Mitra et al, 2005 , Roozendaal et al, 2009 , Vyas et al, 2002 , Vyas et al, 2004 ). In our cohort of MDD participants, we also found divergent changes in amygdala and hippocampal volumes, as evidenced by smaller hippocampal substructures bilaterally, but more pronounced on the left ( Roddy et al, 2019 ) and the present finding of larger right medial amygdala nuclei, known to modulate complex social behaviours in rodents ( Hu et al, 2021 , Kwon et al, 2021 , Shemesh et al, 2016 ). We acknowledge the association between amygdala substructural volumes and phase and duration of illness, however in our MDD group these associations did not survive correction for multiple comparisons (Table S5a, b).…”

“…An anxiety-generating circuit from the central amygdala to CRH-secreting neurons in the dorsolateral stria terminalis has been identified in animal studies ( Kalin et al, 2016 , Kovner et al, 2020 , Pomrenze et al, 2019 ) and the central amygdala is involved in social and non-social threat processing ( Andraka et al, 2021 ). The medial amygdala is also implicated in complex social behaviors ( Hu et al, 2021 , Kwon et al, 2021 , Shemesh et al, 2016 ). Similar to the hippocampus, glucocorticoid receptors are expressed in the amygdala ( Wang et al, 2014 ) but, in contrast to the hippocampal feedback, amygdalar drive promotes hypothalamic CRH secretion ( Herman et al, 2016 , Myers et al, 2012 ), mainly mediated by centromedial nuclei ( Herman et al, 2016 ).…”

Complete Elimination of Peripheral Auditory Input Before Onset of Hearing Causes Long-Lasting Impaired Social Memory in Mice

“…In this study, we completely eliminated hearing input from the cochlea to the brain and demonstrated that hearing input is truly necessary for the development of social memory. We hypothesize that hearing deprivation may reorganize functional connectivity between the auditory pathway and social memory circuit, resulting in negative effects on associated brain regions, such as the hippocampus (dCA2, vCA1), mPFC, NAc, and amygdala (Kwon et al, 2021). Also, HL can partially induce chronic inactivation of social memory-related networks, which in turn leads to discrimination failure between familiar and novel conspecifics in deaf mice.…”

Social factors and the neurobiology of pathogen avoidance

“…However, females also avoided the urinary odours of nematode-infected males whose darcin levels were unchanged, supporting the involvement of other constituents of male odours [ 1 ]. In addition, males avoid the odours of, and mating with, LPS-treated females [ 44 ]. The responses to darcin may be dependent on a female's internal state, which is affected by other odour components and sensory/social cues associated with infection threat.…”