Separation distress and attachment in surrogate-reared squirrel monkeys.

Surrogate-reared infant squirrel monkeys were exposed to various conditions of separation from their surrogate. Infants showed significant increases in plasma levels of cortisol when they were placed in an unfamiliar environment during the separation period. Changes in behavior, but not cortisol, were observed under conditions in which the surrogate was removed and the infant left in the home cage. These results differ from those previously obtained with mother-reared infants. It is concluded that surrogate-reared infant squirrel monkeys do not show the same separation response or attachment to their rearing figure as do mother-reared infants.     

Physiological correlates of performance. Case study of a world-class rower

This report describes the changes in physiological capacity of a heavy-weight rower who obtained seven medals in World Championships and Olympic Games. The investigation was carried out over the last 6 years of the rower’s international competition career in comparison with peer champions, and the following 4 years. Over the first period, maximal oxygen uptake () remained above 6 l min⁻¹ which is an outstanding value. The training load measured over the last 18 months of the period increased from 119 to 142 km wk⁻¹ of rowing. Four years after the international competition period, had only declined by 3.6% although the training load had declined by 35%. These data suggest that the ability of this rower to compete at top level for years was related to ability to maintain an outstanding . Gross efficiency and ability to rely on anaerobic glycolysis did not emerge as relevant factors.     

Predicting children's separation anxiety at age 6: the contributions of infant-mother attachment security, maternal sensitivity, and maternal separation anxiety

The purpose of the present investigation was to examine the precursors and familial conditions which sustain school-aged children's separation anxiety. In a prospective, longitudinal study of 99 mother-child dyads, infancy measures of infant-mother attachment security, maternal separation anxiety, and maternal sensitivity were used to predict children's self-reported symptoms of separation anxiety at age 6. Insecurely attached children reported more separation anxiety than securely attached children. Insecure-ambivalent children reported marginally more separation anxiety than securely attached children, but not more than insecure-avoidant attached children. Regression analysis showed infant-mother attachment security and mother's sensitivity added uniquely to the prediction of children's separation anxiety, but mother's separation anxiety did not. Mediation tests show that the effect of mother's separation anxiety on children's separation anxiety may be mediated by maternal sensitivity. Research and clinical implications are discussed.     

Physiological correlates of maternal-offspring behaviour in sheep: a factor analysis.

The onset of maternal behaviour in sheep is controlled by levels of oestrogen and progesterone in gestation and the release of oxytocin during delivery. Factor analysis was used to investigate the relationships between maternal behaviour, offspring behaviour, and maternal ovarian hormone levels during gestation in sheep. Ewes gave birth to lambs following embryo transfer between two breeds (Suffolk and Scottish Blackface), which differ in their expression of maternal behaviour. Plasma oestradiol-17beta concentration was significantly higher in Blackface ewes in the last 6 weeks of pregnancy, whereas plasma progesterone was higher in Suffolk ewes in early and mid gestation. Factor analysis revealed three factors that accounted for 50% of the total variation between variables. Factor 1 described lamb activity and had positive loadings for lamb behavioural latencies immediately postpartum, and negative loadings for sucking frequency. Factor 2 described some aspects of ewe maternal behaviour, and had positive loadings for ewe-lamb separation and lamb vocalisation, and negative loadings for ewe grooming behaviour and plasma oestradiol concentration. Factor 3 described ewe and lamb-sucking interactions, and had positive loadings for ewe moving as the lamb made sucking attempts, and negative loadings for ewe and lamb vocalisation. Factor 1 scores were significantly affected by lamb breed: Suffolk lambs received positive scores, indicating a longer latency to right and stand, whereas Blackface lambs had negative scores. Maternal progesterone concentration was significantly correlated with Factor 1 scores. Factor 2 and 3 scores were significantly affected by ewe breed. This study has shown that there are two behavioural axes to maternal behaviour in sheep, and that maternal oestradiol concentration is related to affiliative behaviours (e.g., grooming) but only weakly to ewe responsiveness to lamb-sucking attempts.     

The role of maternal attachment in children's attachment and cognitive executive functioning: A preliminary study

The influence of maternal attachment on children's attachment and executive functioning skills through maternal sensitivity and decentered tutoring were studied in 40 middle-class mother–child dyads. Infant attachment security in the Strange Situation Procedure was related to maternal attachment security, evaluated with the Adult Attachment Interview. When the children were six–seven months of age, maternal sensitivity was evaluated. When the child was six years old, maternal decentered tutoring and the children's executive functioning were evaluated. Regression analyses indicated that maternal tutoring accounted for the association between maternal attachment and child cognitive functioning, whereas maternal sensitivity accounted for the association between maternal and child attachment.     

Analysis of the disruption of maternal social bonds in Octodon degus: separation distress in restricted reunion tests

Octodon degus is a social caviomorph species that exhibits strong social bonds and robust distress responses to maternal separation. To understand the impact of early social isolation on social motivation, we investigated how social isolation during infancy, associated with repeated restricted interactions with mother and siblings, altered social motivation in young degus. In Experiment 1, three treatments were compared: complete isolation (ISOLATED group), nearly complete isolation, with daily half hour partition-restricted reunions with the mother and siblings (RESTRICTED group), and social-housing with the mother and siblings (FAMILY group). After 10 days of treatment, all subjects underwent a 5-day choice test between mothers and unfamiliar females. During the treatment period, the RESTRICTED animals emitted more isolation calls and spent more time close to the partition that separated them from mothers than ISOLATED animals. During the first social-choice day, FAMILY reared animals showed a preference for the mother for a few minutes, while the RESTRICTED animals preferred the mother for the whole session. Totally ISOLATED pups exhibited no social preferences. Since during successive testing periods the isolation calls decreased over the days, in Experiment 2 we investigated whether this decline was related to age or habituation to testing procedures. Animals were observed during a single exposure to isolation (ISOLATED) or restricted-reunion (RESTRICTED) at PND 21 and 31. The decrease of vocalizations was due to an age-effect. The findings clarify the nature of social bonds in degus.     

Physiological effects of separation and reunion in relation to attachment and temperament in young children

This study examined physiological effects of separation and reunion in a sample 3- to 6-year-old children. Using continuous ambulatory recording, changes in heart rate (HR), respiratory sinus arrhythmia (RSA), and pre-ejection period (PEP) were compared across the episodes of a separation-reunion procedure based on the strange situation. RSA decreased significantly over the course of the procedure as well as on separation from the parent and not the stranger, supporting that separation from the attachment figure elicited vagal withdrawal in young children. The absence of significant PEP effects suggest that the separation-reunion procedure, and more specifically separation from the parent, was not threatening enough to activate the sympathetic nervous system, even if children were insecure attached and inhibited with regard to strangers. Some of the variability in HR increases to reunion was explained by younger age. The findings highlight the role of the ANS as a regulatory process in the parent-child relationship.     

A longitudinal study of maternal attachment and infant developmental outcomes

Extant research has demonstrated that compared to adults with insecure attachment styles, more securely attached parents tend to be more responsive, sensitive, and involved parents, resulting in improved outcomes for their children. Less studied is the influence of a mother's attachment style on her attachment to her unborn child during pregnancy and the consequent developmental outcomes of the child during early childhood. Thus, the aim of this prospective longitudinal study was to examine the relationship between maternal–fetal attachment (MFA) during pregnancy and infant and toddler outcomes and the role of mothers' attachment style on early childhood developmental outcomes in an economically disadvantaged sample of women and their children. Gamma regression modeling demonstrated that an avoidant maternal attachment style (b?=?.98, 95 % CI [.97, .98], p?<?0.001) and post-partum depressive symptomatology (b?=?.97, 95 % CI [.96–.99], p?=?0.03) were significant predictors of early childhood development. Women demonstrating higher avoidant attachment styles and greater depressive symptomatology were more likely to have children demonstrating early childhood developmental delays than those women with less avoidant attachment styles and less depressive symptomatology. Furthermore, women reporting higher MFA during pregnancy had more secure attachment styles, and their children had more optimal early childhood development than those women reporting lower MFA and less secure attachment styles. Findings have implications for enhancing early intervention programs aimed at improving maternal and childhood outcomes. An earlier identification of disruptions in attachment may be beneficial in tailoring interventions focused on the mother–child dyad.     

Attachment security: a meta-analysis of maternal mental health correlates

This meta-analysis addresses the association between attachment security and each of three maternal mental health correlates. The meta-analysis is based on 35 studies, 39 samples, and 2,064 mother-child pairs. Social-marital support (r = .14; based on 16 studies involving 17 samples and 902 dyads), stress (r = .19; 13 studies, 14 samples, and 768 dyads), and depression (r = .18; 15 studies, 19 samples, and 953 dyads) each proved significantly related to attachment security. All constructs showed substantial variance in effect size. Ecological factors and approach to measuring support may explain the heterogeneity of effect sizes within the social-marital support literature. Effect sizes for stress varied according to the time between assessment of stress and assessment of attachment security. Among studies of depression, clinical samples yielded significantly larger effect sizes than community samples. We discuss these results in terms of measurement issues (specifically, overreliance on self-report inventories) and in terms of the need to study the correlates of change in attachment security, rather than just the correlates of attachment security per se.     

Exercise normalizes altered expression of proteins in the ventral hippocampus of rats subjected to maternal separation

Many studies have reported on the detrimental effects of early life adversity and the beneficial effects of exercise on brain function. However, the molecular mechanisms that underpin these various effects remain poorly understood. The advent of advanced proteomic analysis techniques has enabled simultaneous measurement of protein expression in a wide range of biological systems. We therefore used iTRAQ proteomic analysis of protein expression to determine whether exercise counteracts the detrimental effects of early life adversity in the form of maternal separation on protein expression in the brain. Rat pups were subjected to maternal separation from postnatal day 2 to 14 for 3 h day(-1) or normally reared. At 40 days of age, half of the rats in each group (maternal separation and normally reared) were allowed to exercise voluntarily (access to a running wheel) for 6 weeks and the remainder kept as sedentary control animals. At 83 days of age, rats were killed and the ventral hippocampus was dissected for quantitative proteomic (iTRAQ) analysis. The iTRAQ proteomic analysis identified several proteins that had been altered by maternal separation, including proteins involved in neuronal structure, metabolism, signalling, anti-oxidative stress and neurotransmission, and that many of these proteins were restored to normal by subsequent exposure to voluntary exercise in adolescence. Our data show that a broad range of proteins play a role in the complex consequences of adversity and exercise.     

A short-term longitudinal study of correlates and sequelae of attachment security in autism

In this short-term longitudinal study, 30 preschool-aged children with autism were first observed in Ainsworth’s Strange Situation Procedure and, separately, interacting with the primary caregiver in the home. One year later, each child completed both a developmental assessment and an observational assessment of empathic responding. Behaviors typical for children with autism were distinguished from behaviors suggestive of relationally based attachment disorganization. Forty-five percent of the children were classified as securely attached. The secure group demonstrated language skills superior to those of the insecurely attached group, concurrently and during the follow-up. Compared to parents of children who were insecurely attached, parents of securely attached children were rated as more sensitive. Compared to both organized insecure and disorganized children, secure children were rated as more responsive to an examiner’s apparent distress during the follow-up relative to their ratings at intake, whereas empathy ratings of children with insecure classifications did not increase. Importantly, attachment security was associated with empathy above and beyond the contribution of children’s language level. These results indicate that the sequelae of attachment security in autism may be similar to those documented for typically developing children.     

Molecular-genetic correlates of infant attachment: A cautionary tale

This paper advises caution in relation to the increasing interest in molecular-genetic association studies in developmental psychology based on a set of empirical examples from the NICHD Study of Early Child Care and Youth Development (SECCYD) that highlight the fragility of effects reported in the literature on the molecular-genetic correlates of infant attachment. Specifically, this paper updates and provides three extensions to results reported in Luijk et al. (2011), which recently failed to replicate evidence from smaller-sample studies that a set of dopaminergic, serotonergic, and oxytonergic markers are significantly associated with infant attachment security or disorganization. First, we report here that the average effect of “usual suspect” polymorphisms on infant attachment security and disorganization in the SECCYD is approximately zero. Second, because Luijk et al. (2011) reported data based exclusively on the White infants in the SECCYD, this paper reveals that the average effect of polymorphisms featured in this literature is also of trivial magnitude in the non-White sub-sample (cf. Chen, Barth, Johnson, Gotlib, & Johnson, 2011). Third, this paper attempts, but fails, to replicate a recent finding by Raby et al. (2012) suggesting that, although molecular-genetic polymorphisms might not be implicated in security versus insecurity, the serotonin transporter gene contributes to variation in emotional distress during the Strange Situation Procedure. Implications for future research on the genetics of developmental phenotypes in general and attachment in particular are discussed, with a focus on statistical power and model-based theory testing.     

Splenic macrophages in preterm infants: a necropsy study.

AIMS: To study the frequency and nature of histiocytes in the splenic red pulp of infants who died following complicated immaturity/prematurity. METHODS: Twenty four preterm/immature infants were investigated. Frozen sections of formalin fixed splenic tissue were stained with Oil Red O. Paraffin wax sections from the same tissue were conventionally stained with haematoxylin and eosin. Immunohistochemistry was carried out for a number of macrophage markers. The administration of Intralipid was compared with the presence and extent of tissue macrophages. RESULTS: The spleens of 10 infants showed varying degrees of Oil Red O positivity ranging from mild to strong. In all these cases varying numbers of macrophages were confirmed in the splenic parenchyma in ordinary sections. The immunomarkers indicated that the histiocytes belonged to the macrophage phagocytic system. Of the 10 cases with splenic macrophages all had received Intralipid. Of those not receiving Intralipid none showed splenic macrophages. Seven had received Intralipid but did not have splenic macrophages; they had either only received small amounts of Intralipid or Intralipid was discontinued before death. CONCLUSIONS: Splenic macrophages are common at necropsy in immature/preterm infants. The macrophages are most lucidly demonstrated using Oil Red O staining in frozen sections. There is a strong association between the presence of splenic macrophages and Intralipid administration.     

Physiological correlates of learning by performance feedback in children: a study of EEG event-related potentials and evoked heart rate

In this study we measured event-related potentials (ERPs) and evoked heart rate (EHR) to investigate performance monitoring in 10–12-year-old children. The children received feedback on their performance while conducting a probabilistic learning task. Error-related ERP components time-locked to the response increased in amplitude when the children had learned the task, whereas the feedback-locked components decreased. Concerning EHR, there was a general reduction in feedback-related heart rate deceleration when the children had learned. Moreover, a prolonged heart rate deceleration was observed at negative feedback onset in comparison to positive feedback, which shifted in timing when the task progressed. Together, the ERP and EHR-measures suggest a shift from external to internal monitoring when the children are learning by performance feedback. The data suggest that error- and feedback-related EHR deceleration is a reflection of the same error monitoring system that is responsible for the emergence of the error-related negativity (ERN).     

Physiological correlates of learning by performance feedback in children: a study of EEG event-related potentials and evoked heart rate

In this study we measured event-related potentials (ERPs) and evoked heart rate (EHR) to investigate performance monitoring in 10-12-year-old children. The children received feedback on their performance while conducting a probabilistic learning task. Error-related ERP components time-locked to the response increased in amplitude when the children had learned the task, whereas the feedback-locked components decreased. Concerning EHR, there was a general reduction in feedback-related heart rate deceleration when the children had learned. Moreover, a prolonged heart rate deceleration was observed at negative feedback onset in comparison to positive feedback, which shifted in timing when the task progressed. Together, the ERP and EHR-measures suggest a shift from external to internal monitoring when the children are learning by performance feedback. The data suggest that error- and feedback-related EHR deceleration is a reflection of the same error monitoring system that is responsible for the emergence of the error-related negativity (ERN).     

Physiological correlates of musth: lipid metabolites and chemical composition of exudates.

Physiological changes related to lipid metabolism, behavior, and chemicals released in body exudates were studied during musth in the Asian elephant, Elephas maximus, as a case study. During musth, changes in serum testosterone and triglyceride concentrations followed similar patterns, with the former increasing sooner than the latter. Deviant behavior increased during changing androgen levels. The observed high concentrations of testosterone were positively and significantly correlated with increased triglycerides. Lipase activity elevated significantly immediately before and after musth. Blood pH increased significantly in alkalinity. Urine and temporal gland secretions released variable amounts of compounds, some of which may be chemical signals. During musth, temporal gland and urinary exudates demonstrated increased acetone and other ketones indicative of lipid metabolic alterations. Large quantities of nonmethane hydrocarbons, especially 2-butanone, were released from the seemingly dry orifice of the temporal gland before the start of overt musth and before maximum blood elevations were observed; isoprene release was similar. However, maximal acetone levels occurred simultaneously in blood, temporal gland secretions, and urine. Metabolically, musth is a series of interwoven, changing stages of increasing and decreasing hormones and lipid-related constituents. Released chemicals can be quantitatively related to these internal physiological events; some observed behaviors appear to result from altered chemical signals.     

Physiological correlates of adaptation to a rotated visual field

1. Perceptual adaptation to a 30 or 45 degrees visual tilt was induced in human subjects by means of prismatic spectacles worn for 5-7 days. Relative contrast thresholds and the amplitudes of the occipital potentials to vertical and oblique gratings were studied.2. During continuous exposure to the tilted visual environment the normal differences between contrast thresholds for vertical and oblique targets decreased or were no longer significant. In all subjects the change from control threshold differences was significant at the 0.005 level.3. During the course of adaptation the difference in amplitude of the potentials evoked by vertical and oblique oscillating gratings also decreased. The changes with respect to control differences were significant at the 0.005 level in each subject.4. Intermittent exposure to tilt in one subject resulted only in minor adaptation of the apparent vertical, and the evoked potential differences did not change from control levels.5. The changes are interpreted as suggesting that plastic changes in the extraretinal mechanism responsive to target orientation occur during adaptation to prismatic tilt.