Is it all in the family? The effects of early social structure on neural–behavioral systems of prairie voles (Microtus ochrogaster)

Abstract

The transition to parenthood is generally associated with a reduction in anxiety or anxiety-like behavior across a wide range of species. In some species, juveniles provide supplementary parental care for younger siblings, a behavior known as alloparenting. Although the fitness consequences of alloparenting behavior have been a focus of evolutionary research, less is known about how alloparenting behavior impacts affective states. In the socially monogamous prairie vole (Microtus ochrogaster), most juveniles exhibit alloparenting behavior, making the species an ideal model for examining the effects of alloparenting on future behavioral outcomes. We randomly assigned juvenile voles to alloparenting (AL) or no alloparenting (NoAL) groups and behaviorally phenotyped them for anxiety-like and social behaviors using the elevated plus maze (EPM), open field test (OFT), startle box, social interaction test, juvenile affiliation test, and partner preference test. AL voles displayed more anxiety-like and less exploratory behavior than NoAL voles, spending significantly less time in the open arms of the EPM and center of an open field. We dissected the CA1 region of the hippocampus and the bed nucleus of the stria terminalis (BNST) from brains of behaviorally phenotyped voles and nontested siblings as well. Decreased BDNF expression in CA1 has generally been associated with increased anxiety-like behavior in other rodents, while an anxiogenic role for BDNF in BNST is less established. Western blot analyses showed that alloparenting experience increased expression of brain derived neurotrophic factor (BDNF) in the bed nucleus of stria terminalis (BNST) but decreased BDNF expression in the CA1 region of hippocampus (CA1) of nontested voles. There were similar differences in BNST BDNF of behaviorally phenotyped voles, and BDNF levels within this region were negatively correlated with exploratory behavior (i.e. time in center of OFT). Our results suggest that BDNF signaling in BNST and CA1 fluctuate with alloparenting experience, and they contribute to an increasingly complex “BDNF hypothesis” in which behavioral effects of this molecule are region-specific.

Paternal deprivation affects social behaviors and neurochemical systems in the offspring of socially monogamous prairie voles

“…All proteins were visualized on the ChemiDoc MP System (Bio-Rad). The specificities of the primary antibodies were validated in previous studies in voles as well as in rats and mice for the CRH system and H3k9ace, which share high homology with prairie voles (Huang et al, 2009; Greenberg et al, 2012; Gupta-Agarwal et al, 2012; Wang et al, 2013; Wu et al, 2014; Galinato et al, 2015; Duclot et al, 2016; Yadawa and Chaturvedi, 2016) . It should be mentioned that the OTR antibody was shown to be able to detect OTR protein in the vole brain tissue via antibody neutralization with an OTR blocking peptide but the signal reduction by overnight incubation with the blocking peptide was not complete (Duclot et al, 2016).…”

Chronic Intranasal Oxytocin Causes Long-Term Impairments in Partner Preference Formation in Male Prairie Voles

“…A 15–20 day old juvenile vole placed in a two-chamber arena provides a friendly, non-threatening stimulus (53,54) to evaluate social motivation. Behavior towards the juvenile was digitally recorded for 10 minutes.…”

Fighting in the home cage: Agonistic encounters and effects on neurobiological markers within the social decision-making network of house mice (Mus musculus)

“…Brains were removed and dissections were made from 2 mm-thick coronal sections taken from a brain matrix. The nucleus accumbens (NAc) and bed nucleus of the stria terminalis (BNST) were dissected using 1mm-diameter bilateral punches and then frozen on dry ice [12]. …”