| Description |
In 2019, the surgeon general warned that social isolation was the deadliest epidemic facing society (Murthy, 2020). This has only been exacerbated as the effects of social isolation have been recently felt deeply across the globe as the world seemingly shut down in response to the novel Covid-19 pandemic. Furthermore, the effects of social isolation have been seen before as prison inmates placed in solitary confinement are more likely to experience suicidal ideology, irritability, and aggression (Scharf Smith, 2006). Rodents that have been single housed to induce social isolation show similar behaviors to humans in solitary confinement, with aggression as the most commonly reported (Zelikowsky et. al., 2018). Previous work has established that medial prefrontal cortex (mPFC) pyramidal neurons project to multiple subcortical aggression centers (Biro et. al., 2018), and that inhibition of such neurons in mPFC reduces aggression (Takahashi et. al. 2014; Van Heukelum et. al, 2021). Despite this, no work has focused on how this population of neurons may regulate social isolation-induced aggression nor have these neurons been studied in females. Here, we expand on previous work showing a link between decreased mPFC pyramidal neuron activity and aggression in males by examining whether activation of mPFC pyramidal neurons reduces aggression in socially isolated female mice. To this end, we infused a virus encoding the excitatory DREADD, hM3D, fused to mCherry, under the control of the CaMKII promoter, or a control virus expressing mCherry into the mPFC of isolated female C57Bl6/N mice. After isolation, a within subject's design was used to examine the impact of DREADD-mediated activation on aggression. Activation of mPFC pyramidal neurons significantly decreased aggression in isolated mice (Repeated Measures ANOVA, p<.05). While DREADD-mediated activation of mPFC pyramidal neurons decreased attack, it had no effect on other aggressive behaviors, including mounting (p .2079) or aggressive grooming (p .8550). These results support the hypothesis that the mPFC plays an inhibitory role in aggressive behavior. |
