Parental responses to their children are crucially influenced by stress. However, brain-based mechanistic understanding of the adverse effects of parenting stress and benefits of therapeutic interventions is lacking. We studied maternal brain responses to salient child signals as a function of Mom Power (MP), an attachment-based parenting intervention established to decrease maternal distress. Twenty-nine mothers underwent two functional magnetic resonance imaging brain scans during a baby-cry task designed to solicit maternal responses to child's or self's distress signals. Between scans, mothers were pseudorandomly assigned to either MP (n = 14) or control (n = 15) with groups balanced for depression. Compared to control, MP decreased parenting stress and increased child-focused responses in social brain areas highlighted by the precuneus and its functional connectivity with subgenual anterior cingulate cortex, which are key components of reflective self-awareness and decision-making neurocircuitry. Furthermore, over 13 weeks, reduction in parenting stress was related to increasing child- versus self-focused baby-cry responses in amygdala–temporal pole functional connectivity, which may mediate maternal ability to take her child's perspective. Although replication in larger samples is needed, the results of this first parental-brain intervention study demonstrate robust stress-related brain circuits for maternal care that can be modulated by psychotherapy.

There is a growing understanding of the neural mechanisms of human maternal attachment. Human mothers’ neural responses to infants are associated with their behavioral sensitivity observed during interactions with infants. The current symposium aims to provide understanding of the core neural basis for mother-infant attachment, how prenatal and postnatal risk factors influence the maternal brain, and finally whether the negative changes in the maternal brain may be reversed by an intervention effort. The first paper presents converging evidence on neural, psychological and physiological responses to infants in new mothers across diverse cultural contexts. The paper highlights the common core neural processes of mother-infant attachment, which sets the foundation of understanding maternal brain’s successful and unsuccessful adaptation to parenthood. The second paper presents the role of prenatal risk factors, specifically prenatal maternal anxiety, in maternal brain adaptation to parenthood. This longitudinal study suggests that negative effects of maternal anxiety in mothers’ neural adaptation to parenthood may emerge during pregnancy. The third paper presents evidence that socioeconomic stress may also disrupt mothers’ neural adaptation to parenthood. Low family income is associated with dampened neural sensitivity to positive infant expressions and elevated neural sensitivity to negative infant expressions, which further influence disruptions in maternal behavioral responsiveness to own infants. The last presentation suggests that aberrant neural sensitivity to infants among distressed mothers may be improved via an intervention. Among depressed mothers, interventions to improve mental health reduced parental stress and strengthened neural functional connectivity in response to their infant.

Optimal responsiveness to infant cues, an integral component of parental caregiving, is thought to be determined by multiple factors including maternal mood, previous experiences of caregiving, and infant characteristics. This thesis builds on previous work and details novel investigations of brain, affective, and attitudinal responses to infants/children. In the first two studies, we investigated the effects of maternal mood and parity (previous experiences of caregiving) on brain response to affectively positive infant pictures using functional magnetic resonance imaging (fMRI). We found that mothers with postpartum depression showed an elevated right amygdala response to infant pictures in comparison to mothers without PPD and depressed non- mothers. Further, functional connectivity between the bilateral amygdalae and the right insular cortex was negatively correlated with clinical symptoms (self-reported depression and anxiety). Therefore, as depression and anxiety symptoms increased amygdala to insular cortex connectivity decreases and vice versa. In the third study, we developed a novel data-driven infant cuteness (DDIcute) metric using the infant pictures presented in the first two studies. In line with ethological postulations on cuteness (infant characteristics), we found that infant pictures with a higher DDIcute score were associated with increased positive/approach-related affective responses and decreased negative/avoidant-related affective responses. In the fourth study, we investigated whether the sex differences in attitudes about children and childcare were moderated by pet ownership/care (previous experiences of caregiving). We found that pet ownership and care eliminated sex differences in attitudes about children and childcare. This effect was driven by males; compared to males with low levels of experience caring for pets, males with high levels of experience caring for pets had more positive attitudes about children and childcare. / Thesis / Doctor of Science (PhD) / The work presented in this thesis adds to literature on human caregiving. In different studies we investigated brain, emotional, and attitudinal responses to human babies and children in people with and without depression as well as in people with different levels of caregiving experience. In the first two studies, we measured brain response to smiling baby pictures in depressed and non-depressed mothers and non-mothers. The amygdala is a brain region that is involved in the neurobiology underlying both depression and maternal behaviour. We found that amygdala response was the highest among mothers with postpartum depression. We also found that the coupled activity of the left and right amygdalae and another brain region called the insula was altered in mothers with postpartum depression. In the third study, we measured facial features of the baby faces presented in the first two studies to develop a measure of cuteness. We also measured emotional responses to the baby faces. We found that cuter infants elicited more positive and less negative emotional responses. In the fourth study, we measured differences in attitudes about children and caregiving between men and women who did and did not own and care for pets—specifically dogs and/or cats. We found that compared to men who did not own and/or care for pets, men who had more experience caring for pets had more positive attitudes about children and childcare.