An experimental study on mother-infant skin-to-skin contact in full-terms

In premature infants, daily skin-to-skin contact (SSC) has various beneficial effects on the health of the infant and the mother. These beneficial effects might extend to full-term infants. This experimental within-subject study examines the immediate effects of SSC on full-terms’ cortisol physiology during SSC and subsequent physiological and behavioral reactions to a mild stressor (a bathing session). Additionally, the effects of SSC on the quality of maternal behavior are examined.Between 5 and 7 weeks postpartum, 17 full-term infant-mother dyads were visited at home twice. During one home visit, a bathing session was proceeded by 50 min of mother-infant SSC, while during the other visit the bathing session was proceeded by 50 min of the infant resting alone. The order of the home visits was counterbalanced. Infant salivary cortisol measures were taken to measure the cortisol response to the experimental condition (SSC versus solitary resting) and the bathing session. Furthermore, infant behavioral distress and the quality of maternal behavior during the bathing session were scored from videotapes.Two-way within-subject repeated measures ANOVA’s showed that, when compared to solitary resting, full-terms’ cortisol concentrations significantly decreased during SSC, followed by higher cortisol reactivity in response to the subsequent bathing session. No effects of SSC on infant behavioral distress and maternal caregiving behavior were found. Apparently, a single session of mother-infant SSC can affect infant cortisol physiology in full-term infants. Future SSC research is needed to investigate the neurobiological mechanisms and dose-response relations in full-term infants.     

Enhancing effects of acute psychosocial stress on priming of non-declarative memory in healthy young adults

Social stress affects cognitive processes in general, and memory performance in particular. However, the direction of these effects has not been clearly established, as it depends on several factors. Our aim was to determine the impact of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) reactivity to psychosocial stress on short-term non-declarative memory and declarative memory performance. Fifty-two young participants (18 men, 34 women) were subjected to the Trier Social Stress Task (TSST) and a control condition in a crossover design. Implicit memory was assessed by a priming test, and explicit memory was assessed by the Rey Auditory Verbal Learning Test (RAVLT). The TSST provoked greater salivary cortisol and salivary alpha-amylase (sAA) responses than the control task. Men had a higher cortisol response to stress than women, but no sex differences were found for sAA release. Stress was associated with an enhancement of priming but did not affect declarative memory. Additionally, the enhancement on the priming test was higher in those whose sAA levels increased more in response to stress (r(48)?=?0.339, p?=?0.018). Our results confirm an effect of acute stress on priming, and that this effect is related to SNS activity. In addition, they suggest a different relationship between stress biomarkers and the different memory systems.     

Chronic stress in the mother-infant dyad: Maternal hair cortisol,infant salivary cortisol and interactional synchrony

Stress physiology is shaped by early experience, with enduring effects on health. The relation of chronic maternal physiological stress, as indexed by hair cortisol, to infants’ stress systems and to mother-infant interaction quality has not been established. We examined maternal hair and salivary cortisol, six-month-old infants’ salivary cortisol, and mother-infant interaction in 121 mother-infant dyads. High maternal hair cortisol was related to higher infant average salivary cortisol concentration. Maternal hair cortisol and bedtime salivary cortisol were both uniquely related to infant bedtime salivary cortisol. Mothers with higher hair cortisol were more intrusive and had lower positive engagement synchrony with their infants. Maternal intrusiveness moderated the association of maternal hair cortisol and infant salivary cortisol, such that maternal hair and infant average salivary cortisol were related only when mothers were more intrusive. Maternal chronic physiological stress may upregulate infants’ developing stress systems, particularly in the context of lower mother-infant interaction quality.     

儿童版特里尔社会应激测试对儿童唾液皮质醇、唾液α-淀粉酶和情绪的影响

研究以150名五、六年级的学生为被试,考察儿童版特里尔社会应激测试（TSST-C）对儿童客观生理反应（唾液皮质醇和唾液α-淀粉酶）和主观情绪反应的影响。结果发现,TSST-C引起了儿童显著的应激反应,包括皮质醇和唾液α-淀粉酶水平的升高,以及主观消极情绪（如焦虑和紧张）的增加,这表明TSST-C在中国儿童中的适用情况良好,能够有效诱发儿童的应激反应。同时,研究也发现,皮质醇反应和唾液α-淀粉酶反应不存在相关,生理反应和情绪反应之间也不存在相关。     

Neuroendocrine stress responses to an oral academic examination: No strong influence of sex, repeated participation and personality traits

Public speaking tasks have been widely used as laboratory stressors in human research. Fewer studies have investigated similar real life situations like oral examinations and results have been inconsistent. The present study investigated salivary cortisol (as a marker of hypothalamus-pituitary-adrenal (HPA) activity) and salivary alpha-amylase (sAA as a marker of sympathetic nervous system (SNS) activity) within the context of a university examination. Subjects were 40 undergraduate students who participated in an oral examination. Of these, 20 also participated in a second examination within a few weeks. Cortisol and sAA were measured immediately before and after the examination and on a control day. Additionally, subjects filled out personality questionnaires. A strong anticipatory increase in salivary cortisol and sAA as well as more modest further increases between the pre- and post-measurements were detected during the examination. Sex or oral contraceptive use had no influence on either measure. In addition, no significant differences between the first and second examination were observed. The findings indicate the neuroendocrine stress responses to laboratory stressors and to heralded real life stressors as well as the modulatory variables involved differ from each other.     

Cortisol and Children’s Adjustment: The Moderating Role of Sympathetic Nervous System Activity

We examined relations among cortisol, markers of sympathetic nervous system (SNS) activity (including salivary alpha-amylase and skin conductance level), and children's adjustment. We also tested the Bauer et al. (Journal of Developmental and Behavioral Pediatrics, 23(2), 102-113, 2002) hypothesis that interactions between the SNS and cortisol would be associated with internalizing and externalizing problems. Saliva samples were obtained from 8- to 9-year-olds before and after a laboratory assessment battery, and were assayed for cortisol and alpha-amylase (sAA). Basal skin conductance level (SCL) was measured during resting conditions. Parents reported on child adjustment. Interactions between basal SNS and cortisol levels explained moderate amounts of unique variance in children's externalizing and internalizing problems. More specifically, higher basal cortisol levels were positively associated with higher internalizing and externalizing problems among children with higher SNS activity, as compared to children with lower SNS activity. Findings underscore the utility of including information about the coordination between hypothalamic-pituitary-adrenal (HPA) and SNS activity in biosocial models of atypical child development.     

Culture,carrying, and communication: Beliefs and behavior associated with babywearing

Ethnographic research suggests mother-infant physical contact predicts high levels of maternal responsiveness to infant cues, yet it is unclear whether this responsiveness is driven by the act of physical contact or by underlying beliefs about responsiveness. We examine beliefs and behavior associated with infant carrying (i.e., babywearing) among U.S. mothers and experimentally test the effect of mother-infant physical contact on maternal responsiveness. In Study 1 (N = 23 dyads), babywearing mothers were more likely to interact contingently in response to infant cues than non-babywearing mothers during an in-lab play session. In Study 2 (N = 492 mothers), babywearing predicted maternal beliefs emphasizing responsiveness to infant cues. In Study 3 (N = 20 dyads), we experimentally manipulated mother-infant physical contact in the lab using a within-subjects design and found that babywearing increased maternal tactile interaction, decreased maternal and infant object contact, and increased maternal responsiveness to infant vocalizations. Our results motivate further research examining how culturally-mediated infant carrying practices shape the infant’s early social environment and subsequent development.     

The role of oxytocin in early mother-infant interactions: Variations in maternal affect attunement

The aim of the present research was to investigate the relationship between oxytocin and maternal affect attunement, as well as the role of affect attunement in the relationship between oxytocin and infant social engagement during early mother-infant interactions. Forty-three mother-infant dyads participated in the present study when infants were 4 months. They were observed during (1) a situation where no communication took place and (2) a natural interaction between mother and infant. During this procedure, three saliva samples from mothers and their infants were collected to determine their levels of oxytocin at different time points. Maternal affect attunement (maintaining attention, warm sensitivity) and infant interactive behaviors (gaze, positive, and negative affect) were coded during the natural interaction. Results indicated that overall maternal oxytocin functioning was negatively related to her warm sensitivity, while infant oxytocin reactivity together with maternal affect attunement were associated with infant positive social engagement with their mothers. Specifically, infant oxytocin reactivity was significantly related to their gazes at mother, but only for infants of highly attuned mothers. These results point to the complex role oxytocin plays in parent-infant interactions while emphasizing the need to analyze both overall oxytocin functioning as well as reactivity as different indices of human affiliative behavior.     

Adolescent Personality: Associations With Basal,Awakening, and Stress‐Induced Cortisol Responses

The purpose of the present study was to investigate the associations between personality facets and hypothalamic‐pituitary‐adrenal (HPA) axis functioning. Previous studies have mainly focussed on stress‐induced HPA‐axis activation. We hypothesized that other characteristics of HPA‐axis functioning would have a stronger association with personality based on the neuroendocrine literature. Data (n = 343) were used from the TRacking Adolescents' Individual Lives Survey (TRAILS), a large prospective cohort study of Dutch adolescents. We studied the association between facets of Neuroticism, Extraversion, and Conscientiousness and basal cortisol, the cortisol awakening response (CAR), and four measures of stress‐induced HPA‐axis activity. Basal cortisol levels were related to facets of all three personality traits. The CAR and stress‐induced cortisol were not related to personality. Possibly due to its more trait‐like nature, basal cortisol seems more informative than stress‐induced cortisol when investigating trait‐like characteristics such as personality facets.     

Responsiveness in mother-infant social interactions among immigrant and nonmigrant families: Japanese,South Korean,South American,and European American

A culture learning perspective motivated the present study of the acculturation of responsiveness in mother-infant interactions. Several conceptual and analytic features of responsiveness in mother-infant social interactions were examined: Temporal contingency, mean differences in responsiveness among and within dyads, attunement of mother and infant responsiveness withing dyads, and the influence of acculturation on individual responsiveness. Methodologically, acculturation was assessed at group and individual levels in immigrant Japanese, South Korean, and South American dyads in comparison with nonmigrant dyads in their respective cultures of origin (Japan, South Korea, and South America) and their single common culture of destination (United States). In total, 408 mothers and their 5½-month-old infants were observed in the naturalistic setting of the home, and observations were coded for mothers’ speech to infant, social play, and encouraging her infant to look at her, and infants’ looking at mother and nondistress vocalizations. Odds ratios were then generated for mother and infant responsiveness in four types of social interactions: Mother speaks to infant and infant looks at mother (Mother Speak/Infant Attend), mother plays with infant and infant looks at mother (Mother Play/Infant Attend), mother plays with infant and infant vocalizes (Mother Play/Infant Vocalize), and mother encourages infant to look at her and infant vocalizes (Mother Encourage/Infant Vocalize). Five key findings emerged. Specifically, mother and infant responsiveness in Mother Speak/Infant Attend interactions were temporally contingent in all cultures. Mean differences in responsiveness among cultures emerged, and within dyads infants were more responsive than their mothers in Mother Speak/Infant Attend interactions. Mother and infant responsiveness in Mother Speak/Infant Attend interactions were attuned in all cultures. Responsiveness in Mother Play/Infant Vocalize interactions showed acculturation effects at the individual level. Implications of these findings for understanding the development of responsiveness in social interactions and acculturation in immigrant families are discussed.     

SHALL WE DANCE? MUSIC AS A PORT OF ENTRANCE TO MATERNAL–INFANT INTERSUBJECTIVITY IN A CONTEXT OF POSTNATAL DEPRESSION

The present study introduces the concept of a mother–infant group therapy that makes use of music, singing, and moving to establish maternal–infant intersubjectivity. It was conducted in a residential mother–baby unit for mothers with postnatal depression and their infants over a 5‐week period. Maternal–infant intersubjectivity of four dyads in relation to the group dynamics were microanalyzed for Sessions 1 and 5. We made within‐session (i.e., beginning–middle–end) and between‐session (Session 1 vs. Session 5) comparisons for the number of intersubjectivity moments (ISMs), total time of intersubjectivity (IST), and the mean duration of ISMs on a dyadic (i.e., own mother/infant involved) and a nondyadic level (i.e., own mother/infant not involved). In addition, three ISM levels (degree of group contribution) were distinguished. The results indicated a significant increase of ISMs/IST from Session 1 to Session 5. Within‐session analyses showed that ISMs/IST significantly decreased through Session 1 and remained stable throughout Session 5. Intersubjectivity occurred mainly on ISM Level 1 during Session 1 and on ISM Level 3 during Session 5, suggesting increased dyadic autonomy and self‐efficacy. The results are discussed in relation to the musical characteristics of mother–infant dyads, music improvisation techniques, group processes, and intersubjective development.     

Similarities and differences in mothers' and observers' ratings of infant security on the Attachment Q-Sort

This study examined the similarities and differences in maternal and observer Attachment Behavior Q-Sort ratings (AQS; Waters, 1995) and their relations to dimensions of the developmental ecology - maternal sensitivity, infant irritability, parental stress and psychosocial risk. Data was gathered from low risk (adult mothers; N=44) and high risk mother-infant dyads (adolescent mothers; N=83) when infants were aged 6, 10 and 15 months old, attachment being assessed at 15 months by both mothers and independent observers. A common factor was extracted from both sorts and served to operationalize the similarities between mother and observer ratings. Regressions were conducted to extract maternal and observer AQS scores that were unrelated to each other to represent the difference between the two sorts. Correlation analyses indicated that the common AQS factor was moderately linked to maternal sensitivity and parental stress, and showed a weak association to psychosocial risk and infant irritability. Residual maternal scores showed greater correlations with infant irritability and parental stress than did observer residual scores. Observer scores showed a greater correlation with psychosocial risk than maternal scores. Results suggest that common AQS variance presents a pattern of associations with ecological variables that is coherent with attachment research. Variance related to irritability, stress and risk appear to drive the differences between maternal and observer observations.     

The association between maternal interaction and infant cortisol stress reactivity among preterm and full term infants at 4 months adjusted age

The purpose of this study was to assess the association between maternal interactive behavior and infant cortisol stress reactivity in response to the Still Face paradigm (SF) in a cohort of four-month old infants (adjusted age) born preterm (<32 weeks gestation, N = 22) compared with infants born full term (>37 weeks gestation, N = 28). Infant cortisol reactivity was calculated as area under the curve (AUC) from baseline to the third cortisol sample (30 min post-SF) using the trapezoidal rule, while the percent of time mothers spent using a contingent interaction style was measured (0–100%) during episodes 1 (Play; baseline), 3 (Reunion#1), and 5 (Reunion#2) while mother-infant dyads participated in the SF paradigm. We hypothesized that because infants born preterm are at increased risk for dysregulation, they would show, compared to full-term infants, a blunted stress response, involving under-responsiveness. We found blunted cortisol stress reactivity among the preterm infants. We also found that mothers of preterm infants demonstrated less contingent maternal interaction during Renion#1 of the SF; and that contingent maternal interaction at Reunion#2 of the SF was protective against cortisol stress reactivity in response to the SF. However, we did not find that the influence of maternal interaction on cortisol reactivity was moderated by gestational age group (full term vs preterm): the association between contingent maternal interaction and stress reactivity was similar for both gestational groups across episodes. In order to improve self-regulation and longer term social and cognitive developmental outcomes in medically at-risk infants, future research is warranted to determine how these findings relate to infants’ stress reactions in naturalistic settings, and the directionality and temporal relationship between cortisol stress responses and maternal interactive behavior.     

Better not to deal with two tasks at the same time when stressed? Acute psychosocial stress reduces task shielding in dual-task performance

A major control demand in successful dual-task performance is the task-specific separation of task-goal representations and of the related stimulus-response translation processes. In the present study, we investigated how these cognitive control processes of task shielding are affected by acute psychosocial stress. Fifty-six healthy participants were exposed to either an acute psychosocial stressor (the Trier Social Stress Test) or a standardized control situation prior to a dual task. Task shielding was assessed by analyzing the interference of Task 2 processing on prioritized Task 1 performance. Following successful stress induction, as indicated by increases in salivary α-amylase (sAA) and cortisol that reflect increases in sympathetic nervous system and hypothalamus-pituitary-adrenal (HPA) axis activity, respectively, stressed individuals displayed reduced task shielding relative to controls. This result was further substantiated by a correlation between treatment-related increase in cortisol, but not sAA, and between-task interference, suggesting a potential role of the HPA stress response for the development of the observed effects. As an additional finding, when the volunteers were categorized with regard to their action-state orientation, their orientation did not interact with stress but did reveal generally increased between-task interference, and thus inferior task shielding, for state-oriented as compared to action-oriented individuals.     

Does Sex Matter? The Moderating Role of Sex on the Relationship Between Stress Biomarkers and Cognition

We examined the moderating role of sex on the relationship between salivary cortisol and alpha-amylase (sAA) and a diverse battery of cognitive outcomes including measures of working memory capacity, executive functioning, and prospective memory in addition to a more traditional memory measure (episodic memory). The final sample for the analyses included 144 participants (34 men and 110 women). Multiple regressions were performed to test the moderating role of sex on the stress biomarker-cognition relationship. For backward counting performance, higher cortisol levels were related to worse performance in men, but not women. Higher cortisol levels were also related to lower word recall, but only in men. Finally, men, but not women, had higher switching costs in the Trail Making task as levels of sAA rose. The results provide evidence that sex moderates the stress biomarker-cognition relationship in a variety of cognitive outcomes. Although not part of the primary analysis, sAA and cortisol interacted such that increased sAA levels were only negatively related to backward counting performance when cortisol levels were low. The findings are discussed primarily in terms of biological sex differences in the stress response.     

Parent-Training with Kangaroo Care Impacts Infant Neurophysiological Development & Mother-Infant Neuroendocrine Activity

A randomized control trial was conducted to investigate the effects of skin-to-skin, chest-to-chest contact (kangaroo care, KC) in mother-infant dyads on patterns of infant brain activity and associated mother-infant neurohormone releases. 33 mother-infant dyads participated during pregnancy (29–38 weeks gestation), at neonatal and 3-month periods. Overall, analyses indicated that: 1) infants in the KC group showed left frontal brain activation patterns (asymmetry and coherence) associated with KC training; 2) KC produced moderate to large increases in oxytocin levels; and 3) KC yielded moderate decreases in cortisol reactivity. Findings suggest KC may garner favorable neuro-maturational and neurobiological outcomes for dyads.     

Endocrine and emotional response to exclusion among women and men; cortisol,salivary alpha amylase,and mood

Background and Objectives: Social exclusion is ubiquitous and painful. Evolutionary models indicate sex differences in coping with social stress. Recent empirical data suggest different sex patterns in hypothalamic–pituitary–adrenal (HPA) and sympathetic–adrenal–medullary (SAM) reactivity. The present study sought to test this hypothesis.

Design: We examined differences in endocrine and emotional response to exclusion by using a virtual ball tossing paradigm (Cyberball). Saliva samples and mood ratings were collected to reflect levels before, and repeatedly following, exclusion.

Methods: The sample included 21 women and 23 men. Cortisol and salivary alpha amylase (sAA), biomarkers of the HPA and SAM systems, respectively, were used as indices of two arms of stress response.

Results: Following exclusion, all participants experienced mood worsening followed by mood improvement, with men reporting less distress than women. Women evinced decline in cortisol following the Cyberball task, whereas men’s cortisol levels showed a non-significant rise, and then decline, following exclusion.

Conclusions: Our results concur with previous findings showing SAM reactivity to be gender-neutral and HPA reactivity to be gender-divergent. Additional studies are needed to examine sex-specific response to social exclusion. Implications for individual differences in recovery from stress are discussed.     

The father-daughter dance: the relationship between father-daughter relationship quality and daughters' stress response

The goal of the study was to determine whether father-daughter relationship quality is related to activity of the hypothalamic-pituitary-adrenal (HPA) axis (salivary cortisol) and autonomic nervous system (salivary alpha-amylase, sAA) in late adolescence-emerging adulthood during peer interactions. In the 1st study, reported father-daughter relationships characterized by rejection, chaos, and coercion had lower morning cortisol levels and were temperamentally more sensitive to emotional changes. In the 2nd study, young women who reported father-daughter relationships characterized by warmth, autonomy, support, and structure had lower pretask cortisol levels, and they had attenuated cortisol responses to problem discussion with a friend. In contrast, those who reported father-daughter relationships characterized by rejection, chaos, and coercion had higher pretask cortisol levels, had elevated cortisol in response to problem discussion with a friend, and were more likely to self-disclose about psychosocial stressors. No differences were observed between reported father-daughter relationship quality and sAA levels or task-related reactivity. The findings suggest that father-daughter interactions potentially influence both social cognition and HPA reactivity to developmentally salient stressors in young women.     

Perceived stress and physiological dysregulation in older adults

We use a population-based representative sample of older Taiwanese to investigate links between respondents' perceived levels of stress and a broad set of biological measures. These biomarkers were collected at a single time (2000) and reflect sympathetic nervous system (SNS)-activity, hypothalamo-pituitary-adrenal (HPA)-activity, immune function, cardiovascular function, and metabolic pathways. We model the relationship between perceived stress and (1) extreme values for each of 16 individual biological indicators; and (2) a measure of cumulative physiological dysregulation based on the full set of biomarkers. We consider two measures of perceived stress, one derived from the 2000 interview and the second based on data from three interviews (1996-2000). Age and sex-adjusted models reveal significant associations between measures of perceived stress and extreme values of cortisol, triglycerides, interleukin-6 (IL-6), dehydroepiandrosterone sulphate (DHEAS) and fasting glucose. Examined individually, numerous biomarkers, including those pertaining to blood pressure and obesity, are not significantly related to perceived stress. Jointly, however, the measure of cumulative physiological dysregulation is associated with both the level of perceived stress at a given time and to a longitudinal measure of perceived stress. Some results suggest that the relationship between level of perceived stress and physiological response is stronger for women than men.     

Experimental manipulation of maternal proximity during short sequences of sleep and infant calming response

This study aimed to understand how different mother-infant sleeping arrangements impact infants’ self-regulation, particularly their calming response. Thus this study investigated the effect of three prevalent mother-infant sleeping arrangements, co-sleeping (CS), sleeping beyond arm’s length from their mother (BAL), and solitary sleeping (SS), on infants’ physiological calming through self-regulation during a nap session in 24 infants (50% female, M = 1.85 months SD = 0.93 months), who were identified as either regular co-sleepers with their mothers, infants who slept in the BAL sleeping arrangement from their mother, and infants who are solitary sleepers (SS). The effect of all three sleeping conditions amongst all the three types of infants with different habitual sleeping arrangements was assessed. All infants spent 10 min (2 × 5 min sessions) in each sleeping condition (CS, BAL, SS) during which electrocardiographic recordings were collected to obtain interbeat intervals (IBI) and rMSSD, a measure of heart rate variability (HRV) an index of physiological calming, maintained by the parasympathetic pathway involved in self-regulation. Infants who regularly co-slept with their mothers had the highest IBI, indicating greater physiological calming and self-regulation across all sleeping arrangement conditions (CS, BAL, SS), followed by infants who regularly slept in the BAL sleeping arrangement from their mothers. IBI was lowest amongst regular solitary sleepers, potentially indicating physiological stress due to mother-infant separation. However, HRV indices during the sleeping arrangements (especially across regular solitary sleepers) were inconclusive as to whether the lack of change in HRV across all sleeping conditions was due to physiological stress responses or greater physiological regulation. This study is the first to investigate the effect of manipulated and habitual mother-infant sleeping arrangements on infant physiological calming.