Natural Variation in the Oxytocin Receptor Gene and Rearing Interact to Influence Reproductive and Nonreproductive Social Behavior and Receptor binding

Individual variation in social behavior offers an opportunity to explore gene-by-environment interactions that could contribute to adaptative or atypical behavioral profiles (e.g., autism spectrum disorders). Outbred, socially monogamous prairie voles provide an excellent model to experimentally explore how natural variations in rearing and genetic diversity interact to shape reproductive and nonreproductive social behavior. In this study, we manipulated rearing (biparental versus dam-only), genotyped the intronic NT213739 single nucleotide polymorphism (SNP) of the oxytocin receptor gene (Oxtr), and then assessed how each factor and their interaction related to reciprocal interactions and partner preference in male and female adult prairie voles. We found that C/T subjects reared biparentally formed more robust partner preferences than T/T subjects. In general, dam-only reared animals huddled less with a conspecific in reproductive and nonreproductive contexts, but the effect of rearing was more pronounced in T/T animals. In line with previous literature, C/T animals exhibited higher densities of oxytocin receptor (OXTR) in the striatum (caudoputamen, nucleus accumbens) compared to T/T subjects. There was also a gene-by-rearing interaction in the striatum and insula of females: In the insula, T/T females expressed varying OXTR densities depending on rearing. Overall, this study demonstrates that significant differences in adult reproductive and nonreproductive social behavior and OXTR density can arise due to natural differences in Oxtr, experimental manipulations of rearing, and their interaction

Affective Language, Interpretation Bias and Its Molecular Genetic Variations: Exploring the Relationship Between Genetic Variations of the OXTR Gene (rs53576 and rs2268498) and the Emotional Evaluation of Words Related to the Self or the Other

Several studies have demonstrated links between oxytocin and socio-emotional information processing. Regarding the frequently studied single nucleotide polymorphism (SNP) rs53576 and the less studied, functional polymorphism rs2268498 of the oxytocin receptor (OXTR) gene, previous research suggested that their variants might be associated with different proficiency in the processing of social information. Differences between the genotype variants are not restricted to non-verbal stimulus processing but have also been reported in the verbal domain. Moreover, there is evidence that oxytocin expression influences empathic communication and language development during childhood, indicating that language-based theory-of-mind abilities may be affected by interindividual differences in OXTR genotypes as well. The present study therefore investigates whether two prominent SNPs of the OXTR gene (rs53576 GG vs. A+; rs2268498 TT vs. C+) also play a role in the affective evaluation of verbal stimuli varying in emotional valence and in self-other reference. Participants (N = 149 Caucasian participants, 104 females; A+: n = 80, GG: n = 69; C+: n = 98, TT: n = 51) were presented a series of written, self-, other-, and unreferenced words of positive, negative, and neutral valence and asked to affectively evaluate each word pair as positive, negative, or neutral by button press. In line with previous research, reaction times and accuracy (number of valence-congruent responses) showed a self-positivity bias (i.e., preferential processing of self-related positive words), which, however, was unaffected by participants’ genotype. Regarding affective evaluation of neutral words (interpretation bias), A+ carriers displayed a weaker positive interpretation bias compared to GG carriers in the other– and unreferenced stimulus categories. C+ carriers showed a weaker positive interpretation bias than TT carriers in the self-reference condition and in the other-reference condition. These effects were independent from participants’ gender. The present results suggest that the OXTR genotype and hence participants’ genetic oxytocin sensitivity may cause an interpretation bias in the spontaneous appraisal of neutral words