Maternal brain resting-state connectivity in the postpartum period

A common neural response to perceiving but not implicitly regulating infant and adult affect in postpartum mothers

The transition to parenthood requires parents develop caregiving behaviors, such as the ability to identify their infant's emotions and regulate their own emotional response. Research has identified patterns of neural activation in parenting contexts that are interpreted as socioemotional processing. However, no prior research has directly tested whether mothers' neural responses to their infant's affect are the same as those involved in emotion perception/experience and regulation in other contexts. We employed conjunction analyses to clarify which components of mothers' neural response to viewing their infant's affect are shared with passively viewing and labeling adult affective faces (emotion perception/experience and implicit emotion regulation, respectively) in 24 mothers three months postpartum. Our results support a common neural response to viewing infant and adult affect in regions associated with emotion perception/experience (bilateral hippocampi, amygdalae, thalami, orbitofrontal cortex, and ventrolateral prefrontal cortex), but no areas of common response to viewing negative infant affect and implicitly regulating negative adult affect outside of the occipital lobe and cerebellum. This study provides corroborating evidence for shared neural patterns being involved in perceiving/experiencing infant and adult affect but not implicit regulation of infant and adult negative affect.

Maternal cortisol concentration is associated with reduced brain activation to infant cry and more intrusive parenting behavior

Previous research indicates that maternal cortisol function and maternal brain response to infant are each in turn related to variations in parenting behavior. However, little is known about how maternal cortisol and maternal brain function are associated, thus studying these two mechanisms together may improve our understanding of how maternal cortisol assessed during interactions with own infant is associated with brain response to infant cry. First-time mothers (N = 59) of infants aged 3-4 months old were recruited to participate. Mothers' cortisol concentration was measured during a naturalistic interaction with their infant and their behavior was coded for two parenting behaviors-- maternal sensitivity and non-intrusiveness. In an fMRI session, mothers listened to their own infant and a control infant crying. Higher cortisol concentration was associated with more intrusive behavior. We found greater cortisol concentration was further associated with decreased activation in the brain to infant cry in the right precentral gyrus, the left culmen extending into the left inferior temporal gyrus and fusiform, two clusters in the superior temporal gyrus, and in the medial frontal gyrus. We also found that lower activation in these regions was associated with more intrusive maternal behavior. These data demonstrate the associations between maternal cortisol concentration and reduced brain activation to infant cry in both motor planning and auditory processing regions in predicting intrusive parenting behavior.

Is melanin-concentrating hormone in the medial preoptic area a signal for the decline of maternal care in late postpartum?

This manuscript proposes that melanin-concentrating hormone (MCH) in the medial preoptic area (MPOA) is an neurochemical signal evolved to trigger the declining process of maternal care. MCH in the MPOA appears only after parturition and is progressively increased with the progression of lactation, while maternal behavior declines progressively. Intra-MPOA injection of MCH decreases active maternal responses. MCH is also highly responsive to infant characteristics and maternal condition. Behavioral changes induced by MCH in late postpartum period are conducive to the decline of infant-directed maternal behavior. The MPOA MCH system may mediate the maternal behavior decline by suppressing the maternal approach motivation and/or increasing maternal withdrawal via its inhibitory action onto the mesolimbic dopamine D1/D2 receptors and its stimulating action on serotonin 5-HT2C receptors in the ventral tegmental area. Research into the MCH maternal effects will enhance our understanding of the neurochemical mechanisms underlying the maternal behavior decline.

Protective role of parenthood on age-related brain function in mid- to late-life

The experience of parenthood can profoundly alter one's body, mind, and environment, yet we know little about the long-term associations between parenthood and brain function and aging in adulthood. Here, we investigate the link between number of children parented (parity) and age on brain function in 19,964 females and 17,607 males from the UK Biobank. In both females and males, increased parity was positively associated with functional connectivity, particularly within the somato/motor network. Critically, the spatial topography of parity-linked effects was inversely correlated with the impact of age on functional connectivity across the brain for both females and males, suggesting that a higher number of children is associated with patterns of brain function in the opposite direction to age-related alterations. These results indicate that the changes accompanying parenthood may confer benefits to brain health across the lifespan, highlighting the importance of future work to understand the associated mechanisms.

EEG coherence before and after giving birth

During pregnancy and the postpartum period, changes in brain volume and in motivational, sensory, cognitive, and emotional processes have been described. However, to date, longitudinal modifications of brain function have been understudied. To explore regional cortical coupling, in pregnancy and at 3 months postpartum, we analyzed resting-state electroencephalographic (EEG) coherence in the delta, theta, alpha1, alpha2, beta1, and beta2 frequency bands across frontal and parietal regions of the maternal brain (Fp1, Fp2, F3, F4, P3, and P4). We found that from pregnancy to the postpartum period, mothers showed less intrahemispheric EEG coherence between the frontal and parietal regions in the alpha1 and alpha2 bands, as well as greater interhemispheric EEG coherence between frontopolar regions in the beta2 band. These changes suggest decreased inhibition of neural circuits. These neurophysiological changes may represent an adaptive process characteristic of motherhood.

Brain circuits for maternal sensitivity and pain involving anterior cingulate cortex among mothers receiving buprenorphine treatment for opioid use disorder

Opioid-induced deficits in maternal behaviors are well-characterized in rodent models. Amid the current epidemic of opioid use disorder (OUD), prevalence among pregnant women has risen sharply. Yet, the roles of buprenorphine replacement treatment for OUD (BT/OUD) in the brain functions of postpartum mothers are unclear. Using functional magnetic resonance imaging (fMRI), we have developed an evolutionarily conserved maternal behavior neurocircuit (MBN) model to study human maternal care versus defensive/aggressive behaviors critical to mother-child bonding. The anterior cingulate gyrus (ACC) is not only involved in the MBN for mother-child bonding and attachment, but also part of an opioid sensitive "pain-matrix". The literature suggests that prescription opioids produce physical and emotional "analgesic" effects by disrupting specific resting-state functional connectivity (rs-FC) of ACC to regions related to MBN. Thus, in this longitudinal study, we report findings of overlapping MBN and pain matrix circuits, for mothers with chronic exposure of BT/OUD. A total of 32 mothers were studied with 6 min rs-FC at 1 month (T1) and 4 months postpartum (T2), including seven on BT/OUD and 25 non-BT/OUD mothers as a comparison group. We analyzed rs-FC between the insula, putamen, and the dorsal anterior cingulate cortex (DACC) and rostral ACC (RACC), as the regions of interest that mediate opioid analgesia. BT/OUD mothers, as compared to non-BT/OUD mothers, showed less left insula-RACC rs-FC but greater right putamen-DACC rs-FC at T1, with these between-group differences diminished at T2. Some of these rs-FC results were correlated with the scores of postpartum parental bonding questionnaire. We found time-by-treatment interaction effects on DACC and RACC-dependent rs-FC, potentially identifying brain mechanisms for beneficial effects of BT, normalizing dysfunction of maternal brain and behavior over the first four months postpartum. This study complements recent studies to ascertain how BT/OUD affects maternal behaviors, mother-child bonding, and intersubjectivity and reveals potential MBN/pain-matrix targets for novel interventions.

Structural and functional improvement of amygdala sub-regions in postpartum depression after acupuncture

Objective

This study aimed to analyze the changes in structure and function in amygdala sub-regions in patients with postpartum depression (PPD) before and after acupuncture.

Methods

A total of 52 patients with PPD (All-PPD group) were included in this trial, 22 of which completed 8 weeks of acupuncture treatment (Acu-PPD group). An age-matched control group of 24 healthy postpartum women (HPW) from the hospital and community were also included. Results from the 17-Hamilton Depression Scale (17-HAMD) and the Edinburgh Postnatal Depression Scale (EPDS) were evaluated, and resting-state functional magnetic resonance imaging (rs-fMRI) scans were performed at baseline and after the acupuncture treatment. Sub-regions of the amygdala were used as seed regions to measure gray matter volume (GMV) and analyzed for resting-state functional connectivity (RSFC) values separately. Finally, correlation analyses were performed on all patients with PPD to evaluate association values between the clinical scale scores, GMV, and RSFC values, while controlling for age and education. Pearson's correlation analyses were conducted to investigate the relevance between GMV and RSFC values of brain regions that differed before and after acupuncture treatment and clinical scale scores in Acu-PPD patients.

Results

The HAMD scores for Acu-PPD were reduced after acupuncture treatment (P < 0.05), suggesting the positive effects of acupuncture on depression symptoms. Structurally, the All-PPD group showed significantly decreased GMV in the left lateral part of the amygdala (lAMG.L) and the right lateral part of the amygdala (lAMG.R) compared to the HPW group (P < 0.05). In addition, the GMV of lAMG.R was marginally increased in the Acu-PPD group after acupuncture (P < 0.05). Functionally, the Acu-PPD group showed a significantly enhanced RSFC between the left medial part of the amygdala (mAMG.L) and the left vermis_6, an increased RSFC between the right medial part of the amygdala (mAMG.R) and left vermis_6, and an increased RSFC between the lAMG.R and left cerebelum_crus1 (P < 0.05). Moreover, correlation studies revealed that the GMV in the lAMG.R was significantly related to the EPDS scores in the All-PPD group (P < 0.05).

Conclusion

Our findings demonstrated that the structure of amygdala sub-regions is impaired in patients with PPD. Acupuncture may improve depressive symptoms in patients with PPD, and the mechanism may be attributed to changes in the amygdala sub-region structure and the functional connections of brain areas linked to the processing of negative emotions. The fMRI-based technique can provide comprehensive neuroimaging evidence to visualize the central mechanism of action of acupuncture in PPD.

The maternal brain is more flexible and responsive at rest: effective connectivity of the parental caregiving network in postpartum mothers

The field of neuroscience has largely overlooked the impact of motherhood on brain function outside the context of responses to infant stimuli. Here, we apply spectral dynamic causal modelling (spDCM) to resting-state fMRI data to investigate differences in brain function between a group of 40 first-time mothers at 1-year postpartum and 39 age- and education-matched women who have never been pregnant. Using spDCM, we investigate the directionality (top-down vs. bottom-up) and valence (inhibition vs excitation) of functional connections between six key left hemisphere brain regions implicated in motherhood: the dorsomedial prefrontal cortex, ventromedial prefrontal cortex, posterior cingulate cortex, parahippocampal gyrus, amygdala, and nucleus accumbens. We show a selective modulation of inhibitory pathways related to differences between (1) mothers and non-mothers, (2) the interactions between group and cognitive performance and (3) group and social cognition, and (4) differences related to maternal caregiving behaviour. Across analyses, we show consistent disinhibition between cognitive and affective regions suggesting more efficient, flexible, and responsive behaviour, subserving cognitive performance, social cognition, and maternal caregiving. Together our results support the interpretation of these key regions as constituting a parental caregiving network. The nucleus accumbens and the parahippocampal gyrus emerging as 'hub' regions of this network, highlighting the global importance of the affective limbic network for maternal caregiving, social cognition, and cognitive performance in the postpartum period.

Altered MRI Diffusion Properties of the White Matter Tracts Connecting Frontal and Thalamic Brain Regions in First-Episode, Drug-Naïve Patients With Postpartum Depression

BACKGROUND

Although progress has been made in exploring postpartum depression (PPD), the involvement of cerebral structure connectivity in PPD patients keeps unclear.

PURPOSE

To explore structural connectivity alternations in mothers with PPD, diffusion tensor imaging (DTI) and automated fiber quantification (AFQ) were used to calculate brain white matter microstructure properties.

STUDY TYPE

Cross-sectional.

POPULATION

A total of 51 women with first-episode, treatment-näive PPD, and 49 matched healthy postpartum women (HPW) controls.

FIELD STRENGTH

A 3.0 T; single-shot echo-planar imaging sequence.

ASSESSMENT

DTI measurements of fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were obtained for 18 specific white matter tracts. The relationship between PDD symptoms, hormone levels, and postpartum days was also investigated.

STATISTICAL TESTS

Two sample t test and Pearson's correlation analysis. The analysis was performed by using a permutation-based multiple-comparison correction approach, with the threshold of P < 0.05 (family wise error corrected [FWE-corrected]) separately across the four different outcome measures.

RESULTS

Women with PPD showed significantly increased FA and AD in right anterior thalamic radiation (ATR) tract and significantly increased FA and significantly reduced RD in the cingulum tract, compared to women without PPD. The RD values of right cingulum were significantly positively correlated with postpartum days in HPW (r = 0.39). There were no significant relationships between brain measures and hormone levels in either patients or controls.

DATA CONCLUSIONS

DTI measures have revealed altered integrity in the white matter of the cortical-thalamic circuits in women with PPD compared to HPW. Damage to these circuits may be a structural basis for the impaired emotional regulation and blunted mother-infant bonding in mothers with PPD and a potential target for the development of new treatments.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 3.

Mapping the effects of pregnancy on resting state brain activity, white matter microstructure, neural metabolite concentrations and grey matter architecture

While animal studies have demonstrated a unique reproduction-related neuroplasticity, little is known on the effects of pregnancy on the human brain. Here we investigated whether pregnancy is associated with changes to resting state brain activity, white matter microstructure, neural metabolite concentrations and grey matter architecture using a comprehensive pre-conception cohort study. We show that pregnancy leads to selective and robust changes in neural architecture and neural network organization, which are most pronounced in the Default Mode Network. These neural changes correlated with pregnancy hormones, primarily third-trimester estradiol, while no associations were found with other factors such as osmotic effects, stress and sleep. Furthermore, the changes related to measures of maternal-fetal bonding, nesting behavior and the physiological responsiveness to infant cues, and predicted measures of mother-infant bonding and bonding impairments. These findings suggest there are selective pregnancy-related modifications in brain structure and function that may facilitate peripartum maternal processes of key relevance to the mother-infant dyad.

Empathy for others versus for one's child: Associations with mothers' brain activation during a social cognitive task and with their toddlers' functioning

Caregivers who are higher in dispositional empathy tend to have children with better developmental outcomes; however, few studies have considered the role of child-directed (i.e., "parental") empathy, which may be relevant for the caregiver-child relationship. We hypothesized that mothers' parental empathy during their child's infancy will be a stronger predictor of their child's social-emotional functioning as a toddler than will mothers' dispositional empathy. We further explored whether parental and dispositional empathy have shared or distinct patterns of neural activation during a social-cognitive movie-watching task. In 118 mother-infant dyads, greater parental empathy assessed when infants were 6 months old was associated with more social-emotional competencies and fewer problems in the children 1 year later, even after adjusting for dispositional empathy. In contrast, dispositional empathy was not associated with child functioning when controlling for parental empathy. In a subset of 20 mothers, insula activation was positively associated with specific facets of both dispositional and parental empathy, whereas right temporoparietal junction activation was associated only with parental empathy. Thus, dispositional and parental empathy appear to be dissociable by both brain and behavioral metrics. Parental empathy may be a viable target for interventions, especially for toddlers at risk for developing social-emotional difficulties.

Trait coping styles and the maternal neural and behavioral sensitivity to an infant

During the postpartum period, new mothers experience drastic changes in their body, brain, and life circumstances. Stress from the emotional and physical demands of caring for an infant is associated with negative mood and parenting outcomes. The use of active coping strategies can increase mothers’ resilience during the postpartum period. However, little is known about the association between coping styles and maternal brain responses to infant cues. In the current study, we examined the associations among trait coping style, maternal brain responses, and behavioral sensitivity in a socioeconomically diverse sample of first-time mothers (N = 59). The use of more active trait coping strategies compared to passive coping strategies was associated with increased brain responses to infant cry sounds in brain regions that are critically involved in motivation and emotion regulation—substantia nigra, anterior cingulate gyrus, and inferior frontal gyrus. Increased brain activations in the midbrain and anterior cingulate gyrus were further associated with higher levels of maternal sensitivity observed during interactions with the infant. Thus, the findings provide support for mothers’ use of more active coping styles to promote neural and behavioral resilience for a positive transition to parenthood.

Maternal socioeconomic disadvantage, neural function during volitional emotion regulation, and parenting

The transition to becoming a mother involves numerous emotional challenges, and the ability to effectively keep negative emotions in check is critical for parenting. Evidence suggests that experiencing socioeconomic disadvantage interferes with parenting adaptations and alters neural processes related to emotion regulation. The present study examined whether socioeconomic disadvantage is associated with diminished neural activation while mothers engaged in volitional (i.e., purposeful) emotion regulation. 59 mothers, at an average of 4 months postpartum, underwent fMRI scanning and completed the Emotion Regulation Task (ERT). When asked to regulate emotions using reappraisal (i.e., Reappraise condition; reframing stimuli in order to decrease negative emotion), mothers with lower income-to-needs ratio exhibited dampened neural activation in the dorsolateral and ventrolateral PFC, middle frontal and middle temporal gyrus, and caudate. Without explicit instructions to down-regulate (i.e., Maintain condition), mothers experiencing lower income also exhibited dampened response in regulatory areas, including the middle frontal and middle temporal gyrus and caudate. Blunted middle frontal gyrus activation across both Reappraise and Maintain conditions was associated with reduced maternal sensitivity during a mother-child interaction task. Results of the present study demonstrate the influence of socioeconomic disadvantage on prefrontal engagement during emotion regulation, which may have downstream consequences for maternal behaviors.

An epigenomic shift in amygdala marks the transition to maternal behaviors in alloparenting virgin female mice

Adults of many species will care for young offspring that are not their own, a phenomenon called alloparenting. However, in many cases, nonparental adults must be sensitized by repeated or extended exposures to newborns before they will robustly display parental-like behaviors. To capture neurogenomic events underlying the transition to active parental caring behaviors, we analyzed brain gene expression and chromatin profiles of virgin female mice co-housed with pregnant dams during pregnancy and after birth. After an initial display of antagonistic behaviors and a surge of defense-related gene expression, we observed a dramatic shift in the chromatin landscape specifically in amygdala of the pup-exposed virgin females compared to females co-housed with mother before birth, accompanied by a dampening of anxiety-related gene expression. This epigenetic shift coincided with hypothalamic expression of the oxytocin gene and the emergence of behaviors and gene expression patterns classically associated with maternal care. The results outline a neurogenomic program associated with dramatic behavioral changes and suggest molecular networks relevant to human postpartum mental health.

Less can be more: Fine tuning the maternal brain

PAWLUSKI, J.L., Hoekzema, E., Leuner, B., and Lonstein, J.S. Less can be more: Fine tuning the maternal brain. NEUROSCI BIOBEHAV REV (129) XXX-XXX, 2022. Plasticity in the female brain across the lifespan has recently become a growing field of scientific inquiry. This has led to the understanding that the transition to motherhood is marked by some of the most significant changes in brain plasticity in the adult female brain. Perhaps unexpectedly, plasticity occurring in the maternal brain often involves a decrease in brain volume, neurogenesis and glial cell density that presumably optimizes caregiving and other postpartum behaviors. This review summarizes what we know of the 'fine-tuning' of the female brain that accompanies motherhood and highlights the implications of these changes for maternal neurobehavioral health. The first part of the review summarizes structural and functional brain changes in humans during pregnancy and postpartum period with the remainder of the review focusing on neural and glial plasticity during the peripartum period in animal models. The aim of this review is to provide a clear understanding of when 'less is more' in maternal brain plasticity and where future research can focus to improve our understanding of the unique brain plasticity occurring during matrescence.

Recent Neuroscience Advances in Human Parenting

The transition to parenthood entails brain adaptations to the demands of caring for a newborn. This chapter reviews recent neuroscience findings on human parenting, focusing on neuroimaging studies. First, we describe the brain circuits underlying human maternal behavior, which comprise ancient subcortical circuits and more sophisticated cortical regions. Then, we present the short-term and long-term functional and structural brain adaptations that characterize the transition to motherhood, discuss the long-term effects of parenthood on the brain, and propose several underlying neural mechanisms. We also review neuroimaging findings in biological fathers and alloparents (such as other relatives or adoptive parents), who engage in parenting without directly experiencing pregnancy or childbirth. Finally, we describe perinatal mental illnesses and discuss the neural responses associated with such disorders. To date, studies indicate that parenthood is a period of enhanced brain plasticity within brain areas critical for cognitive and social processing and that both parenting experience and gestational-related factors can prime such plasticity.

Characterizing the Brain Structural Adaptations Across the Motherhood Transition

Women that become mothers face notable physiological adaptations during this life-period. Neuroimaging studies of the last decade have provided grounded evidence that women's brains structurally change across the transition into motherhood. The characterization of this brain remodeling is currently in its early years of research. The current article reviews this scientific field by focusing on our longitudinal (pre-to-post pregnancy) Magnetic Resonance Imaging (MRI) studies in first-time parents and other longitudinal and cross-sectional studies of parents. We present the questions that are currently being answered by the parental brain literature and point out those that have not yet been explored. We also highlight potential confounding variables that need to be considered when analyzing and interpreting brain changes observed during motherhood.

Early life maltreatment affects intrinsic neural function in mothers

Early life maltreatment (ELM) has an impact on brain functions involved in parenting and is associated with impaired maternal sensitivity. Here, we investigated the influence of ELM on intrinsic neural function and its associations with maternal sensitivity in mothers without a current episode of a mental disorder. Twenty-seven mothers with ELM and 29 mothers without ELM were examined using resting-state functional magnetic resonance imaging, followed by Amplitude of Low Frequency Fluctuations, regional homogeneity and seed-based functional connectivity analyses. Videotaped interactions between mothers and their school-aged children were conducted to assess maternal sensitivity based on the Emotional Availability Scales. Regional and functional connectivity measures were used to investigate associations between intrinsic activity and emotional availability. Mothers with ELM showed reduced maternal sensitivity and lower intrinsic neural activity in the right superior frontal gyrus, the left precuneus, the left middle occipital gyrus, and the parietal cortex (left angular and right supramarginal gyrus) compared to mothers without ELM (p < .001, whole-brain). Amplitude of Low Frequency Fluctuations in the superior frontal gyrus was positively associated with maternal sensitivity across all participants (p = .002). The data suggest a behavioral and neural signature of ELM even in currently mentally healthy mothers. In particular, effects of ELM were found in distinct brain regions involved in social cognition and executive control. These ELM-related alterations may be associated with maternal behavior.

Fathers' Involvement in Early Childcare is Associated with Amygdala Resting-State Connectivity

Becoming a parent requires new skills and frequent task switching during daily childcare. Little is known about the paternal brain during the transition to fatherhood. The present study examined intrinsic neuronal network connectivity in a group of first-time expectant and new fathers (total N = 131) using amygdala seed-based resting-state functional connectivity analysis. Furthermore, we examined the association between paternal involvement (i.e. hours spent in childcare and real-time push notifications on smartphone) and connectivity within the parental brain network in new fathers. There were no significant differences in functional connectivity between expectant and new fathers. However, results show that in new fathers, time spent in childcare was positively related to amygdala connectivity with the supramarginal gyrus, postcentral gyrus and the superior parietal lobule—all regions within the cognition/mentalizing network that have been associated with empathy and social cognition. Our results suggest that fathers’ time investment in childcare is related to connectivity networks in the parental brain.

Postpartum Stress and Neural Regulation of Emotion among First-Time Mothers

Early parenting relies on emotion regulation capabilities, as mothers are responsible for regulating both their own emotional state and that of their infant during a time of new parenting-related neural plasticity and potentially increased stress. Previous research highlights the importance of frontal cortical regions in facilitating effective emotion regulation, but few studies have investigated the neural regulation of emotion among postpartum women. The current study employed a functional neuroimaging (fMRI) approach to explore the association between perceived stress, depressive symptoms, and the neural regulation of emotion in first-time mothers. Among 59 postpartum mothers, higher perceived stress during the postpartum period was associated with less self-reported use of cognitive reappraisal in everyday life, and greater use of emotion suppression. While viewing standardized aversive images during the Emotion Regulation Task (ERT), mothers were instructed to experience their natural emotional state (Maintain) or to decrease the intensity of their negative emotion by using cognitive reappraisal (Reappraise). Whole-brain analysis revealed a two-way interaction of perceived stress x condition in the right dorsolateral prefrontal cortex (DLPFC) at p < .05 cluster-wise corrected, controlling for postpartum months and scanner type. Higher levels of perceived stress were associated with heightened right DLPFC activity while engaging in cognitive reappraisal versus naturally responding to negative stimuli. Higher right DLPFC activity during Reappraise versus Maintain was further associated with elevated parenting stress. Findings suggest that stress and everyday reappraisal use is reflected in mothers' neural regulation of emotion and may have important implications for their adaptation to parenthood.

Significant increases of the amygdala between immediate and late postpartum: Pronounced effects within the superficial subregion

Research exploring the underlying neuroanatomical correlates of early motherhood seems to suggest that the period after giving birth is marked by tissue increases in the mother's brain. While some studies point to the amygdala as one of the areas undergoing postpartum changes, existing analyses did not discriminate between the different subregions of this functionally heterogeneous structure. Thus, to further extend this understudied field of research and to better understand the potential role of the amygdala when transitioning to motherhood, we applied an advanced region-of-interest technique that enabled us to analyze the amygdala as a whole as well as its different subareas, specifically the left and right centromedian (CM), laterobasal (LB), and superficial (SF) regions. Comparing the brains of 14 healthy women between immediate postpartum (within 1-2 days of childbirth) and late postpartum (at 4-6 weeks after childbirth), we revealed increases of the amygdala. However, effects manifested differentially across subareas, with particularly strong effects for the SF region, moderate effects for the CM region, and no effects for the LB region. These findings might reflect region-specific adaptations of the mother's brain tuning into the distinct and ever-changing needs of a newborn, either as a cause for it or as a consequence thereof.

Neuroprotective Effects of Motherhood on Brain Function in Late Life: A Resting-State fMRI Study

The maternal brain undergoes structural and functional plasticity during pregnancy and the postpartum period. Little is known about functional plasticity outside caregiving-specific contexts and whether changes persist across the lifespan. Structural neuroimaging studies suggest that parenthood may confer a protective effect against the aging process; however, it is unknown whether parenthood is associated with functional brain differences in late life. We examined the relationship between resting-state functional connectivity and number of children parented in 220 healthy older females (73.82 ± 3.53 years) and 252 healthy older males (73.95 ± 3.50 years). We compared the patterns of resting-state functional connectivity with 3 different models of age-related functional change to assess whether these effects may be functionally neuroprotective for the aging human parental brain. No relationship between functional connectivity and number of children was obtained for males. For females, we found widespread decreasing functional connectivity with increasing number of children parented, with increased segregation between networks, decreased connectivity between hemispheres, and decreased connectivity between anterior and posterior regions. The patterns of functional connectivity related to the number of children an older woman has parented were in the opposite direction to those usually associated with age-related cognitive decline, suggesting that motherhood may be beneficial for brain function in late life.

How stress can influence brain adaptations to motherhood

Research shows that a woman's brain and body undergo drastic changes to support her transition to parenthood during the perinatal period. The presence of this plasticity suggests that mothers' brains may be changed by their experiences. Exposure to severe stress may disrupt adaptive changes in the maternal brain and further impact the neural circuits of stress regulation and maternal motivation. Emerging literature of human mothers provides evidence that stressful experience, whether from the past or present environment, is associated with altered responses to infant cues in brain circuits that support maternal motivation, emotion regulation, and empathy. Interventions that reduce stress levels in mothers may reverse the negative impact of stress exposure on the maternal brain. Finally, outstanding questions regarding the timing, chronicity, types, and severity of stress exposure, as well as study design to identify the causal impact of stress, and the role of race/ethnicity are discussed.

Neurobiological changes during the peripartum period: implications for health and behavior

Pregnancy and the transition to parenthood is an important period marked by dramatic neurobiological and psychosocial changes that may have implications for the health of women and offspring. Although human and non-human animal research suggests that the brain undergoes alterations during the peripartum period, these changes are poorly understood. Here, we review existing research, particularly human neuroimaging and psychophysiological research, to examine changes in brain structure and function during the peripartum period and discuss potential implications for the health of women and offspring. First, we discuss the potential causes of these changes across pregnancy, including physiological and psychosocial factors. Next, we discuss the evidence for structural and functional changes in the brain during pregnancy and into the postpartum period, noting the need for research conducted prospectively across human pregnancy. Finally, we propose potential models of individual differences in peripartum neurobiological changes (i.e. hypo-response, typical response, hyper-response) and emphasize the need to consider trajectories of change in addition to pre-existing factors that may predict maternal adjustment to parenthood. We suggest that the consideration of individual differences in neurobiological trajectories across pregnancy may contribute to a better understanding of risk for negative health and behavior outcomes for women and offspring.

Intrinsic brain activity associated with eye gaze during mother-child interaction

Mother-child interactions impact child social development and psychological health. This study focused on eye-gaze interactions, especially eye contact as synchronized gaze, which is an important non-verbal communication tool in human interactions. We performed brain-image analysis of mothers and children using resting-state functional magnetic resonance imaging and quantitatively evaluated the quality of mother-child interactions using the Interaction Rating Scale to investigate how it is related to the frequency of mother-child eye contact. As a result, we found a positive correlation between the frequency of eye gaze and the right anterior insula (AI) or middle frontal gyrus in children and a positive correlation with the anterior cingulate cortex (ACC) and precuneus/cuneus in mothers. Especially, when eye contact was made, the association with the right AI in children and ACC in mothers was retained, suggesting the involvement of the salience network responsible for modulating internal and external cognition. In addition, the frequency of eye contact was positively associated with the quality of mother-child interaction. These results suggest that the salience network is a major candidate for the neural basis involved in maintaining efficient eye contact and that it plays an important role in establishing positive mother-child interactions.

The peripartum human brain: Current understanding and future perspectives

The peripartum period offers a unique opportunity to improve our understanding of how dramatic fluctuations in endogenous ovarian hormones affect the human brain and behavior. This notwithstanding, peripartum depression remains an underdiagnosed and undertreated disorder. Here, we review recent neuroimaging findings with respect to the neuroplastic changes in the maternal brain during pregnancy and the postpartum period. We seek to provide an overview of multimodal neuroimaging designs of current peripartum depression models of hormone withdrawal, changes in monoaminergic signaling, and maladaptive neuroplasticity, which likely lead to the development of a condition that puts the lives of mother and infant at risk. We discuss the need to effectively integrate the available information on psychosocial and neurobiological risk factors contributing to individual vulnerability. Finally, we propose a systematic approach to neuroimaging the peripartum brain that acknowledges important co-morbidities and variation in disease onset.