Altered cortisol reactivity in individuals with asthma likely increases the risk of inflammation in the face of stress. Understanding antecedents of cortisol reactivity enhances knowledge of factors affecting asthma. Forty-eight subjects genetically predisposed for asthma, recruited from a study that assessed them from birth, completed a laboratory stress procedure and self-report measures at ages 17–19 years. Observation and parent reports from age 0 to 2 years were used to create a parent child relationship risk variable and to define criteria for a cumulative risk variable. In repeated measures analysis of 46 adolescents, those who had experienced early parent child relationship problems, specifically insecure attachment, had an attenuated cortisol stress response, even after controlling for concurrent psychological function and recent stressors (F = 4.6, p < .005). Cortisol stress response was not related to asthma status. This study supports a relationship between the parent child relationship during the first 2 years of life and later cortisol response to stress in youth at genetic risk for asthma. © 2012 Wiley Periodicals, Inc. Dev Psychobiol

Experimental animal findings suggest that early stress and glucocorticoid exposure may program the function of the hypothalamic–pituitary–adrenal (HPA) axis in the offspring. The extension of these findings to human development is not yet clear. A prospective longitudinal study was conducted on 125 mothers and their normally developing children. Amniotic fluid was obtained at, on average, 17.2 weeks gestation; infant behavior and cortisol response to a separation–reunion stress was assessed at 17 months. Amniotic fluid cortisol predicted infant cortisol response to separation–reunion stress: infants who were exposed to higher levels of cortisol in utero showed higher pre-stress cortisol values and blunted response to stress exposure. The association was independent of prenatal, obstetric, and socioeconomic factors and child–parent attachment. The findings provide some of the strongest data in humans that HPA axis functioning in the child may be predicted from prenatal cortisol exposure. © 2012 Wiley Periodicals, Inc. Dev Psychobiol

Many vertebrates rely extensively on social information, but the value of information produced by other individuals will vary across contexts and habitats. Social learning may thus be optimized by the use of developmental or current cues to determine its likely value. Here, we show that a developmental cue, early maternal care, correlates with social learning propensities in adult rodents. The maternal behavior of rats Rattus norvegicus with their litters was scored over the first 6 days postpartum. Rat dams show consistent individual differences in the rate they lick and groom (LG) pups, allowing them to be categorized as high, low, or mid-LG mothers. The 100-day old male offspring of high and low-LG mothers were given the opportunity to learn food preferences for novel diets from conspecifics that had previously eaten these diets (“demonstrators”). Offspring of high-LG mothers socially learned food preferences, but offspring of low-LG mothers did not. We administered oxytocin to subjects to address the hypothesis that it would increase the propensity for social learning, but there were no detectable effects. Our data raise the possibility that social learning propensities may be both relatively stable throughout life and part of a suite of traits “adaptively programmed” by early developmental experiences. © 2012 Wiley Periodicals, Inc. Dev Psychobiol

In humans, maternal cues guide newborns to the maternal breast, and transitional cues may be present in maternal–fetal fluids. The aim of the present study was to determine the consistent presence of sensorial cues in three maternal–fetal fluids—amniotic fluid, colostrum, and milk—and test the ability of these cues to produce appetitive responses in newborns. In the analytical study, gas chromatography-mass spectrometry (GC-MS) detected eight fatty acids consistently present in the amniotic fluid, colostrum, and milk from 12 healthy volunteers, but we do not find a mammalian pheromone, identified in another mammalian species (rabbits), in another 30 volunteers. In the behavioral study, we explored the ability of amniotic fluid or its fatty acids to produce appetitive responses in 19 human newborns <24 hr after birth. Exposure to swabs impregnated with amniotic fluid or an artificial fatty acid mixture produced a longer duration of facial reactions that suggested appetitive (sucking) movements compared with respective vehicles (i.e., propylene glycol or centrifuged amniotic fluid with a low fatty acid content verified by GC-MS). We conclude that the fatty acids contained in amniotic fluid may constitute a transitional sensorial cue that guides newborns to the maternal breast. © 2012 Wiley Periodicals, Inc. Dev Psychobiol

Behavioral effects of different prenatal stress (PNS) schedules were examined in prepubertal “depressive/anxious-like” WKY and control Wistar rats. Pregnant dams received 1 hr daily restraint stress on gestational days 14–20 or on 7 randomly scheduled days, or remained undisturbed. Offspring were tested during postnatal days 29–35 in social play, forced swim-test, open field, and novelty tests. PNS induced an increase in anxiety-like behaviors in WKY, particularly in females, while seemingly reducing depressive-like behavior in the swim test. However, very high post-stress corticosterone levels were found, suggesting that the reductions in swim-test immobility reflect an extremely over-responsive HPA axis, rather than normalization in stress reactivity leading to a less depressive-like profile. In Wistar, PNS produced weight loss, hyperactivity and risk taking behavior, especially in males. The results support the importance of the environment during gestation and its interaction with sex and genetics on long-term anxiety and depressive like behaviors. © 2012 Wiley Periodicals, Inc. Dev Psychobiol

The unconditioned stimulus pre-exposure effect (US-PE) refers to the interference paradigm in which acquisition of the conditioned response is retarded due to prior experience with the US. Most studies analyzing the psychological mechanisms underlying this effect have been conducted with adult rats. The most widely accepted hypothesis explains this effect as a contextual blocking effect. Contextual cues associated with the US block the conditioned stimulus (CS)-US association during conditioning. The modulatory role of a context devoid of distinctive olfactory attributes is not observable until approximately PD23 in rats, including modulation of interference paradigms such as latent inhibition or extinction. In this study, we analyzed US-PE in preweanling rats along with the role of the training context in this effect in terms of conditioned taste aversion preparation. Pre-exposure to LiCl before conditioning retarded the acquisition of taste aversion. The US-PE was observed in preweanling rats when, during pre-exposure, subjects were exposed to the conditioning context, and this effect was not attenuated either by the administration of the US in a familiar environment (Experiment 1a), or by the presence of an alternative, more salient context during pre-exposure (Experiment 1b). Additionally, the US-PE was still observed when the route by which the US was administered was changed between the pre-exposure and conditioning phases (Experiment 2a) as well as when the injection cues were removed during conditioning (Experiment 2b). These experiments show a strong US-PE in preweanling rats and fail to support the contextual blocking hypothesis, at least in this stage of ontogeny.

© 2012 Wiley Periodicals, Inc. Dev Psychobiol

Among mammals, odor-based communication between females and infants is decisive for neonatal survival. So far, the nature of odor substrates involved in the localization of the mother and their nipples is unknown in mice. The present study aims: (1) to evaluate the specific attractive value of lactating females to newborn mice, (2) to localize the abdominal region that is most attractive to pups, and (3) to identify odor substrates that support such attraction. Results showed that 5–6-day-old mice roam preferentially over the abdomen of lactating females than the abdomen of non-lactating females. In lactating females, pups are more attracted to abdominal areas comprising nipples. The blend of odor substrates from nipples, as well as separate sources presumed to compose it, viz. milk, maternal saliva and pup saliva, were detectable and equivalently attractive to pups. The equivalent attraction of these different odor substrates may derive either from overlap in chemical constituents, or from associative learning during nursing. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The development of separation response behaviors in infant rhesus macaques across the first 6 months of life was assessed. Seventeen infants underwent a neonatal assessment at 7, 14, 21, and 30 days of age which included a brief period of social isolation. At 3 and 6 months of age these same monkeys and four additional subjects were again subjected to a period of brief social isolation and also exposed to a novel environment with their sedated mother. Results indicate a developmental increase followed by a steady decline in the frequency of separation vocalizations. A modest relationship between early-infancy locomotor profiles and separation responses was also observed at several time points suggesting a possible relationship between these measures. However, stable inter-individual measures of separation distress did not emerge until late in the infantile period. This could suggest that high levels of maternal contact-seeking behavior early in infancy are context specific and not a reliable index of enduring temperament. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The unconditioned stimulus preexposure effect (US-PE) is defined as an attenuation of the conditioned response after preexposure to the US prior to conditioning. Evidence exists that this effect can be weakened or eliminated by the presence of a signal predicting the US during the preexposure phase. This evidence has been found consistently across a variety of procedures in adult rats. The aim of the present study was to evaluate whether, in infant rats, signaling the US (LiCl) during preexposure with a salient cue (almond odor) attenuates the US-PE. During the preexposure phase, preweanling rats received three (Experiment 1) or one (Experiment 2) preexposures to LiCl, preceded by exposure to almond odor. Appropriate control groups were also included in these experiments. After preexposure, two conditioning trials were carried out in which subjects were given LiCl after saccharin consumption. During preexposure, three (Experiment 1a), although not one (Experiment 2a), contingent exposures to almond odor and LiCl resulted in a strong odor aversion. Extinction of the learned taste aversion was facilitated by prior experience with LiCl (Experiments 1b and 2b). This effect was observed regardless of whether or not LiCl was signaled by the almond odor. These results do not coincide with the associative hypotheses proposed to explain the US-PE, nor are they concurrent with alternative explanations based on the learned helplessness phenomenon. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The current study builds on the emerging autism spectrum disorder (ASD) literature that associates autonomic nervous system activity with social function, and examines the link between respiratory sinus arrhythmia (RSA) and both social behavior and cognitive function. The RSA response pattern was assessed in 23 4- to 7-year-old children diagnosed with an ASD. Higher baseline RSA amplitudes were associated with better social behavior (i.e., more conventional gestures, more instances of joint attention) and receptive language abilities. Similar to reports of typically developing children, ASD children with higher RSA amplitude at baseline showed greater RSA and HP reactivity during an attention-demanding task. These results highlight the importance of studying RSA as a marker of positive function in children with ASD. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Episodic memory endows us with the ability to reflect on our past and plan for our future. Most theorists argue that episodic memory emerges during the preschool period and that its emergence might herald the end of childhood amnesia. Here, we show that both 3- and 4-year-old children form episodic memories, but that 3-year-old children fail to retain those memories following a delay (Experiments 1 and 2). In contrast, 4-year-old children retained episodic memories over delays of 24 hr (Experiment 1) and 1 week (Experiment 3). This marked change in the retention of episodic memories between 3 and 4 years of age suggests that it is our ability to retain, rather than to form, an episodic memory that limits our ability to recall episodes from early childhood. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

A major advantage of sheep models in experimental studies of neurodevelopmental disorders (e.g., with prenatal neurotoxicant exposure) is that the equivalent of all three trimesters of human brain development occurs in sheep entirely in utero. However, studies of learning and memory in sheep are limited. The goal of this study was to extend the analysis of spatial learning and memory in adolescent sheep using several traditional T-maze tasks. Both 9- and 14-week-old lambs acquired a delayed nonmatching-to-place task, but the older lambs learned the task significantly faster. In contrast, acquisition of a matching-to-place task was significantly more difficult. Lambs, like rodents, appear to have a predisposition toward learning “win-shift” spatial problems in a T-maze under appetitive motivation. Lambs also rapidly acquired a position habit and showed typical reversal learning curves. These findings support the use of T-maze tasks to assess behavioral outcomes in various sheep models. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Stereotypic behavior in captive animals has been hypothesized to emerge from thwarted natural behavior patterns and is thought to be more common in captive-reared animals. However, data on the early stages of developing stereotypies are currently scarce. We compared the development of stereotypic route-tracing and somersaulting in hand-reared and wild-caught starlings placed in individual cages for the first time. We found that wild-caught birds were less active but showed more escape motivation and more evidence of route-tracing behavior. Furthermore, somersaulting was only observed in wild-caught birds. Development of somersaulting was predicted by subtle differences in behavior during the first few days in cages and developed in individuals with low levels of route-tracing behavior. Our data suggest a role for escape motivation in the development of starling stereotypies and additionally that route-tracing and somersaulting may represent alternative outlets for thwarted escape. In contrast to observations from mammals, our results show that stereotypies are more common in wild-caught starlings. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Early development of visual behavior was examined in hand-reared (HR) and parentally reared (PR) common marmosets (Callithrix jacchus). On the day of birth, most of the marmosets exhibited sensitivity to light and sound: they closed their eyes in response to light and oriented to the sound sources. The behavior of tracking moving visual stimuli was exhibited at around 10 days postnatally in PR marmosets, but the onset of this behavior was delayed to the age of 16 days in HR marmosets. The delay occurred possibly because of the poor input of optical flow under the HR environment. The onset age of head-cocking was about 2 weeks in both groups of marmosets, and the HR marmosets began head-cocking and visual tracking simultaneously. Both groups of marmosets exhibited sensitivity to optical approach at the age of around 30 days: the age to wean and increase independent locomotion. The results suggested that the onset of motion perception preceded detailed shape and depth perception in marmosets, and the developmental sequence in marmosets was similar to those in humans and macaque monkeys. Marmosets appear to be useful animal models to examine environmental effects on early visual development. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The aim of this study was to test the hypothesis that the renin-angiotensin system (RAS) components, as well as the oxidative stress system, would respond to early environmental changes. Thus, we have evaluated the effects of neonatal handling on both brain and kidney RAS and oxidative stress. Pups were divided into two groups: nonhandled and handled. The procedure consisted of handling them for 1 min/day in the first 10 days of life. On days 1, 5, and 10, animals were killed by decapitation. Blood samples were collected and the brain and kidneys were removed. Renin, AT₁, and AT₂ mRNA expression were evaluated through RT-PCR. Angiotensin II (ANG II) serum concentration was also measured. An increased ANG II concentration, brain and kidney AT₂ mRNA expression were demonstrated. The kidney mRNA AT₁ expression was decreased. There was also a kidney lipid peroxidation increase and a brain superoxide dismutase and catalase decrease. In conclusion, handling in the neonatal period induces the activation of the angiotensinergic system, as well as modulates its mRNA receptor expression. The oxidative stress balance system seems not to be involved. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The context preexposure facilitation effect (CPFE) is a variant of contextual fear conditioning in which context learning and context-shock associations occur on separate occasions. The CPFE with an immediate shock emerges between Postnatal Day (PND) 17 and 24 in the rat and depends on hippocampal NMDA-receptor function in PND 24 rats (Schiffino et al. [2011] Neurobiology of Learning and Memory 95(2):190–198). This study investigated this ontogenetic effect further and reports three findings: First, the CPFE is absent on PND 19 but emerges modestly in rats given exposure on PND 21. Second, the absence of the CPFE on PND 17 does not reflect inability to consolidate the context-shock association established on the training day. Lastly, the CPFE on PND 24 requires exposure to the combined features of the context. These results are the first to show that the early development of contextual fear conditioning depends on conjunctive representations and that processes underlying the CPFE begin to emerge around PND 21 in the rat. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The current study examined the moderating effect of children's cardiac vagal suppression on the association between maternal socialization of negative emotions (supportive and nonsupportive responses) and children's emotion regulation behaviors. One hundred and ninety-seven 4-year-olds and their mothers participated. Mothers reported on their reactions to children's negative emotions and children's regulatory behaviors. Observed distraction, an adaptive self-regulatory strategy, and vagal suppression were assessed during a laboratory task designed to elicit frustration. Results indicated that children's vagal suppression moderated the association between mothers' nonsupportive emotion socialization and children's emotion regulation behaviors such that nonsupportive reactions to negative emotions predicted lower observed distraction and lower reported emotion regulation behaviors when children displayed lower levels of vagal suppression. No interaction was found between supportive maternal emotion socialization and vagal suppression for children's emotion regulation behaviors. Results suggest physiological regulation may serve as a buffer against nonsupportive emotion socialization. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The current study examined developmental changes in fear learning and generalization in 40 healthy 8–13 year-olds using an aversive conditioning paradigm adapted from Lau et al. [Lau et al. [2008] Journal of the American Academy of Child and Adolescent Psychiatry 47:94–102]. In this task, the conditioned stimuli (CS+/CS−) are two neutral female faces, and the unconditioned stimulus is a fearful, screaming face. The second phase of the study also included a generalization stimulus (GS): a 50% blend of the CS± faces. The eye-blink startle reflex was utilized to measure defensive responding. Patterns of fear learning and generalization were qualified by child age. Older children demonstrated greater fear learning (i.e., larger startle during CS+ than CS−) than younger children. In addition, older children exhibited the typical pattern of generalization observed in adults, whereas younger children did not. Finally, fear learning also related to contingency awareness; only children who correctly identified the CS+ demonstrated fear-potentiated startle to the CS+. Clinical implications and future directions are discussed. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Adverse early experiences are associated with a range of deleterious health outcomes in humans, including higher risk for affective disorders. Studies using a long-standing model of nonhuman primate model of early adversity have demonstrated that nursery-reared (NR) monkeys exhibit alterations in multiple aspects of biobehavioral development; however, few studies have evaluated the persistence of socioaffective behavioral changes through adulthood. We evaluated the effects of early rearing experience on adult animals' response to a well-validated assessment of anxiety-like behavior, the human intruder paradigm (HIP). We tested 22 rhesus monkeys who were either nursery-reared (NR) or reared with their mothers (mother-reared; MR). NR monkeys were inhibited in their behavior compared to MR monkeys, with reduced locomotion and exploratory behaviors. NR animals showed a marginal increase in freezing. Together these findings demonstrate that the consequences of differential infant rearing experience on socioaffective behavior persist into adulthood, with evidence of greater inhibition in NR monkeys. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Adolescence is characterized as a developmental period of risky decision-making. During this developmental window there is also a marked increase in actual and perceived stress. Acute stress increases risky decision-making in adults, but no research has examined this phenomenon in adolescents. In this study, an ecologically relevant approach was used to document daily self-reports of stress in adolescents and an emerging adult comparison group. Participants visited the laboratory twice: once each when they endorsed a high and low level of stress, where they performed a risky decision-making task and a response inhibition task. In both groups, participants showed greater risky decision-making under high (vs. low) stress conditions but no stress-related effects on response inhibition. The dissociation between decision-making and response inhibition under stress suggests that, across development, individuals show greater vulnerability to contextual influence in decision-making domains. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Upon awakening from sleep, combined processes of deactivation of the hippocampus and activation of suprachiasmatic nucleus result in a marked increase in cortisol release from structures within the hypothalamic–pituitary–adrenal axis. This phenomenon, termed the cortisol awakening response (CAR), has been studied extensively in adults. In the current study, we examine this phenomenon for the first time in infancy. Saliva samples were collected by 32 mothers from themselves and their infants (13 males; 7.8–17.4 months of age) at the infant's AM waking (and 30 min later), and upon waking from the infant's first nap (and 30 min later). In contrast to what has been observed with the CAR in adults, cortisol levels declined from AM waking to 30 min post-waking. Moreover, cortisol levels did not significantly rise or fall following naps. Consistent with prior research, both group-level and dyadic-level analyses showed that cortisol levels for mother–infant dyads were associated. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The current study investigated the effects of neonatal infection with Chlamydia muridarum bacteria on glucocorticoid (GR) and mineralocorticoid (MR) receptors in the adult mouse hippocampus. In male adults infected at birth, circulating corticosterone was significantly increased when compared to same sex controls; while neonatal infection resulted in female adults with significantly increased GR mRNA compared to same sex controls. When comparing males and females after neonatal infection, males had significantly less GR protein than females. Interestingly, after control treatment, males had significantly more GR mRNA, MR mRNA, and GR protein with significantly lower corticosterone than females. Neonatal respiratory infection significantly impacts adult hippocampal GR and MR, and circulating corticosterone in a sex-specific manner potentially altering stress responsivity. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Individual differences in observed and maternal-rated fear behaviors and frontal electroencephalogram (EEG) asymmetry were examined in normally developing 10-month-old infants. EEG was recorded during resting baseline, as well as during stranger approach, mask presentation, and toy spider presentation. Mothers completed the Infant Behavior Questionnaire. For mask presentation, baseline and task right frontal EEG asymmetry as well as maternal ratings predicted fear behavior during the mask task. For stranger approach, task-related right frontal EEG asymmetry predicted fear behavior during stranger approach after controlling for baseline asymmetry. There was a trend for task-related right frontal EEG asymmetry to predict fear during presentation of a toy spider after controlling for baseline asymmetry. Maternal report of temperament only added unique variance to the prediction of one fear task after controlling for baseline and task EEG. Assessing fear in multiple situations revealed context-specific individual differences in infant fear. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Compromised respiratory sinus arrhythmia (RSA, i.e., low cardiac vagal control) frequently characterizes clinically depressed adults and also has been detected in infants of depressed mothers; however, its existence has not been established in older at-risk offspring. We investigated developmental patterns of RSA in a sample of 163 5- to 14-year-old children, who were either at high risk for depression (due to having a parent with a childhood-onset mood disorder) or low-risk for depression. We hypothesized that high-risk children have lower resting RSA than do low-risk children, which could reflect atypical developmental trajectories. Children's RSA was assessed during resting baseline periods on multiple occasions, typically 1-year apart. Linear growth modeling indicated a group by age interaction. Low-risk children (but not the high-risk children) exhibited a significantly increasing trajectory in resting RSA with age. Mood disorders in offspring did not account for the Group X Age interaction effect. Our study provides new evidence that children at high risk for depression have an atypical developmental trajectory of RSA across late childhood. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

This study was conducted to compare how newborns of depressed mothers and newborns of nondepressed mothers gather tactile information about texture. Spontaneous manual activity on objects with a smooth or rough texture was recorded in 20 newborns born of mothers with a high risk of depression or a low risk of depression. An important result of the present study is that texture-based modulation of hand-pressing frequency was observed in both neonates born of depressed mothers and neonates born of nondepressed mothers. Moreover, hand-pressing frequency did not depend on the pressure exerted on the object, since all neonates displayed comparable pressure on the held object. Lastly, the results revealed that newborns of depressed mothers held the rough object twice as long as newborns of nondepressed mothers. These results are analyzed in reference to deregulated biochemical functions in neonates born of mothers with a high risk of depression. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Kinematic studies of reaching in human infants using two-dimensional (2-D) and three-dimensional (3-D) recordings have complemented behavioral studies of infant handedness by providing additional evidence of early right asymmetries. Right hand reaches have been reported to be straighter and smoother than left hand reaches during the first year. Although reaching has been a popular measure of handedness in primates, there has been no systematic comparison of left and right hand reach kinematics. We investigated reaching in infant rhesus monkeys using the 2-D motion analysis software MaxTRAQ Lite+ (Innovision Systems). Linear mixed-effects models revealed that left hand reaches were smoother, but not straighter, than right hand reaches. An early left bias matches previous findings of a left hand preference for reaching in adult rhesus monkeys. Additional work using this kind of kinematic approach will extend our understanding of primate handedness beyond traditional studies measuring only frequency or bouts of hand use. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

This analysis examined the relative contributions of sex, age, body mass index (BMI), and puberty (Tanner) stage on salivary melatonin amplitude. Sixty-nine children and adolescents (30 females; 9.6–17.8 years) were examined for Tanner stage. Serial salivary melatonin samples were collected in controlled conditions, from which these melatonin amplitude measures were derived: area under the curve (AUC) and maximum value (MAX). AUC declined with advancing Tanner stage. This melatonin decline was similar between boys and girls, but girls secreted more melatonin compared to boys. Tanner stage and sex explained AUC variability, but age and BMI did not; similar results emerged for MAX. These results indicate that puberty stage may either mediate the decline of melatonin, or the decrease in melatonin amplitude may be an indicator of pubertal progression. These findings also indicate that the melatonin decline during puberty is not entirely accounted for by body mass or by age. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

This longitudinal prospective study examined the relation between maternal anxiety during pregnancy and specific aspects of children's cognitive functioning at age five. Antenatal maternal state-anxiety was measured around the 16th week of pregnancy. Children's neurocognitive functioning was examined using a simple reaction time (RT) task, and a choice RT task. Multiple regression analyses in the total sample (N = 922) showed that antenatal anxiety was positively related to children's intra-individual variability in RT in the simple task. In a subsample (n = 100) of women with state-anxiety scores above the 90th percentile, antenatal anxiety was positively associated with mean RT and intra-individual variability in RT in the incompatible trials of the choice RT task. In addition, in this subsample of highly anxious mothers we found a significant positive association in boys but not in girls, between prenatal maternal anxiety and intra-individual variability in RT in the simple task. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

This study aimed to (1) identify a stable, trait-like component to cortisol and its circadian rhythm, and (2) investigate individual differences in developmental trajectories of HPA-axis maturation. Multiple salivary cortisol samples were collected longitudinally across four assessments from age 9 (3rd grade) through age 15 (9th grade) in a community sample of children (N = 357). Sophisticated statistical models examined cortisol levels and its rhythm over time; effects of age, puberty and gender were primarily considered. In addition to situation-specific and stable short-term or epoch-specific cortisol components, there is a stable, trait-like component of cortisol levels and circadian rhythm across multiple years covering the transition from childhood into adolescence. Youth had higher cortisol and flatter circadian rhythms as they got older and more physically developed. Girls had higher cortisol, stronger circadian rhythms, and greater developmental influences across adolescence. Distinguishing a stable, trait-like component of cortisol level and its circadian rhythm provides the empirical foundation for investigating putative mechanisms underlying individual differences in HPA functioning. The findings also provide important descriptive information about maturational processes influencing HPA-axis development. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Early attachment disruption is thought to promote later onset of depressive illness through a process involving sensitization. Maternal separation in guinea pig pups produces depressive-like behavior and core body temperature fluctuations that appear to be mediated by proinflammatory activity. In pups near the age of weaning (∼20 days of age), these responses are increased during repeated separations occurring over several days. Here, enhanced depressive-like behavior and core body temperature responses were observed during repeated separations in guinea pigs from ∼10 to 30 days of age. The sensitization lasted for more than a week, with the greatest temperature response occurring during the final separation. These results demonstrate persisting sensitization of behavioral and thermogenic responses to maternal separation over the age range in which these responses are known to occur. The findings are consistent with the hypothesis that proinflammatory activity contributes to the sensitization response and provide further suggestion that the impact of early attachment disruption on susceptibility to depression may involve proinflammatory processes. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The extent to which characteristic adolescent behaviors are associated with pubertal changes or driven by more general, puberty-independent developmental alterations is largely unknown. Using physiological and hormonal markers of puberty, this experiment characterized pubertal timing across adolescence and examined the relationships among these variables and novelty-directed behaviors. Males and females were tested for response to novelty at P28, P32, P36, P40, P44, P48, and P75, and examined for balano-preputial skinfold separation and sperm presence (males) or vaginal opening (females), followed by blood collection for hormonal assessments. Despite earlier pubertal maturation in females, with maturation generally completed by P36 in females and P44 in males, novelty-directed behavior peaked at P32 and P36 in both sexes, and was unrelated to pubertal measures. These data support the suggestion that the ontogenetic peak in this behavior during adolescence is not notably puberty dependent. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The cortisol awakening response (CAR) is presumed critically important for healthy adaptation. The current literature, however, is hampered by systematic measurement difficulties relative to awakening, especially with young children. While reports suggest the CAR is smaller in children than adults, well-controlled research in early childhood is scarce. We examined whether robust CARs exist in 2- to 4-year-old children and if sleep restriction, wake timing, and napping influence the CAR (n = 7). During a 25-day in-home protocol, researchers collected four salivary cortisol samples (0, 15, 30, 45 min post-wake) following five polysomnographic sleep recordings on nonconsecutive days after 4 hr (morning nap), 7 hr (afternoon nap), 10 hr (evening nap), 13 hr (baseline night), and 16 hr (sleep restriction night) of wakefulness (20 samples/child). The CAR was robust after nighttime sleep, diminished after sleep restriction, and smaller but distinct after morning and afternoon (not evening) naps. Cortisol remained elevated 45 min after morning and afternoon naps. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Eyeblink classical conditioning in pre-weanling rabbits was examined in the present study. Using a custom lightweight headpiece and restrainer, New Zealand white littermates were trained once daily in 400 ms delay eyeblink classical conditioning from postnatal days (PD) 17–21 or PD 24–28. These ages were chosen because eyeblink conditioning emerges gradually over PD 17–24 in rats [Stanton et al., (1992) Behavioral Neuroscience, 106(4):657–665], another altricial species with neurodevelopmental features similar to those of rabbits. Consistent with well-established findings in rats, rabbits trained from PD 24–28 showed greater conditioning relative to littermates trained from PD 17–21. Both age groups displayed poor retention of eyeblink conditioning at retraining 1 month after acquisition. These findings are the first to demonstrate eyeblink conditioning in the developing rabbit. With further characterization of optimal conditioning parameters, this preparation may have applications to neurodevelopmental disease models as well as research exploring the ontogeny of memory. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

This study investigated adrenocortical activity in response to different challenging and positive affect emotional contexts in child–mother dyads, as function of attachment security (children's secure base behaviors and mothers' attachment representations). Fifty-one children ranging in age from 18 to 26 months and their mothers participated in this study. Secure children showed significant increases in their cortisol levels after fear episodes and significant decreases, after positive affect ones. No significant changes were found for frustration/anger episodes. Insecure children did not show significant differences in cortisol levels in any of the episodes, which suggests that insecure attachment may be related to hypothalamic–pituitary–adrenal axis suppression in response to challenging and positive contexts. Mothers of insecure children showed significantly higher cortisol concentrations in pre- and post-session samples, than mothers of secure children. Mothers' personal attachment representations influenced their own cortisol responses, as well as their children's (in a marginal significant way). © 2011 Wiley Periodicals, Inc. Dev Psychobiol

Motor overflow is extraneous movement in a limb not involved in a motor action. Typically, overflow is observed in people with neurological impairments and in healthy children and adults during strenuous and attention-demanding tasks. In the current study, we found that young infants produce vast amounts of motor overflow, corroborating claims of symmetry being the default state of the motor system. While manipulating an object with one hand, all 27 of the typically developing 4.5- to 7.5-month-old infants who we observed displayed overflow movements of the free hand (on 4/5 of unimanual actions). Mirror-image movements of the hands occurred on 1/8 of unimanual actions, and the hands and legs moved in synchrony on 1/3 of unimanual acts. Motor overflow was less frequent when infants were in a sitting posture and when infants watched their acting hand, suggesting that upright posture and visual examination may help to alleviate overflow and break obligatory symmetry in healthy infants. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The majority of children who are born very preterm escape major impairment, yet more subtle cognitive and attention problems are very common in this population. Previous research has linked infant focused attention during exploratory play to later cognition in children born full-term and preterm. Infant focused attention can be indexed by sustained decreases in heart rate (HR). However there are no preterm studies that have jointly examined infant behavioral attention and concurrent HR response during exploratory play in relation to developing cognition. We recruited preterm infants free from neonatal conditions associated with major adverse outcomes, and further excluded infants with developmental delay (Bayley Mental Development Index [MDI < 70]) at 8 months corrected age (CA). During infant exploratory play at 8 months CA, focused attention and concurrent HR response were compared in 83 preterm infants (born 23–32 weeks gestational age [GA]) who escaped major impairment to 46 full-term infants. Focused attention and HR response were then examined in relation to Bayley MDI, after adjusting for neonatal risk. MDI did not differ by group, yet full-term infants displayed higher global focused attention ratings. Among the extremely preterm infants born <29 weeks, fewer days on mechanical ventilation, mean longest focus, and greater HR deceleration during focused attention episodes, accounted for 49% of adjusted variance in predicting concurrent MDI. There were no significant associations for later-born gestational age (29–32 weeks) or full-term infants. Among extremely preterm infants who escape major impairment, our findings suggest unique relationships between focused attention, HR deceleration, and developing cognition. © 2011 Wiley Periodicals, Inc. Dev Psychobiol

The sensory processing of odorants is a dynamic process that requires plasticity at multiple levels. In the olfactory bulb (OB), inhibitory interneurons undergo lifelong replacement through a process known as adult neurogenesis. These newly born cells are incorporated in a learning-dependent fashion, a process which has led some to suggest this as a primary mechanism through which the OB retains a high degree of plasticity throughout life. A continued focus of researchers in this field has been to understand the molecular mechanisms controlling adult subventricular zone (SVZ) neurogenesis and the innate functional role of these cells. Brain-derived neurotrophic factor (BDNF) has been identified as a strong candidate molecule regulating adult OB neurogenesis. We review what is known regarding the functional role of newly born cells, highlight the role of BDNF in this process, and describe preliminary findings from our lab implicating BDNF in the process of selecting of newly born cells for survival. © 2011 Wiley Periodicals, Inc. Dev Psychobiol.

There are striking similarities between the visual defect of amblyopia and the motor deficit of the extremities produced by such types of damage to the central nervous system (CNS) as stroke and traumatic brain injury, both after and before maturity. Part of the motor deficit of the extremities following CNS injury can be attributed to a learning phenomenon termed “learned nonuse” or if present from birth, “developmental disregard.” The same mechanism is hypothesized to be involved in the development of amblyopia. Treatments that are efficacious in the remediation of these defects, Constraint-Induced Movement therapy and amblyopia training, also share a number of strong similarities. In addition, plastic brain changes are produced by CI therapy and are hypothesized to occur during amblyopia training. © 2010 Wiley Periodicals, Inc. Dev Psychobiol

Mirror neurons discharge during the execution of ecological goal-directed manual and oral actions, as well as during the observation of the same actions done by other individuals. These neurons were first identified in the ventral premotor cortex (PMv; area F5) and later on in the inferior parietal lobule (areas PF and PFG) of monkey brain, constituting a “mirror neuron” system. Several pieces of experimental data suggest that a mirror neuron system devoted to hand, mouth, and foot actions might also be present in humans. In the present paper, we review the experimental evidence on the role of the mirror neuron system in action understanding and imitation, both in hand motor function and speech. Based on the features of the mirror neuron system and its role in action understanding and imitation, we discuss the use of action observation and imitation as an approach for systematic training in the rehabilitation of patients with motor impairment of the upper limb and aphasia following stroke. We present the results of some preliminary studies to test this concept, and a discussion of network models as a measure of neurobiological change. © 2010 Wiley Periodicals, Inc. Dev Psychobiol

The fundamental concept in the emerging field of rehabilitation and brain plasticity is that although there is much constancy in brain function and organization across our lifetime, there is remarkable variability as well. This variability reflects the brain's capacity to alter its structure and function in reaction to environmental diversity as well as to perturbations including injury throughout the lifespan. Although the term brain plasticity is now widely used, it is not easily defined and is used to refer to changes at many levels in the nervous system ranging from molecular events, such as changes in gene expression, to behavior (e.g., Shaw & McEachern (Eds.) [2001]. Toward a Theory of Neuroplasticity. Philadelphia, USA: Psychology Press). The focus of our work has been to correlate changes in behavior, neuronal morphology, and the organization of motor maps after cortical injury throughout the lifespan. In this article, we review evidence we have collected from a rat model of normal development and the effects of brain injury, and comment on the general principals that may apply to human stroke and amblyopia. © 2010 Wiley Periodicals, Inc. Dev Psychobiol

The human brain possesses a remarkable ability to adapt in response to changing anatomical (e.g., aging) or environmental modifications. This form of neuroplasticity is important at all stages of life but is critical in neurological disorders such as amblyopia and stroke. This review focuses upon our new understanding of possible mechanisms underlying functional deficits evidenced after adult-onset stroke. We review the functional interactions between different brain regions that may contribute to motor disability after stroke and, based on this information, possible interventional approaches to motor stroke disability. New information now points to the involvement of non-primary motor areas and their interaction with the primary motor cortex as areas of interest. The emergence of this new information is likely to impact new efforts to develop more effective neurorehabilitative interventions using transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) that may be relevant to other neurological disorders such as amblyopia. © 2010 Wiley Periodicals, Inc. Dev Psychobiol.

Modern theories of brain function emphasize the importance of distributed functional networks and synchronized activity within and between networks in mediating cognitive functions. This view highlights the importance of considering brain-behavior relationships after focsal lesions not only as the result of local structural damage but also as a more widespread alteration of the physiological state of networks connected to the lesion. Recent findings demonstrate coherent activity in large-scale brain networks not only during task performance, but also, surprisingly, at rest in the absence of stimuli, tasks, or overt responses. Moreover, breakdown of coherent activity at rest, even in regions that are structurally intact, correlates with behavioral deficits and with their recovery after injury. This network perspective is fundamental to understand not only healthy brain function, but also the pathophysiology of brain injuries, mechanisms of functional recovery, and the basis for novel interventions for therapy. © 2010 Wiley Periodicals, Inc. Dev Psychobiol

Noninvasive brain stimulation is a technique for inducing changes in the excitability of discrete neural populations in the human brain. A current model of the underlying pathological processes contributing to the loss of motor function after stroke has motivated a number of research groups to investigate the potential therapeutic application of brain stimulation to stroke rehabilitation. The loss of motor function is modeled as resulting from a combination of reduced excitability in the lesioned motor cortex and an increased inhibitory drive from the nonlesioned hemisphere over the lesioned hemisphere. This combination of impaired neural function and pathological suppression resonates with current views on the cause of the visual impairment in amblyopia. Here, we discuss how the rationale for using noninvasive brain stimulation in stroke rehabilitation can be applied to amblyopia, review a proof-of-principle study demonstrating that brain stimulation can temporarily improve amblyopic eye function, and propose future research avenues. © 2010 Wiley Periodicals, Inc. Dev Psychobiol

Salivary cortisol has been useful for evaluating children's physiological responses to stress and for identifying factors that predict their magnitude and duration. However, results have been somewhat equivocal across studies, and this has motivated researchers to identify sources of variance and error. Here, we examined the prevalence of preschoolers' noncompliance during saliva collection and aimed to learn about noncompliant children in terms of their hypothalamus–pituitary–adrenal function, behavior in other situations, and symptoms of behavioral problems. Results were based on measures of cortisol, children's behavior during saliva collection and a mother–child teaching interaction, and ratings of problem behavior by teachers and parents. Results show that 12% (21/174) of the sample was noncompliant on at least one of the collection trials. Children, who were noncompliant but did not outright refuse saliva collection, had higher cortisol than did compliant children. Children who were noncompliant during saliva collection were likely to be noncompliant during the teaching episode, and they were perceived as having more internalizing symptoms than compliant children. These results suggest that children's noncompliance during saliva collection can be a source of nonrandom missing data or extreme cortisol values, which should be considered in future studies. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:113-123, 2012.

When adults view very realistic humanoid robots or computer avatars they often exhibit an aversion to them. This phenomenon, known as the “uncanny valley,” is assumed to be evolutionary in origin, perhaps tapping into modules for disgust or attractiveness that detect violations of our normal expectations regarding social signals. Here, we test an alternative hypothesis that the uncanny valley is developmental in origin and, thus, that specific early experience with real human faces leads to its eventual emergence. To test this idea, we measured visual preferences in response to all possible pairs of a human face, realistic avatar face, and an unrealistic avatar face in groups of 6-, 8-, 10-, and 12-month-old infants. Consistent with the developmental hypothesis, we found that the uncanny valley effect emerges at 12 months of age suggesting that perceptual experience with real human faces is critical to its emergence. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:124-132, 2012.

Prenatal aluminum exposure may affect the development of the embryo and alter the capacity for learning and memory in adults. The chick embryo is a good experimental model to study the effect of prenatal toxin exposure on cognitive defects in offspring, because it eliminates maternal confounding variables. In the present study, we applied a one-trial passive avoidance-learning task in day-old chicks to examine the effects of prenatal aluminum chloride injections (2, 20, and 200 mM in 200 µl per egg, daily over a period of 4 successive days) on memory consolidation. The data suggest that chicks injected with aluminum chloride (20 mM) daily from E12 to E15 had significantly impaired short-term memory, intermediate-term memory, and long-term memory (LTM) after training (p < .05) but chicks injected with aluminum chloride (2 mM) had impaired LTM only. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:133-138, 2012.

The current study examined behavioral measures and response-locked event-related brain potentials (ERPs) derived from a Go/No-Go task in a large (N = 328) sample of 5- to 7-year-olds in order to better understand the early development of response monitoring and the impact of child age and sex. In particular, the error-related negativity (ERN, defined on both error trials alone and the difference between error and correct trials, or ΔERN), correct response negativity (CRN), and error positivity (P_e) were examined. Overall, the ERN, CRN, and the P_e were spatially and temporally similar to those measured in adults and older children. Even within our narrow age range, older children were faster and more accurate; a more negative ΔERN and a more positive P_e were associated with: increasing age, increased accuracy, and faster reaction times on errors, suggesting these enhanced components reflected more efficient response monitoring of errors over development. Girls were slower and more accurate than boys, although both genders exhibited comparable ERPs. Younger children and girls were characterized by increased posterror slowing, although they did not demonstrate improved posterror accuracy. Posterror slowing was also related to a larger P_e and reduced posterror accuracy. Collectively, these data suggest that posterror slowing may be unrelated to cognitive control and may, like the P_e, reflect an orienting response to errors. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:139-150, 2012.

Adult rats sweep their large facial whiskers (macrovibrissae) back and forth in a rhythmic pattern known as “whisking”. Here we examine how these whisker movements develop in relation to other aspects of exploratory behavior, particularly locomotion. We analyzed 963 high-speed video recordings of neonatal rats, from P1 (Post-natal day 1) to P21, and measured the emergence of whisker control and of head, body, and limb movements. Prior to P11, whisker movements were largely limited to unilateral retractions accompanying head turns. Between P11 and P13 bilateral whisking emerged alongside increased forward locomotion and improved control of the head. Contact-induced modulations of whisking symmetry, synchrony, and whisker spread emerge shortly thereafter but continue to develop until at least P18, coinciding with the emergence of adult-like locomotion patterns such as rearing. Overall, whisking develops alongside increasing locomotor competence indicating that active vibrissal sensing plays an important role in the exploratory behavior of the developing animal. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:151-168, 2012.

To discover whether the accumulation of life's experiences, adverse and enriching, inform, and serve the following generation by inheritance we examine whether stress to a weanling female will influence her future offspring, whether prereproductive enrichment to the dam, or postweaning enrichment to the offspring, can reverse the transgenerational effects of stress, and whether, like adversity, enrichment might have transgenerational effects. Female rats were exposed to stressors when they were 27–29 days old. Half of these females and their controls were then raised in an enriched environment from weaning until mating at 60 days to examine whether preproduction enrichment reverses the effects of preproduction stress on offspring. Half of the offspring of each group were raised in an enriched environment after weaning, to see whether it reverses the effects of preproduction stress and buttresses prereproductive enrichment. Behavior was examined in 625 adult offspring in 16 groups covering all permutations of the experimental variables (preproduction weanling stress (PS), preproduction enrichment (PE), offspring enrichment (OE), sex). Exploration, avoidance learning, startle, and social interaction were tested. Results reveal that very early prereproductive experience in females, adverse or enriching, will transgenerationally influence their future offspring, depending on the behavior tested and sex. Our finding that enrichment, whether to the parent or offspring generation, can ameliorate the transgenerational impact of adversity, has novel implications for the malleability of transgenerational inheritance, and its individual, social, and therapeutic impact. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:169-186, 2012.

This longitudinal study of 27 infants examined the development of pulling-to-stand (PTS). In general, infants began PTS using a two-leg strategy and transitioned to a half-kneel strategy. As a group, infants showed no preference for either strategy at the onset of PTS, switching between strategies until half-kneeling became the dominant pattern about 1 month after the onset of PTS. Examination of individual developmental trajectories revealed variability in age at PTS onset, time between PTS onset and half-kneel strategy onset, duration of the two-leg strategy as the dominant pattern, time until the half-kneel strategy became the dominant pattern, shape of the transition between strategies (gradual vs. abrupt), and timing of PTS relative to onset of other motor milestones. We discuss variation in developmental trajectory in terms of adaptive behavior during the acquisition of new skills and as a process shaped by infants' unique experiences prior to and during the acquisition period. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:187-198, 2012.

Siblings share similar genetics and environments, however, their behavior can be quite different. To determine if within-litter variance in neonatal–maternal interactions predict adult sibling behavioral variance, we observed mother–pup interactions during postnatal days 1–8 in four Sprague–Dawley rat litters and measured adult offspring behavioral responses to social and physical novelty. Our results indicate that pup and maternal behavior varied by at least twofold within each litter, and that specific pup behaviors within each litter (perioral contact) were associated with increased maternal licking. Furthermore, siblings that received more licks and made more perioral contact during postnatal days 1–8 had longer latencies to approach novel objects in adulthood than siblings that received less licking and made less perioral contact. This within-litter variance in postnatal mother and pup behavior and offspring adult behavior indicates that early social dynamics within families are an important area to examine to understand the development of sibling variance. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:199-206, 2012.

Many transformations that occur in adolescence are related to emotion and emotion regulation, yet very little is known about the autonomic underpinnings of these changes. The aim of the study was to document age-related differences in autonomic responses to social stress and relations to emotion regulation. Ninety-nine female adolescents engaged in a paced breathing and a spontaneous speech task while electrocardiography measurements were taken. Spectral decomposition of the heart period data was used to create measures of sympathetic and parasympathetic activity. Results revealed a positive correlation between age and sympathetic activity and a negative correlation between age and parasympathetic activity. These findings contribute to a better understanding of the age-related norms of cardiac variability across adolescence. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:207-214, 2012.

One hundred six infants participated in a longitudinal study of cognition–emotion integration exploring the effects of attentional control on regulation of negative affect across infancy. At both 5 and 10 months, attentional control was measured behaviorally (looking time to neutral stimulus), physiologically (cardiac reactivity), and with temperament-based parental ratings of orienting/regulation. Looking and cardiac measures were examined both before and after a mild stressor. At 5 months, post-distress negative affect was related only to distress-related increases in heart rate. At 10 months, however, behavioral, cardiac, and parent-report aspects of attentional control explained unique variance in post-distress negative affect. Attentional control measures at 5 months did not predict negative affect at 10 months. This pattern of results is discussed with respect to the development of frontally mediated regulatory mechanisms from infancy into early childhood. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:215-221, 2012.