Distinct preoptic‐ BST nuclei dissociate paternal and infanticidal behavior in mice

Abstract

Paternal behavior is not innate but arises through social experience. After mating and becoming fathers, male mice change their behavior toward pups from infanticide to paternal care. However, the precise brain areas and circuit mechanisms connecting these social behaviors are largely unknown. Here we demonstrated that the c-Fos expression pattern in the four nuclei of the preoptic-bed nuclei of stria terminalis (BST) region could robustly discriminate five kinds of previous social behavior of male mice (parenting, infanticide, mating, inter-male aggression, solitary control). Specifically, neuronal activation in the central part of the medial preoptic area (cMPOA) and rhomboid nucleus of the BST (BSTrh) retroactively detected paternal and infanticidal motivation with more than 95% accuracy. Moreover, cMPOA lesions switched behavior in fathers from paternal to infanticidal, while BSTrh lesions inhibited infanticide in virgin males. The projections from cMPOA to BSTrh were largely GABAergic. Optogenetic or pharmacogenetic activation of cMPOA attenuated infanticide in virgin males. Taken together, this study identifies the preoptic-BST nuclei underlying social motivations in male mice and reveals unexpected complexity in the circuit connecting these nuclei.

Moxd1 Is a Marker for Sexual Dimorphism in the Medial Preoptic Area, Bed Nucleus of the Stria Terminalis and Medial Amygdala

“…Brain sections were processed for ISH as previously described (Tsuneoka et al, 2013, 2015) with some modifications. Briefly, the sections were washed with PBS containing 0.1% Tween-20 (PBT), postfixed with 4% PFA in PBS for 10 min at room temperature.…”

“…For the other areas, every third coronal section from the whole brain except the olfactory bulb from different male mice ( n = 4) were randomly selected and stained for Moxd1 ISH combined with IHC for calbindin. Identification of the brain areas was done according to the chemoarchitectonic atlases (Dong, 2008; Paxinos and Watson, 2010; Martínez-García et al, 2012) and our previous study (Tsuneoka et al, 2013, 2015). …”

Effects of repeated pup exposure on behavioral, neural, and adrenocortical responses to pups in male California mice (Peromyscus californicus)

“…We refer to differences with p<0.0167 as significant and those with 0.0167<p<0.05 as nominally significant. Within-group comparisons on behavioral data were analyzed with Friedman tests and Nemenyi post-hoc tests (Pohlert, 2015). Nemenyi’s post-hoc test accounts for family-wise error, and no p–adjustment is required (Nemenyi, 1963; Pohlert, 2015).…”

Parenting in animals

“…In the past few years there has also been an emerging focus on the switch from infanticide to fathering behavior in laboratory mice [1,34]; Table 1. It has been known for a long time that some rodents that do not display male parenting in nature may do so in the laboratory [35], either as the result of extended exposure to young or as the result of becoming a father.…”

“…These males are usually infanticidal until their parenting behavior is “turned on”. One laboratory has focused on the neuroanatomy of this switch, implicating neurons in the rhomboid nucleus of the bed nucleus of the stria terminalis (rhBNST) in infanticidal behavior in male mice, and neurons in the central medial preoptic area (cMPOA) as involved in fathering [34]. This study, however, did not focus on the neurochemical identity of the cells.…”