Author response: Urocortin-3 neurons in the mouse perifornical area promote infant-directed neglect and aggression

Anita E Autry,Brenda Marin-Rodriguez,Dhananjay Bambah-Mukku,Zheng Wu,Vikrant Kapoor,Ilaria Carta,Johannes Kohl,Nimrod D Rubinstein,Victoria Sedwick,Ming Tang,Catherine Dulac

doi:10.7554/elife.64680.sa2

Anita E Autry, Brenda Marin-Rodriguez + Show 9 more

Open Access

https://doi.org/10.7554/elife.64680.sa2

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Abstract

While recent studies have uncovered dedicated neural pathways mediating the positive control of parenting, the regulation of infant-directed aggression and how it relates to adult-adult aggression is poorly understood. Here we show that urocortin-3 (Ucn3)-expressing neurons in the hypothalamic perifornical area (PeFAUcn3) are activated during infant-directed attacks in males and females, but not other behaviors. Functional manipulations of PeFAUcn3 neurons demonstrate the role of this population in the negative control of parenting in both sexes. PeFAUcn3 neurons receive input from areas associated with vomeronasal sensing, stress, and parenting, and send projections to hypothalamic and limbic areas. Optogenetic activation of PeFAUcn3 axon terminals in these regions triggers various aspects of infant-directed agonistic responses, such as neglect, repulsion, and aggression. Thus, PeFAUcn3 neurons emerge as a dedicated circuit component controlling infant-directed neglect and aggression, providing a new framework to understand the positive and negative regulation of parenting in health and disease.

Highlights

Using induction of the immediate early gene (IEG) Fos as a molecular readout of neuronal activation after interaction with pups, we found that urocortin-3 (Ucn3)-expressing neurons in the perifornical area (PeFAUcn3) of the hypothalamus are activated during infant-directed attacks in male and female mice, but not during other forms of aggression
Together with our anatomical data, these results suggest that all major projections are active during pup-directed attacks with preferential involvement of rostro-medial PeFAUcn3 projections to AHi. 287 PeFAUcn3 neuronal projections govern discrete aspects of infant-directed neglect and aggression To test the respective functions of PeFAUcn3 targets, we performed optogenetic activation of PeFAUcn3 terminals in virgin females injected in the PeFA with a conditional virus expressing ChR2 and with optical fibers implanted bilaterally above each projection target (Figure 9)
In control experiments we found that stimulation of PeFAUcn3 projections to ventromedial hypothalamus (VMH), LS and AHi did not impact locomotion, appetitive feeding, or conspecific aggression (Figure 9-figure supplement 1A-J). Altogether, these data suggest that various aspects and degrees of infant-directed neglect and aggression are mediated across PeFAUcn3 projections, with PeFAUcn3 to VMH projections suppressing pup investigation, PeFAUcn3 to LS projections mediating reduced pup handling and low-level aggression, and PeFAUcn3 to AHi projections inducing stereotyped displays of pup334 directed aggression (Figure 10)

Summary

RESULTS

Urocortin-3 expressing cells in the perifornical area are activated during infant-directed aggression To identify neuronal populations involved in infant-directed aggression, we monitored the induction of the immediate early gene (IEG) Fos across brain regions involved in social behavior control, i.e., the hypothalamus and septal and amygdaloid nuclei, in infanticidal virgin males, fathers and mothers after interactions with pups (Figure 1A, B). No sex or state-dependent difference was observed in the number of PeFAUcn neurons in virgin or mated males and females (Figure 1-figure supplement 1C), and most PeFAUcn neurons expressed the vesicular glutamate transporter 2 (Vglut, or Slc17a6; 91.3%±1.2%) suggesting an excitatory function (Figure 1-figure supplement 1D) We conclude from these data that pup-directed aggression, but no other forms of adult aggression or other behaviors, activates excitatory Ucn3+ neurons of the rostral PeFA. To further determine the respective organization of these projections from the PeFA and their involvement in pup254 directed aggression, we performed CTB-mediated retrograde tracing from LS, VMH and AHi individually and quantified the overlap between CTB labelling and Fos expression in the PeFA of virgin males after infant-directed attack (Figure 7 D, E). These functional connectivity data demonstrates that PeFAUcn projections to AHi make significantly stronger connections (Figure 8D) with higher probability of release (Figure 8E bottom) compared to PeFAUcn projections to other brain areas

Discussion

492 Acknowledgements

508 METHODS