No abstract

SummaryData analysis workflows in many scientific domains have become increasingly complex and flexible. To assess the impact of this flexibility on functional magnetic resonance imaging (fMRI) results, the same dataset was independently analyzed by 70 teams, testing nine ex-ante hypotheses. The flexibility of analytic approaches is exemplified by the fact that no two teams chose identical workflows to analyze the data. This flexibility resulted in sizeable variation in hypothesis test results, even for teams whose statistical maps were highly correlated at intermediate stages of their analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Importantly, meta-analytic approaches that aggregated information across teams yielded significant consensus in activated regions across teams. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset. Our findings show that analytic flexibility can have substantial effects on scientific conclusions, and demonstrate factors related to variability in fMRI. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for multiple analyses of the same data. Potential approaches to mitigate issues related to analytical variability are discussed.

In the postpartum period, the maternal brain experiences both structural and functional plasticity. Although we have a growing understanding of the responses of the human maternal brain to infant stimuli, little is known about the intrinsic connectivity among those regions during the postpartum months. Resting‐state functional connectivity (rsFC) provides a measure of the functional architecture of the brain based upon intrinsic functional connectivity (ie, the temporal correlation in blood oxygenation level dependent signal when the brain is not engaged in a specific task). In the present study, we used resting‐state functional magnetic resonance imaging to examine how later postpartum months are associated with rsFC and maternal behaviours. We recruited a sample of 47 socioeconomically diverse first‐time mothers with singleton pregnancies. Because the amygdala has been shown to play a critical role in maternal behaviours in the postpartum period, this was chosen as the seed for a seed‐based correlation analysis. For the left amygdala, later postpartum months were associated with greater connectivity with the anterior cingulate gyrus, left nucleus accumbens, right caudate and left cerebellum (P < 0.05, false discovery rate corrected). Furthermore, in an exploratory analysis, we observed indications that rsFC between the left amygdala and left nucleus accumbens was positively associated with maternal structuring during a mother child‐interaction. In addition, later postpartum months were associated with greater connectivity between the right amygdala and the bilateral caudate and right putamen. Overall, we provide evidence of relationships between postpartum months and rsFC in the regions involved in salience detection and regions involved in maternal motivation. Greater connectivity between the amygdala and nucleus accumbens may play a role in positive maternal behaviours.

During the early postpartum period, mothers exhibit increased amygdala responses to positive infant expressions, which are important for positive mother-infant relationships. Socioeconomic disadvantage is associated with altered amygdala response to emotional stimuli as well as more negative mother-infant relationships. However, little is known about the role of socioeconomic disadvantage in neural responses specifically to infants. Thus, we examined whether socioeconomic disadvantage (indexed by lower income-to-needs ratio) is associated with neural responses to infant emotions and parenting behaviors among new mothers. Using fMRI, neural responses to infants’ emotional expressions (positive, negative, and neutral faces) were assessed among 39 low- and middle-income first-time mothers during 0–6 postpartum months. Lower income-to-needs ratio was associated with dampened amygdala responses to positive infant faces, but increased amygdala responses to negative infant faces. An indirect effect of socioeconomic disadvantage on emotional availability via amygdala activation suggests that socioeconomic disadvantage is associated with heightened neural sensitivity to infants’ negative emotions, which is further associated with mothers’ intrusiveness observed during interactions with their own infant. The findings suggest that low-income mothers may be more vulnerable to altered neural processing of infants’ emotional expressions which may further influence mothers’ emotional availability during interactions with their own infants.

Face processing in mothers is linked to mother–infant social communication, which is critical for parenting and in turn for child development. Neuroimaging studies of child maltreatment-exposed (CME) mothers are sparse compared to studies of mothers with postpartum depression, which have suggested blunted amygdala reactivity to infant stimuli. We expected to see a similar pattern in CME mothers. Based on broader studies in trauma-exposed populations, we anticipated increased amygdala reactivity to negative adult face stimuli in a comparison task in CME mothers given heightened evaluation of potential threat. We examined Neuroimaging studies of mothers with childhood maltreatment exposure (CME) (18–37 years old), who performed infant (N = 45) and/or adult (N = 46) face processing tasks. CME mothers exhibited blunted bilateral amygdala reactivity to infant faces. There was no between-group difference in amygdala reactivity to adult faces. In infant and adult face processing tasks regardless of CME, superior temporal gyrus activation was increased for negative-valence stimuli. Our preliminary findings suggest that childhood maltreatment alters maternal processing of infant social cues, a critical skill impacting infant socioemotional development.