Annual Research Review: All mothers are not created equal: neural and psychobiological perspectives on mothering and the importance of individual differences

Abstract

Quality of mothering relies on the integrity of multiple physiological and behavioral systems and on two maternal factors, one proximal and one distal, that have a great impact on how a mother mothers: postpartum depression and early experiences. To mother appropriately requires the action of systems that regulate sensation, perception, affect, reward, executive function, motor output and learning. When a mother is at risk to engage in less than optimal mothering, such as when she is depressed or has experienced adversity in childhood, the function of many or all of maternal and related systems may be affected. In this paper, we will review what is currently known about the biological basis of mothering, with attention to literature on hormones but with a particular focus on recent advances in the fields of functional neuroimaging. Instead of discussing strictly 'maternal' brain imaging studies, we instead use a systems approach to survey important findings relevant to brain systems integral to and/or strongly related to the mothering experience: (a) social behavior; (b) reward and affect; (c) executive function; and (d) maternal behavior. We find that there are many commonalities in terms of the brain regions identified across these systems and, as we would expect, all are sensitive to the influence of, or function differently in the context of, depression and adverse early experience. It is likely that the similarity and cross-talk between maternal, affect and stress systems, observed behaviorally, hormonally and in the context of brain function, allows for mood disturbance and early adverse experiences to have a significant impact on the quality of mothering and the motivation to mother.

Father's brain is sensitive to childcare experiences

“…Consistent with findings in other mammals (10), studies on brain-behavior associations in human mothers describe links between mother-infant synchrony and brain activation in the mother's subcortical regions, including the amygdala, nucleus accumebens, and hippocampus (11,13). In contrast, the one study testing human fathers' brainbehavior associations showed correlations with cortical activation (17).…”

“…Animal studies have demonstrated that mammalian mothering is supported by evolutionarily ancient structures implicated in emotional processing, vigilance, motivation, and reward, which are rich in oxytocin receptors, including the amygdala, hypothalamus, nucleus accumbens, and ventral tegmental area (VTA), and that these regions are sensitive to caregiving behavior (9,10). Imaging studies of human mothers found activation in similar areas, combined with paralimbic insula-cingulate structures that imbue infants with affective salience, ground experience in the present moment and enable maternal simulation of infant states (11)(12)(13). These structures implicate a phylogenetically ancient network of emotional processing that rapidly detects motivationally salient and survival-related cues (14) and enables parents to automatically identify and immediately respond to infant distress, thereby maximizing survival.…”

“…In humans, this emotional processing network is complemented by a cortical mentalizing network of frontopolar-medial-prefrontal-temporo-parietal structures involved in social understanding, theory of mind, and cognitive empathy, including the medial prefrontal cortex (mPFC), frontopolar cortex, superior temporal sulcus (STS), and temporal poles (15). The mentalizing network plays an important role in individuals' ability to infer mental states from behavior, is already activated during the parents' first weeks of parenting, and enables parents to cognitively represent infant states, predict infant needs, and plan future caregiving (11)(12)(13).…”

Variations in Maternal Behavior—Oxytocin and Reward Pathways—Peripheral Measures Matter?!

“…While animal models of maternal behavior are compelling and have identified key regions in a putative mothering circuit, it is also clear that human behaviors are far more complex. Processes such as cognitive flexibility, attentional control, working memory, and the mother's ability to understand the intentions and emotions of her child are fundamental components of human mothering (Barrett and Fleming, 2011).In this issue of Neuropsychopharmacology, Atzil et al (2011) performed functional magnetic resonance imaging (fMRI) to assess the neural circuitry of new mothers when their infants were 4-6 months old. The fMRIs were recorded while mothers viewed a 2-min movie of their own infant during solitary play and a 2-min movie of themselves during the mother-infant interaction vs a 2-min movie of an unfamiliar infant and segments of mother-infant interactions.…”

“…While animal models of maternal behavior are compelling and have identified key regions in a putative mothering circuit, it is also clear that human behaviors are far more complex. Processes such as cognitive flexibility, attentional control, working memory, and the mother's ability to understand the intentions and emotions of her child are fundamental components of human mothering (Barrett and Fleming, 2011).…”