Perception of male and female infant cry aversiveness by adult men.

Objective: The study aimed to determine why male infants are abused more frequently than female infants.Background: Infant crying is a well-known trigger for Shaken Baby Syndrome or Abusive Head Trauma (SBS/AHT). For unknown reasons, male infants are more often victims of SBS/AHT than female infants. We hypothesised that this sex difference in victimisation was attributable to either acoustic or movement differences between male and female infants when crying, or to gender stereotypes about infant crying (e.g. 'boys don't cry').Methods: Adult male participants rated auditory and video cry stimuli from male and female infants for aversiveness. Each infant was rated while wearing both blue and pink clothing to denote male or female gender.Results: In two experiments, male infants spent more time producing expiratory phonations than did female infants, and this variable was positively correlated with aversiveness ratings. Including visual stimuli increased male but not female infant cry aversiveness compared with audio stimuli alone. Finally, dressing infants in blue did not increase cry aversiveness.Conclusions: These findings suggest that both the tendency of male infants to produce more expiratory phonations when crying, as well as their visual appearance when crying, may contribute to their increased vulnerability to abuse.

The role of oxytocin signaling in depression and suicidality in returning war veterans.

Many war veterans struggle with depression and suicidality, and separation from the military is a time of particularly high risk. Based on research in non-human animals, we hypothesized that reduced oxytocin signaling would mediate symptoms of depression and suicidality in war veterans recently separated from their close comrades. We also hypothesized that veterans with more frequent contact with comrades would have fewer symptoms of depression and suicidality. In this cross-sectional study, male veterans from the Iraq and Afghanistan wars (n = 86) provided blood and urine samples for measurement of peripheral oxytocin (OT) levels, as well as saliva samples for DNA extraction followed by genotyping of oxytocin receptor gene (OXTR) Single Nucleotide Polymorphisms, and CpG-methylation assessment. Participants also completed a series of mental health questionnaires and interviews. Veterans reported feeling very close to their comrades during war, and missing them greatly upon returning home. Neither peripheral OT levels nor OXTR genotypes were related to symptoms of depression or suicidality. On the other hand, methylation at OXTR CpG -924 was negatively correlated with depressive symptomology, after controlling for possible confounds. Veterans who socialized with comrades more frequently had higher levels of urinary, but not plasma OT, as well as less depressive symptomology. Social connectedness was a strong negative predictor of symptoms of both depression and suicidality, eclipsing the predictive power of other variables such as post-deployment social support, the degree to which participants reported missing their comrades, and the frequency with which they socialized with comrades. Our results suggest that veteran mental health is more impacted by lack of social connectedness than by separation from close comrades per se. While there is some evidence that OXTR methylation relates to depressive symptomology, decreased OT signaling does not appear to mediate the relationship between social disconnectedness and depression or suicidality. Sleep quality and anxiety disorders were also significantly associated with mental health symptoms, independent of social connectedness. Our findings suggest that efforts aimed at alleviating the burden of depression and suicidality in returning war veterans should focus on re-integrating veterans into society and establishing a feeling of social connectedness, as well as on treating anxiety disorders and sleep problems.

The neural correlates of paternal consoling behavior and frustration in response to infant crying.

Human fathers often form strong attachments to their infants that contribute to positive developmental outcomes. However, fathers are also the most common perpetrators of infant abuse, and infant crying is a known trigger. Research on parental brain responses to infant crying have typically employed passive listening paradigms. However, parents usually engage with crying infants. Therefore, we examined the neural responses of 20 new fathers to infant cries both while passively listening, and while actively attempting to console the infant by selecting soothing strategies in a video game format. Compared with passive listening, active responding robustly activated brain regions involved in movement, empathy and approach motivation, and deactivated regions involved in stress and anxiety. Fathers reporting more frustration had less activation in basal forebrain areas and in brain areas involved with emotion regulation (e.g., prefrontal cortex and the supplementary motor area). Successful consolation of infant crying activated regions involved in both action-outcome learning and parental caregiving (anterior and posterior cingulate cortex). Overall, results suggest that active responding to infant cries amplifies activation in many brain areas typically activated during passive listening. Additionally, paternal frustration during active responding may involve a combination of low approach motivation and low engagement of emotion regulation.