Developmental Psychobiology via MedWorm.com

Sensitivity to ethanol and other hedonic stimuli in an animal model of adolescence: Implications for prevention science?

Developmental Psychobiology — Wed, 10 Mar 2010 00:00:00 +0100

Age-related patterns of sensitivity to appetitive and aversive stimuli seemingly have deep evolutionary roots, with marked developmental transformations seen during adolescence in a number of relatively ancient brain systems critical for motivating and directing reward-related behaviors. Using a simple animal model of adolescence in the rat, adolescents have been shown to be more sensitive than their adult counterparts to positive rewarding effects of alcohol, other drugs, and certain natural stimuli, while being less sensitive to the aversive properties of such stimuli. Adolescent-typical alcohol sensitivities may be exacerbated further by a history of prior stress or alcohol exposure as well as by genetic vulnerabilities, permitting relatively high levels of adolescent alcohol use and pe...

The storm and stress of adolescence: Insights from human imaging and mouse genetics

Developmental Psychobiology — Wed, 10 Mar 2010 00:00:00 +0100

The characterization of adolescence as a time of "storm and stress" remains an open debate. Intense and frequent negative affect during this period has been hypothesized to explain the increased rates of affective disorders, suicide, and accidental death during this time of life. Yet some teens emerge from adolescence with minimal turmoil. We provide a neurobiological model of adolescence that proposes an imbalance in the development of subcortical limbic (e.g., amygdala) relative to prefrontal cortical regions as a potential mechanism for heightened emotionality during this period. Empirical support for this model is provided from recent behavioral and human imaging studies on the development of emotion regulation. We then provide examples of environmental factors that may exacerbate imba...

Sustained parenting and college drinking in first-year students

Developmental Psychobiology — Tue, 09 Mar 2010 00:00:00 +0100

Research indicates that for many students excessive drinking in college is a continuation of high school drinking tendencies. However, there have been limited theory-driven, systematic interventions targeting students so as to prevent alcohol misuse in their transition to college. Almost all current prevention approaches tend to be focused on younger populations and college-drinking interventions are typically delivered to students when they are already on campus. These analyses draw from a novel program of research involving parents of college freshmen based on the work of Turrisi et al. [Turrisi et al. [2001] Psychology of Addictive Behaviors, 15(4), 366-372; Turrisi, et al. [2009] Journal of Applied Social Psychology, 7, 315-326] and focuses on examining: (1) the relationship between pa...

A dual systems model of adolescent risk-taking

Developmental Psychobiology — Mon, 08 Mar 2010 00:00:00 +0100

It has been hypothesized that reward-seeking and impulsivity develop along different timetables and have different neural underpinnings, and that the difference in their timetables helps account for heightened risk-taking during adolescence. In order to test these propositions, age differences in reward-seeking and impulsivity were examined in a socioeconomically and ethnically diverse sample of 935 individuals between the ages of 10 and 30, using self-report and behavioral measures of each construct. Consistent with predictions, age differences in reward-seeking follow a curvilinear pattern, increasing between preadolescence and mid-adolescence, and declining thereafter. In contrast, age differences in impulsivity follow a linear pattern, with impulsivity declining steadily from age 10 on...

Psychobiological models of adolescent risk: Implications for prevention and intervention

Developmental Psychobiology — Mon, 08 Mar 2010 00:00:00 +0100

The papers in this special section address the phenomena of observed increases in risky behavior during the adolescent period of development. Authors provide well-documented evidence that adolescents are at greater risk for a range of psychological and behavioral problems during this period than at any other time in development. The papers share a developmental and psychobiological perspective on this period, noting that biological, social, and contextual factors interact to produce heightened risk for problematic behavior during this period. This perspective suggests several points of entry for intervention and prevention efforts aimed at reducing both mental and behavioral health problems. Gaps in current research efforts are noted, as is the need for more research focusing on mechanisms...

On a multistable dynamic model of behavioral and perceptual infant development

Developmental Psychobiology — Tue, 02 Mar 2010 00:00:00 +0100

In this theoretical work, we treat behavioral and perceptual issues on an equal footing and examine the emergence of mutually exclusive behavioral patterns and perceptual variables during infant development from the perspective of multistable competitive dynamic systems. Accordingly, behavioral modes and modes of perception compete with each other for activation. One and only one mode survives the mode-mode competition, which accounts for the incompatibility of modes being considered. However, the winning behavioral or perceptual state is not predefined. Rather, we argue that during particular stages of maturation multiple modes coexist for the same set of developmental, body-scaled, and environmental parameters or constraints. The winning behavioral or perceptual state depends on these pa...

Putting pubertal timing in developmental context: Implications for prevention

Developmental Psychobiology — Mon, 01 Mar 2010 00:00:00 +0100

This article examines selected findings regarding the consequences of difference in timing of pubertal onset in order to build an explanatory model of puberty in context. We also seek to shed light on possible prevention efforts targeting adolescent risk. To date, there is substantial evidence supporting early onset effects on both internalizing and externalizing problems during the adolescent decade and possibly beyond. However, such effects do not directly speak to preventive intervention. The biological, familial, and broader relationship contexts of puberty are considered along with unique contexts for early maturing girls versus boys. Finally, we identify potential strategies for intervention based on these explanatory models. © 2010 Wiley Periodicals, Inc. Dev Psychobiol (Source: De...

Adolescent risk taking, impulsivity, and brain development: Implications for prevention

Developmental Psychobiology — Sat, 20 Feb 2010 00:00:00 +0100

Individual differences in impulsivity underlie a good deal of the risk taking that is observed during adolescence, and some of the most hazardous forms of this behavior are linked to impulsivity traits that are evident early in development. However, early interventions appear able to reduce the severity and impact of these traits by increasing control over behavior and persistence toward valued goals, such as educational achievement. One form of impulsivity, sensation seeking, rises dramatically during adolescence and increases risks to healthy development. However, a review of the evidence for the hypothesis that limitations in brain development during adolescence restrict the ability to control impulsivity suggests that any such limitations are subtle at best. Instead, it is argued that ...

Epigenetic perspectives on development: Evolving insights on the origins of variation

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

The articles in this special section of Developmental Psychobiology explore topics discussed at the 24th Annual Winter Conference on Current Issues in Developmental Psychobiology held in January 2009 in St. Croix. The final session of the meeting: "Epigenetics and Behavioral Development Within and Across Generations" included discussion of several emerging issues relevant to the study of individual differences, parental influences on development, and the stability versus plasticity of the underlying mechanisms involved in behavioral variation. The contributions to this special section highlight the importance of the epigenetic regulation of gene expression to the field of developmental psychobiology and the critical role of these molecular mechanisms in mediating the interplay between gene...

Translating models of antisocial behavioral development into efficacious intervention policy to prevent adolescent violence

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

Adolescent chronic antisocial behavior is costly but concentrated in a relatively small number of individuals. The search for effective preventive interventions draws from empirical findings of three kinds of gene-by-environment interactions: (1) parenting behaviors mute the impact of genes; (2) genes alter the impact of traumatic environmental experiences such as physical abuse and peer social rejection; and (3) individuals and environments influence each other in a dynamic developmental cascade. Thus, environmental interventions that focus on high-risk youth may prove effective. The Fast Track intervention and randomized controlled trial are described. The intervention is a 10-year series of efforts to produce proximal change in parenting, peer relations, social cognition, and academic p...

Effects of postweaning social and physical deprivation on locomotor activity patterns and explorative behavior in female CD-1 mice

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

Social and physical deprivation during adolescence has detrimental consequences for brain maturation and cognitive functions. To test the hypothesis that social and physical deprivation during mouse adolescence would disrupt activity and exploration behavior, we exposed mice either to deprived or enriched rearing (postnatal days 21-60) and assessed activity and exploration of adult mice individually or in mixed treatment groups. In automated group compartments, deprived-reared mice displayed higher locomotor activity, reduced explorative behavior and shifted activity timing compared to enriched-reared mice. Contrastingly, distance and timing of wheel running were largely unaffected by deprived rearing. Our results demonstrate that postweaning social and physical deprivation has measurable ...

Adolescence: A central event in shaping stress reactivity

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

The magnitude and duration of the hormonal stress response change dramatically throughout an organism's lifespan. Although much is known about the factors that modulate stress reactivity during adulthood and how neonatal development and aging influence stress responsiveness, we know relatively little about how stress reactivity changes during the juvenile to adult transition. Recent studies in adolescent boys and girls have suggested that stress is an important factor contributing to an individual's vulnerability to various neuropsychological dysfunctions, including anxiety, depression, and drug abuse. Thus, understanding how exposure to stressors during this crucial period of development lead to negative consequences is of paramount importance. A growing body of literature indicates that ...

Epigenetic influence of social experiences across the lifespan

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

The critical role of social interactions in driving phenotypic variation has long been inferred from the association between early social deprivation and adverse neurodevelopmental outcomes. Recent evidence has implicated molecular pathways involved in the regulation of gene expression as one possible route through which these long-term outcomes are achieved. These epigenetic effects, though not exclusive to social experiences, may be a mechanism through which the quality of the social environment becomes embedded at a biological level. Moreover, there is increasing evidence for the transgenerational impact of these early experiences mediated through changes in social and reproductive behavior exhibited in adulthood. In this review, recent studies which highlight the epigenetic effects of ...

Prospective effects of post-bereavement negative events on cortisol activity in parentally bereaved youth

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the association between adverse childhood experiences, such as parental death, and mental and physical health problems. Recent research indicates that children who experience the death of a parent exhibit HPA axis dysfunction; however, the mechanisms underlying this association have not been explored. It is theorized that physiological dysregulation may result from exposure to stressful life events subsequent to parental death. The current study examined the prospective relations between negative events following parental death and cortisol activity in parentally bereaved youth. A greater number of post-bereavement negative events predicted significantly lower levels of cortisol activity 6 years later; th...

Animal models of early life stress: Implications for understanding resilience

Developmental Psychobiology — Fri, 19 Feb 2010 00:00:00 +0100

In the mid-1950s, Levine and his colleagues reported that brief intermittent exposure to early life stress diminished indications of subsequent emotionality in rats. Here we review ongoing studies of a similar process in squirrel monkeys. Results from these animal models suggest that brief intermittent exposure to stress promotes the development of arousal regulation and resilience. Implications for programs designed to enhance resilience in human development are discussed. © 2010 Wiley Periodicals, Inc. Dev Psychobiol (Source: Developmental Psychobiology)

How the epigenome contributes to the development of psychiatric disorders

Developmental Psychobiology — Wed, 03 Feb 2010 00:00:00 +0100

Epigenetics commonly refers to the developmental process by which cellular traits are established and inherited without a change in DNA sequence. These mechanisms of cellular memory also orchestrate gene expression in the adult brain and recent evidence suggests that the "epigenome" represents a critical interface between environmental signals, activation, repression and maintenance of genomic responses, and persistent behavior. We here review the current state of knowledge regarding the contribution of the epigenome toward the development of psychiatric disorders. © 2010 Wiley Periodicals, Inc. Dev. Psychobiol (Source: Developmental Psychobiology)

Development of role-differentiated bimanual manipulation during the infant's first year

Developmental Psychobiology — Tue, 02 Feb 2010 00:00:00 +0100

Role-differentiated bimanual manipulation (RDBM) is a complementary movement of both hands that requires differentiation between actions of the hands. Previous research showed that RDBM can be observed in infants as early as 7 months. However, RDBM could be considered a skill only when its frequency, duration, and use is appropriate for the type of manual task, and there is some evidence of intentionality in use. Twenty-four normally developing infants were studied longitudinally at 7, 9, 11, and 13 months to assess the frequency and duration of five clearly different types of RDBM with three "single-part" and three "two-part" toys as they emerge during development. Also, the sequences of actions that lead to RDBM were examined for evidence of "intentionality." The results show that althou...

A longitudinal study of emotion regulation and anxiety in middle childhood: Associations with frontal EEG asymmetry in early childhood

Developmental Psychobiology — Fri, 29 Jan 2010 00:00:00 +0100

We investigated whether brain electrical activity during early childhood was associated with anxiety symptoms and emotion regulation during a stressful situation during middle childhood. Frontal electroencephalogram (EEG) asymmetries were measured during baseline and during a cognitive control task at 4 ½ years. Anxiety and emotion regulation were assessed during a stressful situation at age 9 (speech task), along with measures of heart rate (HR) and heart rate variability (HRV). Questionnaires were also used to assess anxiety and emotion regulation at age 9. Results from this longitudinal study indicated that children who exhibited right frontal asymmetry in early childhood experienced more physiological arousal (increased HR, decreased HRV) during the speech task at age 9 and less abili...

Maternal voice and short-term outcomes in preterm infants

Developmental Psychobiology — Thu, 28 Jan 2010 00:00:00 +0100

This study explored effects of exposure to maternal voice on short-term outcomes in very low birth weight preterm infants cared for within an neonatal intensive care unit (NICU) without an ongoing program of developmental care. Using a comparative design, 53 infants born during their 27th to 28th postmenstrual week were sampled by convenience. Experimental groups were exposed to maternal voice during two developmental time periods. Group 1 listened to a recording of their mothers reciting a rhyme from 28 to 34 postmenstrual weeks. Group 2 waited 4 weeks and heard the recording from 32 to 34 weeks. The control group received routine care. The primary analysis of combined experimental groups compared to the control group revealed that the experimental infants experienced significantly fewer ...

Motherless rats show deficits in maternal behavior towards fostered pups

Developmental Psychobiology — Thu, 28 Jan 2010 00:00:00 +0100

Complete maternal deprivation in rats, through artificial rearing (AR), produces deficits in subsequent maternal behavior of the offspring. These deficits are partially reversed when isolated pups are provided with additional tactile stimulation designed to simulate maternal licking (e.g., Gonzalez et al. [2001] Developmental Psychobiology, 38, 11-32). These findings highlight the importance of the early maternal environment in subsequent development. However, given the possibility that prenatal environments may differ between AR and maternally reared (MR) offspring, the deficits in the behavior of AR mothers may be driven by the characteristics of their pups derived from the effects of an altered prenatal environment. Hence differences in the neonatal pups of AR mothers may produce the al...

Effects of excessive glucocorticoid receptor stimulation during early gestation on psychomotor and social behavior in the rat

Developmental Psychobiology — Wed, 20 Jan 2010 00:00:00 +0100

Severe psychological stress in the first trimester of pregnancy increases the risk of schizophrenia in the offspring. To begin to investigate the role of glucocorticoid receptors in this association, we determined the effects of the glucocorticoid dexamethasone (2 mg/kg), administered to pregnant rats on gestation days 6-8, on maternal behaviors and schizophrenia-relevant behaviors in the offspring. Dams receiving dexamethasone exhibited increased milk ejection bouts during nursing. Offspring of dexamethasone-treated dams (DEX) showed decreased juvenile social play and a blunted acoustic startle reflex in adolescence and adulthood, effects that were predicted by frequency of milk ejections in the dams. DEX offspring also showed increased prepulse inhibition of startle and reduced amphetami...

Cross-sectional analysis of the association between age and corpus callosum size in chimpanzees (Pan troglodytes)

Developmental Psychobiology — Wed, 20 Jan 2010 00:00:00 +0100

We report the first investigation into the development of the corpus callosum and its regional subdivisions in chimpanzees (Pan troglodytes). Magnetic resonance images were collected from 104 chimpanzees (female n = 63, male n = 41) ranging in age from 6 years (pre-pubescent period) to 54 years (old age). Sustained linear growth was observed in the area of the CC subdivision of the genu; areas of the posterior midbody and anterior midbody displayed nonlinear growth during development. After adjusting for total brain size, we observed linear growth trajectories of the total CC and CC subdivisions of the genu, posterior midbody, isthmus and splenium, and nonlinear growth trajectories of the rostral body and anterior midbody. These developmental patterns are similar to the development of the ...

Early life handling decreases serotonin turnover in the nucleus accumbens and affects feeding behavior of adult rats

Developmental Psychobiology — Sat, 09 Jan 2010 00:00:00 +0100

In our previous studies, we reported that neonatally handled rats have an increased ingestion of sweet food but are resistant to the damaging effects of a chronic exposure to a highly palatable diet. Accumbal serotonin (5-HT) is important for feeding behavior and plays a role in the vulnerability to diet-induced obesity. Therefore, our hypotheses were (1) 5-HT turnover in the nucleus accumbens is altered in neonatally handled animals and plays a role in their differential feeding behavior and (2) if this is so, a chronic pharmacological treatment affecting 5-HT reuptake (chronic imipramine) would be able to revert the behavioral findings. Litters were divided into nonhandled and handled (10 min/day, Days 1-10 after birth). In Experiment 1, we demonstrated that a decreased 5-HT metabolism i...

Visual stimulation enhances auditory processing in 3-month-old infants and adults

Developmental Psychobiology — Tue, 15 Dec 2009 00:00:00 +0100

Behavioral work demonstrates human infants are sensitive to a host of intersensory properties and this sensitivity promotes early learning and memory. However, little is known regarding the neural basis of this ability in infants. Using event-related potentials (ERPs) with infants and adults, we show that during passive viewing auditory evoked brain responses are increased with the presence of simultaneous visual stimulation. Results converge with previous adult neuroimaging studies, single-cell recordings in nonhuman animals, and behavioral studies with human infants to provide evidence for an elevated status of multisensory stimulation in infancy. Furthermore, these results may provide a neural marker of multisensory audio-visual processing in infants that can be used to test development...

The effect of taste familiarity on intake and taste reactivity in infant rats

Developmental Psychobiology — Mon, 14 Dec 2009 00:00:00 +0100

With infant rats, unlike with adults, increased intake of a taste after mere exposure to this stimulus is not consistently found; this has sometimes been interpreted as a failure by the immature subject to recognize tastes as familiar. We studied the effect of preexposure to a tastant, measuring taste reactivity and intake in 14-day-old rats. Familiarity increased hedonic response to sucrose, but also increased aversive response to quinine and ethanol. With the sucrose-quinine compound, familiarity increased both the hedonic and the aversive reaction to the stimulus. In no case was a differential reactivity to water observed. Significant increased intake after familiarization was only found with quinine or the sucrose-quinine compound. Results indicate that in infant rats, and with the pre...

Visual discrimination of male and female faces by infant rhesus macaques

Developmental Psychobiology — Tue, 24 Nov 2009 00:00:00 +0100

Recent studies have revealed that human infants process female faces differently from male faces. To test whether a similar preference for female faces exists in other primates, we presented nursery-reared infant rhesus macaques with photographs of macaque faces and human faces. At (Source: Developmental Psychobiology)

Change in imitation for object manipulation between 10 and 12 months of age

Developmental Psychobiology — Mon, 23 Nov 2009 00:00:00 +0100

In this study we tested one factor likely to contribute to this change: an increase in the capacity for observational learning, which may enable infants to learn new behaviors and practice ones that they already possess. Thus, we evaluated change in imitation between 10 and 12 months of age. Twelve 10-month-olds and twelve 12-month-old infants were shown different kinds of manual actions on a variety of objects; infants also manipulated objects during a free play control condition. Results indicated that older infants benefited more than younger ones in the Demonstration condition and that at both ages, infants performed the target action more quickly after observing a demonstration. We hypothesize that observational learning can help manual skill development by enabling infants to learn n...

Effect of prenatal and postnatal methamphetamine exposure on nociception in adult female rats

Developmental Psychobiology — Mon, 23 Nov 2009 00:00:00 +0100

This study indicates that postnatal but not prenatal exposure to MA affects nociception in adult female rats. However, it is still not clear whether the pro-nociceptive effect of postnatal MA exposure is linked to direct action of MA on neuronal organization, or to indirect action of MA mediated by impaired maternal care. © 2009 Wiley Periodicals, Inc. Dev Psychobiol (Source: Developmental Psychobiology)

The effects of stress on play and home cage behaviors in adolescent male rats

Developmental Psychobiology — Mon, 23 Nov 2009 00:00:00 +0100

One prominent feature of adolescence is the high frequency of social behaviors, such as play. Engaging in these behaviors appears necessary for proper socio-emotional development as social isolation during adolescence typically leads to behavioral dysfunctions in adulthood. The present experiments examined the effects of stress on social and nonsocial behaviors in group housed adolescent male rats. We found that acute restraint stress led to a complete inhibition of play (e.g., nape contacts and pins) and reduced social investigations in pre- (28 days), mid- (35 days), and late-adolescent (42 and 49 days) animals. A follow-up study, however, found that restraint-induced suppression of play and social investigations was transient such that experimental animals engage in these behaviors at l...

Sleep quality, cortisol levels, and behavioral regulation in toddlers

Developmental Psychobiology — Wed, 18 Nov 2009 00:00:00 +0100

This study examines the association between nighttime sleep characteristics and cortisol levels and how these variables relate to aspects of children's temperament and behavior. Twenty-seven healthy children, aged 12-36 months, attending group childcare settings, participated in the study. Each child's sleep was measured at home with actigraphy over three nights. Saliva samples were collected by the mothers at bedtime and within 30 min of awakening. In addition, both the mother and the daycare teacher rated the child's behavioral difficulties and negative emotionality. It was found that children with more fragmented sleep displayed higher awakening cortisol levels compared to children with more efficient sleep. Moreover, elevated awakening cortisol levels were correlated with teachers' rat...

Changes in mid-to-late latency auditory evoked reponses in the chicken during neural maturation

Developmental Psychobiology — Sat, 31 Oct 2009 00:00:00 +0100

Utilizing the special advantages offered by the protracted maturation of neural circuits in chicken forebrain this study investigates the functional consequence of maturation using auditory evoked response potentials (AERPs) in behaving animals. Repeated measures AERP recordings were undertaken between weeks 1 and 8 posthatch. Quantitative analysis revealed a significant decrease in amplitude of the positive AERP component and a decrease in latency of the negative AERP component with maturation. AERPs were also utilized to investigate perturbed maturation via the induction of chemically induced hypothyroidism. Results from this study showed that the induction of late onset hypothyroidism produces measurable effects on the chicken AERP consistent with perturbation in maturation of neuronal ...

Development of behavior in the litter huddle in rat pups: Within- and between-litter differences

Developmental Psychobiology — Thu, 29 Oct 2009 00:00:00 +0100

In conclusion, our study shows there to be consistent between-litter as well as within-litter differences in behavioral patterns during early life. These differences might have important implications for an individual's long-term behavioral and physiological performance. © 2009 Wiley Periodicals, Inc. Dev Psychobiol (Source: Developmental Psychobiology)

Dopamine receptors modulate ethanol's locomotor-activating effects in preweanling rats

Developmental Psychobiology — Mon, 19 Oct 2009 23:00:00 +0100

Near the end of the second postnatal week motor activity is increased soon after ethanol administration (2.5 g/kg) while sedation-like effects prevail when blood ethanol levels reach peak values. This time course coincides with biphasic reinforcement (appetitive and aversive) effects of ethanol determined at the same age. The present experiments tested the hypothesis that ethanol-induced activity during early development in the rat depends on the dopamine system, which is functional in modulating motor activity early in ontogeny. Experiments 1a and 1b tested ethanol-induced activity (0 or 2.5 g/kg) after a D1-like (SCH23390; 0, .015, .030, or .060 mg/kg) or a D2-like (sulpiride; 0, 5, 10, or 20 mg/kg) receptor antagonist, respectively. Ethanol-induced stimulation was suppressed by SCH23390...

Vocal and locomotor responses of piglets to social isolation and reunion

Developmental Psychobiology — Tue, 22 Sep 2009 23:00:00 +0100

Potentiation of infant isolation calls following a brief reunion with the mother is considered an index of filial bonding in altricial rodents. We investigated potentiation of isolation and reunion responses in 15-day-old unweaned domestic piglets (Sus scrofa domesticus). When piglets were re-isolated following a brief, comforting reunion with their mother and littermates in their home pen, they displayed a persistence (relative potentiation) of calling and jumping. In contrast, when re-isolated following a brief interaction with their mother or an unfamiliar sow in a familiar or unfamiliar location, or with littermates alone, calling rate and locomotion dropped. Subsequently, piglets spent more time near their mother's face if they had previously interacted with an unfamiliar sow rather t...

Hair cortisol predicts object permanence performance in infant rhesus macaques (Macaca mulatta)

Developmental Psychobiology — Mon, 21 Sep 2009 23:00:00 +0100

In this study we examined whether hair cortisol, an integrated measure of hypothalamic-pituitary-adrenal (HPA) axis functioning, predicted performance of nursery-reared (NR) infant rhesus monkeys (n = 32) on Piagetian object permanence tasks. Testing of NR infants began at 19.8 ± 2.2 (mean ± SE) days of age and continued for the next several months. Hair cortisol concentrations from the 32 NR monkeys were compared to those of 20 mother-peer-reared (MPR) infants. Hair was shaved at Day 14, allowed to regrow, and obtained again at month 6, thus representing integrated cortisol over a 5.5-month period of time. NR and MPR infants did not differ in month 6 hair cortisol values (t(50) = 0.02, p = 0.98). Linear regression revealed that hair cortisol predicted object permanence performance in th...

Atypical functional lateralization in children with fetal alcohol syndrome

Developmental Psychobiology — Fri, 18 Sep 2009 23:00:00 +0100

In order to explore effects of prenatal alcohol exposure on functional lateralization, item tasks measuring preferences of hand, foot, eye, and ear were administered to a sample of 23 children diagnosed with fetal alcohol syndrome (FAS) compared with typically developing (TD) children. In addition, a dichotic listening task was administered to a subsample of 11 children with FAS and a TD group of comparable age, sex and handedness. The children with FAS were characterized by increased nonright-handedness compared with TD children. No differences were evident for preferential use of foot, eye, or ear. Moreover, children with FAS displayed more right ear extinctions during dichotic listening relative to TD children, indicating a lack of right ear advantage. The results add to findings of dec...

Olfactory guidance of nipple attachment and suckling in kittens of the domestic cat: Inborn and learned responses

Developmental Psychobiology — Tue, 15 Sep 2009 23:00:00 +0100

In 60 kittens (11 litters) from free-ranging domestic cats we investigated the role of chemical cues in facilitating nipple attachment and suckling during the first month of postnatal life when kittens are totally dependent on the mother's milk. Kittens were tested both together and individually on sedated females in different reproductive states. We found (1) that newborn kittens with no suckling experience responded to the ventrum of lactating but not to the ventrum of nonlactating females with search behavior and attached to nipples within minutes; (2) that even in older kittens, nipple attachment depended on females' reproductive state, with virtually no attachments on nonreproducing females, some on pregnant females, the greatest number on early-lactating females, followed by a declin...

Sexually dimorphic effects of postnatal treatment on the development of activity-based anorexia in adolescent and adult rats

Developmental Psychobiology — Mon, 14 Sep 2009 23:00:00 +0100

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis is a marked feature of anorexia nervosa. Using a modified version of the activity-based animal model of anorexia nervosa, we examine whether factors known to affect HPA axis activity influence the development of activity-based anorexia (ABA). Male and female rats were subjected to maternal separation or handling procedures during the first two postnatal weeks and tested in a mild version of the ABA paradigm, comprised of 2-hr daily running wheel access followed by 1-hr food access, either in adolescence or adulthood. Compared to handled females, maternally separated females demonstrated greater increases in wheel running and a more pronounced running-induced suppression of food intake during adolescence, but not in adulthood. I...

Maternal prenatal anxiety, postnatal caregiving and infants' cortisol responses to the still-face procedure

Developmental Psychobiology — Tue, 08 Sep 2009 23:00:00 +0100

This study prospectively examined the separate and combined influences of maternal prenatal anxiety disorder and postnatal caregiving sensitivity on infants' salivary cortisol responses to the still-face procedure. Effects were assessed by measuring infant salivary cortisol upon arrival at the laboratory, and at 15-, 25-, and 40-min following the still-face procedure. Maternal symptoms of anxiety during the last 6 months of pregnancy were assessed using clinical diagnostic interview. Data analyses using linear mixed models were based on 88 women and their 7-month-old infants. Prenatal anxiety and maternal sensitivity emerged as independent, additive moderators of infant cortisol reactivity, F (3, 180) = 3.29, p = .02, F (3, 179) = 2.68, p = .05 respectively. Results were independent of mat...

Ontogeny of Rat Recognition Memory measured by the novel object recognition task

Developmental Psychobiology — Mon, 07 Sep 2009 23:00:00 +0100

Detection of novelty is an essential component of recognition memory, which develops throughout cerebral maturation. To better understand the developmental aspects of this memory system, the novel object recognition task (NOR) was used with the immature rat and ontogenically profiled. It was hypothesized that object recognition would vary across development and be inferior to adult performance. The NOR design was made age-appropriate by downsizing the testing objects and arena. Weanling (P20-23), juvenile (P29-40), and adult (P50+) rats were tested after 0.25, 1, 24, and 48 hr delays. Weanlings exhibited novel object recognition at 0.25 and 1 hr, while older animals showed a preference for the novel object out to 24 hr. These findings are consistent with previous research performed in huma...

Psychophysiological correlates of parenting behavior in mothers of young children

Developmental Psychobiology — Mon, 07 Sep 2009 23:00:00 +0100

This study investigated HPA and vagal functioning as correlates of parenting in mothers of 175 six-month-old children. Salivary cortisol indexed HPA functioning and respiratory sinus arrhythmia (RSA) reduction indexed vagal regulation. Positive engagement and negative intrusiveness were observed during the Face-to-Face Still Face Paradigm (FFSFP) reunion and a semi-structured free play episode. Mixed modeling was used to examine differences in maternal behaviors across contexts as a function of psychophysiology. Main effects of cortisol levels, as well as interactions with RSA reduction and context, predicted negative intrusiveness. Mothers with high cortisol exhibited more negative intrusiveness if they also had lower RSA reduction. Mothers were also less negatively intrusive during the F...

Heart rate variability in response to pain stimulus in VLBW infants followed longitudinally during NICU stay

Developmental Psychobiology — Mon, 07 Sep 2009 23:00:00 +0100

The objective of this longitudinal study, conducted in a neonatal intensive care unit, was to characterize the response to pain of high-risk very low birth weight infants ( (Source: Developmental Psychobiology)

Abstracts: International Society for Developmental Psychobiology, 42nd annual meeting, October 14-17, 2009 Chicago, IL

Developmental Psychobiology — Wed, 02 Sep 2009 23:00:00 +0100

No Abstract. (Source: Developmental Psychobiology)

Long maternal separation has protective effects in rats exposed to activity-based anorexia

Developmental Psychobiology — Tue, 01 Sep 2009 23:00:00 +0100

In conclusion, prolonged maternal separation appears to promote resistance in female animals subjected to harsh ABA life-threatening conditions. © 2009 Wiley Periodicals, Inc. Dev Psychobiol (Source: Developmental Psychobiology)

Genetic effects on infant handedness under spatial constraint conditions

Developmental Psychobiology — Tue, 01 Sep 2009 23:00:00 +0100

Previous studies have reported a genetic influence on the individual differences in adult handedness; however, relatively little is known about genetic influences on the development of infant hand selection. In the current study, we examined whether genetic influences on handedness are expressed in various spatial locations in infants aged 18 months using the twin method. Infants were asked to respond to targets positioned in left, middle, and right locations using grasping movements. Results showed that similarities in hand selection within monozygotic twin pairs was more than two times higher than that of the dizygotic twin pairs in the middle location. In the left location, similarities in hand selection within monozygotic and dizygotic twin pairs were low. In addition, low individual d...

Environmental enrichment influences survival rate and enhances exploration and learning but produces variable responses to the radial maze in old rats

Developmental Psychobiology — Mon, 31 Aug 2009 23:00:00 +0100

Wistar rats at 7 (mature), 16 (aging), and 22 (old) months of age spent 70 days in normal laboratory (Social), impoverished (Isolated) or dynamic Enrichment cages. The Enriched cage emphasized spatial re-arrangements of significant items, and the learning of new routes. Subsequently, Enriched rats at all ages entered a novel environment and escaped from a bright light with significantly shorter latencies than rats from either of the other environments. Mature, aging and some of the old Enriched rats also significantly outperformed their Isolated and Social counterparts in the radial maze. However old Enriched and Isolated animals showed significant variability in relation to the measure of the proportion reaching criterion on this task, and a significantly lower proportion than of old Soci...

Regional Fos expression induced by morphine withdrawal in the 7-day-old rat

Developmental Psychobiology — Tue, 25 Aug 2009 23:00:00 +0100

Human infants are often exposed to opiates chronically but the mechanisms by which opiates induce dependence in the infant are not well studied. In the adult the brain regions involved in the physical signs of opiate withdrawal include the periaqueductal gray area, the locus coeruleus, amygdala, ventral tegmental area, nucleus accumbens, hypothalamus, and spinal cord. Microinjection studies show that many of these brain regions are involved in opiate withdrawal in the infant rat. Our goal here was to determine if these regions become metabolically active during physical withdrawal from morphine in the infant rat as they do in the adult. Following chronic morphine or saline treatment, withdrawal was precipitated in 7-day-old pups with the opiate antagonist naltrexone. Cells positive for Fos...

Prenatal maternal emotional complaints are associated with cortisol responses in toddler and preschool aged girls

Developmental Psychobiology — Sun, 16 Aug 2009 23:00:00 +0100

Associations between prenatal maternal emotional complaints and child behavioral and cognitive problems have been reported, with different relations for boys and girls. Fetal programming hypotheses underline these associations and state that the early development of the HPA-axis of the children may have been affected. In the present study, differences in cortisol responses of prenatally exposed and nonexposed children are examined for both sexes separately. Cortisol response patterns of a group preschool aged children that were prenatally exposed to high levels of maternal emotional complaints (N = 51) were compared to a nonexposed group (N = 52). Child saliva was collected at the start of a home visit (T1), 22 min after a mother-child interaction episode (T2), and 22 min after a potential...

Neural correlates of successful and partial inhibitions in children: An ERP study

Developmental Psychobiology — Fri, 14 Aug 2009 23:00:00 +0100

This experiment used event-related potentials (ERPs) to investigate the neural processes underlying the development of response inhibition in a modified version of the go/no-go paradigm [Cragg and Nation [2008] Developmental Science 11(6): 819-827]. N2 and P3 ERP components on correct go trials and partial and successful inhibitions were compared in 7- and 9-year-old children. A larger N2 effect on successful inhibitions was found in 9-year-olds compared to 7-year-olds at fronto-central electrodes. N2 amplitude was positively related to behavioral performance in the 7-year-olds suggesting it may reflect inhibitory processes; however, this relationship was not present in the 9-year-olds. Age differences were also apparent in the go P3, perhaps indicating differences in stimulus processing. ...

Inhibited temperament and parent emotional availability differentially predict young children's cortisol responses to novel social and nonsocial events

Developmental Psychobiology — Wed, 12 Aug 2009 23:00:00 +0100

Preschool-aged children (n = 274) were examined in the laboratory to assess behavioral and cortisol responses to nonsocial and social threat. Parents also responded to scales on the Children's Behavior Questionnaire reflecting exuberant approach to novel/risky activities (reversed scored) and shyness. Multi-method measures of Nonsocial and Social Inhibition were computed. Parents and children were observed engaging in a series of interactive tasks and the Emotional Availability scales were scored for parental sensitivity, nonintrusiveness, nonhostility, and structuring. These scores were factored to yield one measure of Parenting Quality. Analyses revealed that Nonsocial and Social Inhibition could be distinguished and that associations with cortisol response were stressor specific. Modera...

Fetal motor activity and maternal cortisol

Developmental Psychobiology — Thu, 23 Jul 2009 23:00:00 +0100

The contemporaneous association between maternal salivary cortisol and fetal motor activity was examined at 32 and 36 weeks gestation. Higher maternal cortisol was positively associated with the amplitude of fetal motor activity at 32 weeks, r(48) = .39, p < .01, and 36 weeks, r(77) = .27, p < .05, and the amount of time fetuses spent moving at 32 weeks during the 50 min observation period, r(48) = 33, p < .05. Observation of periods of unusually intense fetal motor activity were more common in fetuses of women with higher cortisol, Mann-Whitney U = 58.5. There were no sex differences in fetal motor activity, but the associations between maternal cortisol and fetal motor amplitude and overall movement were significantly stronger for male than female fetuses. © 2009 Wiley Periodicals, Inc....

Stability of resting frontal electroencephalogram (EEG) asymmetry and cardiac vagal tone in adolescent females exposed to child maltreatment

Developmental Psychobiology — Wed, 22 Jul 2009 23:00:00 +0100

The experience of child maltreatment is a known risk factor for the development of psychopathology. Structural and functional modifications of neural systems implicated in stress and emotion regulation may provide one mechanism linking early adversity with later outcome. The authors examined two well-documented biological markers of stress vulnerability [resting frontal electroencephalogram (EEG) asymmetry and cardiac vagal tone] in a group of adolescent females exposed to child maltreatment (n = 38; M age = 14.47) and their age-matched non-maltreated (n = 25; M age = 14.00) peers. Maltreated females exhibited greater relative right frontal EEG activity and lower cardiac vagal tone than controls over a 6-month period. In addition, frontal EEG asymmetry and cardiac vagal tone remained stabl...

Genetic and gene-environment interaction effects on preschoolers' social behaviors

Developmental Psychobiology — Mon, 06 Jul 2009 23:00:00 +0100

This study examined effects from a specific dopamine receptor gene (DRD4), environmental influences from parents and peers, and the interaction between them, on aggressive and prosocial behaviors of preschoolers. Children were classified as DRD4-L (n = 27) if they had at least one DRD4 allele with six to eight repeats and as DRD4-S (n = 35) if not. Parent-child interactions were coded when children were 3-4 years old. Peer interaction data and parent questionnaires were collected at age 5. DRD4-L children shared less with each other and parents were less sensitive during parent-twin triadic interactions. Also, genotype interacted with peer aggression to affect children's aggression during a peer play interaction at age 5, and genotype interacted with prior parental sensitivity to affect la...

Development of dynamic stability in children's rhythmic movement

Developmental Psychobiology — Sun, 05 Jul 2009 23:00:00 +0100

This study examined the hypothesis that the stability of rhythmic motor patterns increases with developmental age in children. Children aged 6 and 10 years and adults (18- to 23-year-olds) rocked back and forth at their preferred amplitude and frequency while seated on a wooden box placed atop a force platform. Participants performed the seated rocking task with their feet supported and unsupported. There was an age-related decrease in rocking frequency and variability of the rocking cycle period, while the stability of the rocking dynamics increased, as indexed by the standard deviation of the phase angle of center of pressure motion. The presence of foot support decreased the stability of the rocking dynamics and reduced cycle period variability in the children, but not the adults. The r...

Olfactory learning in the rat immediately after birth: Unique salience of first odors

Developmental Psychobiology — Sun, 05 Jul 2009 23:00:00 +0100

An infant rat's chance of survival is increased when it remains close to the nest. Early olfactory learning supports such adaptive behavior. Previous experiments indicated that non-associative odor exposure immediately after birth promoted later attachment to a similarly scented artificial nipple. The goal of the current experiments was to extend these findings on olfactory learning in the hours after birth by: exposing pups to more than one odor exposure (Experiment 1), dissecting the role of timing versus order of odor exposure (Experiment 2), testing the odor specificity of these effects (Experiments 3 and 4), and evaluating associative odor conditioning soon after birth (Experiment 5). Without explicit prior odor experience, pups only hours old do not respond much to a novel odor. Prio...

The ontogeny of exploratory behavior in male and female adolescent rats (Rattus norvegicus)

Developmental Psychobiology — Sun, 05 Jul 2009 23:00:00 +0100

During adolescence, rats gain independence from their mothers and disperse from the natal burrow, with males typically dispersing further than females. We predicted that, if dispersal patterns are associated with responsiveness to novelty, exploratory behavior in novel environments would increase across adolescence, and males would explore more than females. Alternatively, females might explore more than males, if females are more motivated than males to learn about the immediate environment or if females have poorer spatial abilities than males. Twenty-five male and 21 female rats were exposed to two novel environments (open field and elevated plus-maze) during early, mid-, or late adolescence. Total locomotion and amount of exploration directed towards aversive areas increased across ado...

Temperament does not affect the overall establishment of mutual preference between the mother and her young in sheep measured in a choice test

Developmental Psychobiology — Mon, 15 Jun 2009 04:00:00 +0100

Temperament influences maternal behavior and lamb survival in Merino sheep selected for calm or nervous temperament. The impact of this selection on mother-young recognition and early expression of temperament in lambs is unknown. We tested the ability of multiparous ewes selected for calm (n = 16) or nervous (n = 18) temperament to recognize their own lambs 6 hr after parturition, the ability of the lambs to display a preference for their own mother at 18 hr, and the temperament of the lambs at 1 and 16 weeks of age. Ewes and lambs from both genotypes showed a similar preference for their familiar kin. In contrast, differences in temperament were detectable at 1 and 16 weeks of age. Nervous lambs showed higher vocal and locomotor activity than calm lambs. Thus, temperament did not affect ...

Long-term effects of neonatal handling on mu-opioid receptor levels in the brain of the offspring

Developmental Psychobiology — Tue, 09 Jun 2009 04:00:00 +0100

Neonatal handling is an experimental paradigm of an early experience which permanently alters hypothalamic-pituitary-adrenal axis function resulting in increased ability to cope with stress, and decreased emotionality. In the present work we investigated the effect of neonatal handling on adult rat brain mu-opioid receptor levels, since the opioid system is known to play an important role in emotional processing, anxiety and stress responses. Neonatal handling resulted in increased levels of mu-opioid receptors in the basolateral and central amygdaloid nuclei, in the CA3 and CA4 hippocampal areas, in the ventral tegmental area, the nucleus accumbens and the prefrontal cortex. Handled animals of both sexes had lower anxiety as measured in the elevated plus maze. The increased mu receptor le...

Changes in hyporesponsiveness to acute amphetamine and age differences in tyrosine hydroxylase immunoreactivity in the brain over adolescence in male and female rats

Developmental Psychobiology — Wed, 03 Jun 2009 04:00:00 +0100

We investigated hyposensitivity after amphetamine in early (postnatal Day 30; P30) and late (P45) adolescent rats compared to adults (P70) in experiment 1. Locomotor activity was measured for 1 hr after the first (acute) and second (24 hr later) injection of amphetamine (0.5 or 1.5 mg/kg). P30 and P45 rats were transiently hypoactive compared to adults, as indicated by reduced locomotor activity after acute amphetamine and enhanced activity after the second injection in adolescents only. In experiment 2, ovariectomy did not alter locomotor activity during habituation at any age compared to intact rats, and, as for intact adolescents, ovariectomized adolescents continued to be less active after amphetamine than adults, suggesting gonadal immaturity alone cannot account for age differences i...

Alpha-melanocyte-stimulating hormone attenuates behavioral effects of corticotropin-releasing factor in isolated guinea pig pups

Developmental Psychobiology — Tue, 02 Jun 2009 04:00:00 +0100

During a 3-hr period of social isolation in a novel environment, guinea pig pups exhibit an initial active phase of behavioral responsiveness, characterized primarily by vocalizing, which is then followed by a stage of passive responsiveness in which pups display a distinctive crouch, eye-closing, and extensive piloerection. Prior treatment of pups with alpha-melanocyte-stimulating hormone ([alpha]-MSH) reduces each of the passive behaviors. The onset of passive responding during separation can be accelerated with peripheral injection of corticotropin-releasing factor (CRF). To examine whether CRF produces its effects through a mechanism similar to that of prolonged separation, we examined the effect of administering [alpha]-MSH to pups injected with CRF. As expected, CRF markedly enhanced...

Behavioral response to methylphenidate challenge: Influence of early life parental care

Developmental Psychobiology — Tue, 02 Jun 2009 04:00:00 +0100

Rat studies have shown that pups subjected to suboptimal rearing conditions exhibited permanently dysregulated dopamine activity and altered behavioral responses to dopamine stimulation. In humans, heightened stress-induced mesoaccumbens dopamine release in adults reporting low maternal care experience has been shown. We explored the relationship between quality of parental care and behavioral responsivity to reward and 20 mg of the dopamine agonist methylphenidate (MPH). Forty-three male university students accomplished a monetarily rewarded card-sorting task in a placebo controlled between-subjects study design. In participants scoring above the cut-off score for high parental care as assessed by the Parental Bonding Inventory, MPH decreased performance accuracy in the reward condition o...

Long-term effects of infant learning on adult conditioned odor aversion are determined by the last preweaning experience

Developmental Psychobiology — Thu, 07 May 2009 04:00:00 +0100

We recently showed that odorizing mother's nipples from birth to weaning attenuated adult conditioned odor aversion (COA). The present study evaluated whether shorter durations of preweaning olfactory experiences could induce similar long-term effects. We first showed that late preweaning odorization (PN13-PN25) impaired adult COA similarly to odorization from birth to weaning (PN0-PN25) whereas early odorization (PN0-PN12) had no effect on adult COA. As early odorization was followed by an odorless suckling period, we evaluated whether this odorless suckling could have interfered with early associative learning. We therefore weaned the animals either immediately after early odorization or 7 days later. Early odorization (PN0-PN18) followed by late odorless suckling (PN19-PN25) had no effe...

Early independent walking: A longitudinal study of load perturbation effects

Developmental Psychobiology — Mon, 13 Apr 2009 04:00:00 +0100

This study investigated infants' ability to adapt to experimentally induced changes in their body dimensions at walk onset, and how this ability is affected by increased walking experience. Fifteen infants were studied over their first 6 months of independent walking with a load perturbation design. They traversed a walkway with loads symmetrically placed around the shoulders, waist, or ankles, and without loading. At walk onset, infants fell more with shoulder and ankle loads than with waist or no loads. Shoulder loads further resulted in higher walking speed and longer steps, while waist loads resulted in increased walking speed and larger foot rotation. Ankle loads disrupted walking proficiency the most, as indicated by lower walking speed, shorter steps, larger foot rotation, and small...

Detection of salivary oxytocin levels in lactating women

Developmental Psychobiology — Mon, 13 Apr 2009 04:00:00 +0100

This study also supports the potential usefulness of salivary measures of oxytocin as a noninvasive index of changes in this peptide. © 2009 Wiley Periodicals, Inc. Dev. Psychobiol 51: 367-373, 2009. (Source: Developmental Psychobiology)

Examining maternal influence on OLETF rats' early overweight: Insights from a cross-fostering study

Developmental Psychobiology — Mon, 13 Apr 2009 04:00:00 +0100

Obese female Otsuka Long Evans Tokushima Fatty (OLETF) rats display increased nursing time and frequency compared to lean LETO controls, suggesting a maternal contribution to pup preobesity. In previous studies, OLETF pups presented high adiposity, showed greater suckling efficiency, initiative and weight gain from nursing than controls throughout lactation. To further elucidate maternal-infant interactions contributing to pup preobesity, we cross-fostered pups a day after birth and examined maternal behavior. Nursing frequency decreased in OLETF dams raising LETO pups (OdLp) in the third postnatal week, while LETO dams raising OLETF pups showed no significant changes. Fat % was greater in the milk of OLETF versus LETO dams. OdLp pups showed long-term body weight (BW) increase, suggesting ...

Maternal care affects the development of maternal behavior in inbred mice

Developmental Psychobiology — Mon, 13 Apr 2009 04:00:00 +0100

The present study investigated the effects of variations in maternal behavior on the development of maternal behavior of female offspring in BALB/c and CBA/Ca inbred mice. In Experiment 1, we conducted fostering within or between the two strains and observed the maternal behaviors of mothers and female offspring for 2 weeks postpartum. Although fostering changed the maternal behavior of mothers in both strains, CBA mothers generally showed greater frequency of nursing posture and pup licking than BALB mothers. BALB female offspring reared by CBA mothers showed more body licking than those reared by BALB mothers, whereas fostering did not affect the maternal behavior of CBA female offspring. In Experiment 2, we examined the maternal behavior of females of F1 hybrids derived from reciprocal ...

A new approach for exploring functional development of fetal brain pathways

Developmental Psychobiology — Thu, 09 Apr 2009 04:00:00 +0100

Study of functional development of central pathways in fetuses is challenging due to the lack of methods available. In this article, we present a novel approach to test if and when central functional pathways are established by a combination of mapping with c-fos and chronically cannulated fetuses in utero. This approach is based on brain structures such as circumventricular organs (CVOs) that lack the blood-brain barrier (BBB), but are rich in sensors to peripheral signals and contain projections to other brain regions. If signaling molecules in the blood that are too large to cross the BBB induced c-fos expression in both the CVOs and other nuclei inside the fetal brain, this can be evidence that projections from the CVOs to those nuclei are established and functional. This is a useful r...

Olfactory association learning and brain-derived neurotrophic factor in an animal model of early deprivation

Developmental Psychobiology — Thu, 26 Mar 2009 04:00:00 +0100

Animal models can serve to explore neural mechanisms underlying the effects of stressful early experiences on behaviors supporting attachment. Neonatal rats primarily use olfaction for attachment, and Brain-Derived Neurotrophic Factor (BDNF) may be a key transcription target in olfactory association learning. In this experiment, neonatal male and female rats were isolated individually for 3 hr daily in the first week of life while their dams were left with partial litters (Early Deprivation, ED) or remained undisturbed (Control). At 1 week of age, subjects were tested using a 2-day classical conditioning paradigm. The conditioned group (O/M) was exposed to a novel odor paired with a milk infusion. Three additional groups included an unpaired odor and milk exposure group (O/M unP), an odor ...

Social motivation affects the display of individual discrimination in young and adult japanese quail(Coturnix japonica)

Developmental Psychobiology — Wed, 11 Mar 2009 04:00:00 +0100

A simultaneous two-choice test was used to investigate discrimination between a familiar (F) and an unfamiliar conspecific (U) in Japanese quail, selected for high (HSR) or low (LSR) social reinstatement behavior (tendency to rejoin and stay close to conspecifics). Animals were 1-week unsexed and 6-week-old male quail. One-week-old LSR quail and 6-week-old male HSR quail displayed discrimination after 24 hr of pair contact (p < 0.05), and a tendency to discriminate (p < 0.10) was found in adult male LSR quail. After 1 week of pair contact, results were similar in LSR quail chicks, but no discrimination was evidenced in adult quail of either line. Therefore, Japanese quail are able to discriminate between a familiar cagemate and an unfamiliar conspecific after only 24 hr of pair contact. Mo...

Nipple preference and contests in suckling kittens of the domestic cat are unrelated to presumed nipple quality

Developmental Psychobiology — Wed, 04 Mar 2009 05:00:00 +0100

We studied the development of suckling behavior and weight gain in 11 litters (52 kittens) of free-ranging domestic cats until postnatal day 28 just before the start of weaning. In six of these litters, we also recorded milk intake and contests for access to nipples. Already within 12 hr of birth kittens showed a preference for posterior nipples, and by postnatal day 3 each had developed a preference for particular nipples. In fact, 86% of kittens used one particular nipple most often, and even when the mother changed the side she lay on to nurse. Contests for access to nipples occurred throughout the study period at an average rate of one to two contests per kitten per hour of nursing. Contrary to suggestions in the literature that kittens compete for more productive nipples, we found no ...

Effects of alcohol and smoking during pregnancy on infant autonomic control

Developmental Psychobiology — Sat, 28 Feb 2009 05:00:00 +0100

Prenatal exposure to smoking and alcohol increases the risk for Sudden Infant Death Syndrome (SIDS). Physiological changes associated with these exposures are not well studied. Full-term infants were tested within the first 3 days of life. We hypothesized that maternal alcohol consumption and/or smoking during pregnancy would alter autonomic nervous system function. Newborns whose mothers smoked during pregnancy had lower beat-to-beat heart rate variability in quiet sleep. Infants whose mothers consumed alcohol had lower global heart rate variability, but only in active sleep. Unexposed infants demonstrated increases in heart rate with head-up tilt and decreases in heart rate with head-down tilt, but smoking and alcohol-exposed infants showed no significant responses. These results indicat...

Brainstem mechanisms underlying the sudden infant death syndrome: Evidence from human pathologic studies

Developmental Psychobiology — Tue, 24 Feb 2009 05:00:00 +0100

The brainstem hypothesis is one of the leading hypotheses concerning the sudden infant death syndrome (SIDS). It states that SIDS, or an important subset of SIDS, is due to abnormal brainstem mechanisms in the control of respiration, chemosensitivity, autonomic regulation, and/or arousal which impairs the infant's response to life-threatening, but often occurring, stressors during sleep (e.g., hypoxia, hypercarbia, asphyxia, hyperthermia) and leads to sudden death in a vulnerable developmental period. In this review, we summarize neuropathologic evidence from SIDS cases that support this hypothesis, beginning with the seminal report of subtle brainstem gliosis three decades ago. We focus upon recent neurochemical studies in our laboratory concerning the neurotransmitter serotonin (5-HT) an...

What Is the mechanism of SIDS? Clues from epidemiology

Developmental Psychobiology — Wed, 18 Feb 2009 05:00:00 +0100

The cause of sudden infant death syndrome (SIDS) is unknown. Many mechanisms have been postulated, although thermal stress, rebreathing of expired gases and infection/inflammation seem the most viable hypotheses for the causation of SIDS. Deaths from SIDS have reduced dramatically following the recommendation not to place infants to sleep prone. Epidemiological data have shown that prone sleeping position is more risky in winter, colder latitudes, higher altitudes, if the infant is unwell or has excessive bedding or clothing. This suggests prone sleeping position involves either directly or indirectly a thermal mechanism. SIDS caused by an infective/inflammatory mechanism might be associated with deaths occurring during the night. Rebreathing of expired gases, airway obstruction, long QT s...

Sudden infant death syndrome: A developmental psychobiologist's perspective

Developmental Psychobiology — Wed, 11 Feb 2009 05:00:00 +0100

No Abstract. (Source: Developmental Psychobiology)

A history of iron deficiency anemia during infancy alters brain monoamine activity later in juvenile monkeys

Developmental Psychobiology — Fri, 06 Feb 2009 05:00:00 +0100

Both during and after a period of iron deficiency (ID), iron-dependent neural processes are affected, which raises the potential concern that the anemia commonly experienced by many growing infants could have a protracted effect on the developing brain. To further investigate the effects of ID on the immature brain, 49 infant rhesus monkeys were evaluated across the first year of life. The mothers, and subsequently the infants after weaning, were maintained on a standardized diet containing 180 mg/kg of iron and were not provided other iron-rich foods as treats or supplements. As the infants grew, they were all screened with hematological tests, which documented that 16 (33.3%) became markedly ID between 4 and 8 months of age. During this anemic period and subsequently at 1 year of age, ce...

Early lead exposure effects on an auditory threshold task in the rhesus monkey (Macaca mulatta)

Developmental Psychobiology — Thu, 15 Jan 2009 05:00:00 +0100

Behavioral thresholds to pure tones were obtained from adult rhesus monkeys that had been exposed to lead during early development and unexposed cohort controls. Thresholds were elevated (by 2-9 dB) for the previously lead exposed monkeys at all frequencies tested (125-8,000 Hz in octave steps). Although the magnitude and direction of the differences were similar to significant effects reported for children, the more difficult task and much smaller sample sizes in this study of monkeys may have precluded obtaining significant differences at the same magnitude of effects observed in children. Thresholds for one lead-exposed monkey were significantly elevated at midrange frequencies in agreement with electrophysiological results obtained in another study [Lasky, Maier, Snodgrass, Hecox, and ...

Development of olfactory ability in children: Sensitivity and identification

Developmental Psychobiology — Thu, 08 Jan 2009 05:00:00 +0100

This study assessed the influence of school level and gender on odor sensitivity and identification, and the role of verbal capacity on odor identification in children (4-12 years) by using a revised version of an olfactory test designed for adults [Rouby et al. (1997). Connaissance et reconnaissance d'une série olfactive chez l'enfant préscolaire. Enfance, 1, 152-171]. We found that odor sensitivity and identification scores increased with school level, and that identification performance was better in girls than in boys. However, when we controlled verbal ability, the gender differences disappeared and the school level differences remained. This result indicates that the effect of gender on identification was probably due to the greater verbal ability of girls rather than to their grea...

Adolescent female rats are more resistant than males to the effects of early stress on prefrontal cortex and impulsive behavior

Developmental Psychobiology — Tue, 06 Jan 2009 05:00:00 +0100

We tested the hypothesis that adolescent Sprague-Dawley females may be more resistant than males to display impulsive behavior and lower prefrontal cortex thickness after mother-infant separation (MS). Starting at postnatal day 2 (P2), the MS group was separated 6 hr/day and the early handled (EH) group 15 min/day for 10 days, and another group was standard facility reared (SFR). Subjects were examined for novel open-field activity (P28), light-dark apparatus (P29), familiar open-field (P30) and frontal cortical thickness. This protocol resulted in impulsive behavior in MS rats relative to EH and SFR, but this effect was less pronounced in females than males. MS affected the two sexes differently in terms of decreased prefrontal cortex dorsoventral thickness, with this effect being signifi...

Respiratory sinus arrhythmia and cognitive functioning in children

Developmental Psychobiology — Wed, 24 Dec 2008 05:00:00 +0100

We examined associations between children's cognitive performance and both basal respiratory sinus arrhythmia (RSA) and RSA regulation to a reaction time task. Cognitive performance was examined in the lab via standardized tests of cognitive functioning (Woodcock-Johnson III) and a reaction time task. Results suggest that a higher level of basal RSA is predictive of better performance on WJ III scales examining fluid intelligence (e.g., working memory, cognitive efficiency). RSA reactivity was not significantly related to cognitive performance. Results build on and extend the literature by demonstrating that, in typically developing elementary school age children, RSA is related to well-standardized measures of cognitive performance even after controlling for potential confounds. © 2008 W...

Effects of litter-overlapping on emotionality, stress response, and reproductive functions in male and female rats

Developmental Psychobiology — Thu, 18 Dec 2008 05:00:00 +0100

In rats, mating at postpartum estrus and delayed dispersal of the young would result in the overlapping of two different-age litters. As a consequence, newborn pups' early experience will include not only that acquired during the interaction with the mother and age-matched littermates, but also with older siblings. As early-life experience modulates rodents' brain function, behavior and reproduction, we aimed to assess how changes in the early environment provoked by the overlapping of litters would affect emotionality, stress response and reproductive functions of male and female pups during adulthood. Results showed that both male and female overlapped reared pups exhibited a reduced behavioral inhibition in the open field test during adulthood. In addition, overlapped reared adult femal...

Sensitivity of the rate of spontaneous eye blinking to type of stimuli in young infants

Developmental Psychobiology — Sun, 07 Dec 2008 05:00:00 +0100

Although progress has been made toward understanding the mechanisms of spontaneous eye blinking (SB), few reports focus on the ontogeny of SB. The purpose of the present work was to investigate SB in infants by attempting to manipulate SB and examine potential correlates of SB. Fifty-two infants were observed in a quiet baseline condition then presented with either moving stimuli or a social stimulus. SB, eye movement, body movement and various background variables were measured. Results demonstrate that SB can be manipulated and that SB rate is differentially sensitive to the type of stimulus presented. Eye and body movements did not systematically relate to the rate of SB. Implications for mechanisms of SB regulation are discussed. © 2008 Wiley Periodicals, Inc. Dev Psychobiol (Source: ...

Genetic and littermate influences on yawning in two selectively bred strains of rats

Developmental Psychobiology — Sat, 29 Nov 2008 05:00:00 +0100

This study was made to separate genetic from postnatal maternal influences on yawning in two strains of Sprague-Dawley rats selected for high- (HY) and low-yawning frequency (LY). Foster mothers of the two strains reared litters of pups in the four possible combinations and yawning was recorded in a novel environment when the adult offspring were 75-day-old. Yawning frequency of males and females was affected by pup strain but not by the strain of the foster mothers, when litter size was made constant; HY adult offspring yawned more than LY adult offspring. Yawning frequency was higher in HY male offspring than in HY female offspring. An interaction term between pup sex and the strain of the foster mothers revealed that while males reared by LY mothers yawned more than males reared by HY m...

Greater intrasex phenotype variability in males than in females is a fundamental aspect of the gender differences in humans

Developmental Psychobiology — Sun, 23 Nov 2008 05:00:00 +0100

Human studies of intrasex variability have shown that males are intellectually more variable. Here we have performed retrospective statistical analysis of human intrasex variability in several different properties and performances that are unrelated or indirectly related to intelligence: (a) birth weights of nearly 48,000 babies (Medical Birth Registry of Norway); (b) adult weight, height, body mass index and blood parameters of more than 2,700 adults aged 18-90 (NORIP); (c) physical performance in the 60 meter dash event of 575 junior high school students; and (d) psychological performance reflected by the results of more than 222,000 undergraduate university examination grades (LIST). For all characteristics, the data were analyzed using cumulative distribution functions and the resultan...

Dopamine's role in social modulation of infant isolation-induced vocalization: II. Maternally modulated infant separation responses are regulated by D1- and D2-family dopamine receptors

Developmental Psychobiology — Fri, 21 Nov 2008 05:00:00 +0100

Mammalian infant behavior directed toward caregivers is critical to survival and may play a role in establishing social bonds. Most mammalian infants vocalize when isolated. Rat pups vocalize at a higher rate when isolated following an interaction with an adult female than after an interaction with littermates, a phenomenon termed maternal potentiation. We previously reported that the D2 receptor family agonist quinpirole disrupts maternal potentiation at a dose that does not alter vocalization rate following contact with littermates. Here we further examine the role of dopamine in maternal potentiation by testing effects of both D1 and D2 receptor family ligands, alone and in combination, on maternal potentiation. We tested the drugs' effects on isolation vocalization subsequent to litter...

Enhancement of attachment and cognitive development of young nursery-reared chimpanzees in responsive versus standard care

Developmental Psychobiology — Wed, 19 Nov 2008 05:00:00 +0100

Forty-six nursery-reared chimpanzee infants (22 females and 24 males) receiving either standard care (n = 29) or responsive care (n = 17) at the Great Ape Nursery at Yerkes participated in this study. Standard care (ST) consisted primarily of peer-rearing, with humans providing essential health-related care. Responsive care (RC) consisted of an additional 4 hr of interaction 5 days a week with human caregivers who were specially trained to enhance species-typical chimpanzee socio-emotional and communicative development. At 9 months, ST and RC chimpanzees were examined with the Bayley Scales for Infant Development to assess their Mental Development Index (MDI). At 12 months, the chimpanzees were assessed with their human caregivers in the Ainsworth Strange Situation Procedure (SSP). In this...

Peculiar modulation of taste aversion learning by the time of day in developing rats

Developmental Psychobiology — Mon, 17 Nov 2008 05:00:00 +0100

The ontogeny of the temporal context modulation of conditioned taste aversion was studied in male Wistar rats using a palatable 1% NaCl solution. A procedure that included two saline preexposures, a single pairing saline-lithium chloride (0.15 M; 1% b.w.) either at the same or a different time of day of preexposures and a one-bottle test at the same time than preexposure was applied. Four age groups (PN32, PN48, PN64, and PN100) covering the complete range from adolescence to the adult period were tested. The results showed no effect of a temporal context shift in PN32. A peculiar enhancement of temporal context-specific saline aversions was exhibited by PN48 and PN64 rats, while the adult typical temporal context specificity of latent inhibition was only evident in PN100 rats. The results...

Dopamine's role in social modulation of infant isolation-induced vocalization: I. reunion responses to the dam, but not littermates, are dopamine dependent

Developmental Psychobiology — Thu, 13 Nov 2008 05:00:00 +0100

Rat pups' vocalization during social separation and the cessation of vocalization upon social reunion (contact quieting) model early life affiliative relationships. The present study examined the roles of dopamine (DA) receptors in regulating contact quieting. Contact quieting to the dam, but not to littermates, was disrupted by either blockade or exogenous stimulation of DA D1-like receptors. The D2 antagonist raclopride also prevented the quieting effect of reunion with the dam and had a lesser effect on the quieting properties of littermates. In contrast, the D2 agonist quinpirole permitted or enhanced contact quieting. Combined systemic and local striatal administration of D2 ligands showed that stimulation of striatal D2 receptors can enhance, but is not necessary for, contact quietin...

Larger tonic pupil size in young children with autism spectrum disorder

Developmental Psychobiology — Fri, 07 Nov 2008 05:00:00 +0100

The symptoms of Autism Spectrum Disorder (ASD) have been suggested to manifest from atypical functioning of the autonomic nervous system (ANS), leading to altered arousal and atypical processing of salient stimuli. Coherent with this, persons with ASD show heightened autonomic activity, sleep difficulties, and structural and neurochemical alterations within the ANS. Recently, we observed decreased pupil responses to human faces in children with ASD. In the current study, we found differences in baseline (tonic) pupil size, with the ASD group exhibiting a larger pupil size than age-matched controls. Pupil responses are sensitive and reliable measures of ANS functioning, thus, this finding highlights the role of the ANS, and may provide clues about underlying neuropathology. © 2008 Wiley Pe...

Prenatal behavior of the C57BL/6J mouse: A promising model for human fetal movement during early to mid-gestation

Developmental Psychobiology — Tue, 04 Nov 2008 05:00:00 +0100

In this study, we observed prenatal behavioral patterns of the C57BL/6J mouse, a common background strain for genetically altered mice, and report their similarity to those observed in the early to mid-gestation human fetus. Fetal offspring from pregnant C57BL/6J dams were observed on the day before birth (E18 of a 19-day gestation). Scoring and analysis of fetal movement included Prechtl's Method for Qualitative Assessment, Interlimb Movement Synchrony, a measure of the temporal relationship between movements of limb pairs, and Behavioral State, quantified through detailed analysis of high and low amplitude limb movements. With the exception of fetal breathing movements, all categories and patterns of behavior typically reported in the early to mid-gestation human fetus were observed in t...

Fetal size in mid- and late pregnancy is related to infant alertness: The generation R study

Developmental Psychobiology — Fri, 31 Oct 2008 04:00:00 +0100

The vulnerability for behavioral problems is partly shaped in fetal life. Numerous studies have related indicators of intrauterine growth, for example, birth weight and body size, to behavioral development. We investigated whether fetal size in mid- and late pregnancy is related to infant irritability and alertness. In a population-based birth cohort of 4,255 singleton full-term infants ultrasound measurements of fetal head and abdominal circumference in mid- and late pregnancy were performed. Infant irritability and alertness scores were obtained by the Mother and Baby Scales at 3 months and z-standardized. Multiple linear regression analyses revealed curvilinear associations (inverted J-shape) of measures of fetal size in both mid- and late pregnancy with infant alertness. Fetal size cha...

Using developmental cognitive neuroscience to study behavioral and attentional control

Developmental Psychobiology — Thu, 30 Oct 2008 04:00:00 +0100

Adult cognitive neuroscience employs a wide variety of techniques to investigate a broad range of behavioral and cognitive functions. One prominent area of study is that of executive control, complemented by a smaller but growing literature exploring the developmental cognitive neuroscience of executive control. To date this approach has often compared children with specific developmental disorders, such as ADHD and ASD, with typically developing controls. Whilst these comparisons have done much to advance our understanding of the neural markers that underpin behavioral difficulties at specific time-points in development, we contend that they should leave developmental cognitive neuroscientists wanting. Studying the neural correlates of typical changes in executive control in their own rig...

Maternal care can rapidly induce an odor-guided huddling preference in rat pups

Developmental Psychobiology — Wed, 22 Oct 2008 04:00:00 +0100

Olfactory-guided huddling is learned and expressed by postnatal day (PND) 15, when rat pups huddle preferentially with conspecifics or with targets bearing an odor previously associated with maternal care. Experiment 1 replicated this induction of an odor-guided huddling preference with a truncated regime of conditioning with a scented foster dam. Pups exposed to an odor in association with foster maternal care during five daily 2-hr sessions on PNDs 1-5, 5-9, or 10-14, but not pups merely exposed to the odor, displayed a huddling preference for the conditioned odor, but only when conditioning commenced after PND5. Experiment 2 demonstrated that a single, 2-hr exposure to a scented foster dam can induce a huddling preference in pups. Analysis of maternal behavior during the 2-hr conditioni...

Effects of siblings on reproductive maturation and infanticidal behavior in cooperatively breeding Mongolian gerbils

Developmental Psychobiology — Tue, 21 Oct 2008 04:00:00 +0100

Mongolian gerbils living with their natal families undergo delayed reproductive maturation while helping to rear their younger siblings, whereas those housed away from their natal families may mature earlier but often respond aggressively to unfamiliar pups. We tested whether cohabitation with pups contributes to reproductive suppression and inhibition of infanticidal behavior, using young males and females housed with (1) their parents and younger siblings (pups), (2) parents without pups, (3) mixed-sex littermate groups, or (4) mixed-sex groups of unrelated peers. Maturation in males was inhibited by cohabitation with the parents, while maturation in females was further suppressed in the presence of pups. Males in all housing conditions showed little aggression towards unfamiliar pups, w...

The influence of natural variations in maternal care on play fighting in the rat

Developmental Psychobiology — Wed, 08 Oct 2008 04:00:00 +0100

This study examined play fighting in the juvenile offspring of high-LG and low-LG dams in a multiple-play partners housing environment. Male offspring from low-LG dams demonstrated a significantly higher frequency of pouncing, pinning and aggressive social grooming than did high-LG males and high-LG and low-LG females. Consistent with earlier reports, male pups engaged in more play fighting than did females and maternal care was associated with differences in play fighting but only in males. Lower levels of stimulation in the form of LG from the dam during perinatal development may thus increase sensitivity for the stimulating effects of play behavior in periadolescence, in part explaining the increased solicitation of play fighting through increased pouncing in the male offspring of the l...

Effect of methamphetamine exposure and cross-fostering on sensorimotor development of male and female rat pups

Developmental Psychobiology — Tue, 07 Oct 2008 04:00:00 +0100

The present study tested the hypothesis that cross-fostering influences the development of rat pups. Mothers were exposed daily to injection of methamphetamine (M) (5 mg/kg) or saline for 9 weeks: 3 weeks prior to impregnation, throughout gestation and lactation periods. Control females animals without any injections were used. On postnatal day (PD) 1, pups were cross-fostered so that each mother received four pups of her own and eight pups from the mothers with the other two treatments. Offspring were tested for sensorimotor development in preweaning period by using tests of: negative geotaxis, tail pull, righting reflexes, rotarod and bar-holding. Further, the pups were weighed daily. Our results showed that birth weight in prenatally M-exposed pups was lower than in control or saline-ex...

Abstracts: International Society for Developmental Psychobiology, 41st Annual Meeting, November 12-15, 2008 Washington D.C.

Developmental Psychobiology — Fri, 26 Sep 2008 04:00:00 +0100

No Abstract. (Source: Developmental Psychobiology)

The effects of selective breeding for differential rates of 50-kHz ultrasonic vocalizations on emotional behavior in rats

Developmental Psychobiology — Thu, 25 Sep 2008 04:00:00 +0100

In this study, rats selectively bred for high and low rates of 50-kHz vocalizations as juveniles were tested as adults in a battery of behavioral tests for social/emotional behaviors. We found that animals selectively bred for high rates of 50-kHz vocalizations exhibited more crosses into the center area of the open field apparatus, were more likely to show a preference for a dilute sucrose solution (.8%) compared to tap water, and were less aggressive than randomly bred animals. Conversely, animals bred for low rates of 50-kHz calls produced more fecal boli during both open field testing and "tickling" stimulation, and made less contact with conspecifics in a social interaction test compared to randomly bred animals. We also observed that low line rats have elevated brain levels of cholec...

Predicting cardiac vagal regulation in early childhood from maternal-child relationship quality during toddlerhood

Developmental Psychobiology — Tue, 23 Sep 2008 04:00:00 +0100

The aim of this study was to examine the influence of maternal-child relationship quality during toddlerhood on early childhood physiological regulation. A community sample of 447 children (215 males) was recruited at age 2 for participation in the study using the Child Behavior Checklist [Achenbach [1992] Manual for the child behavior checklist/2-3 & 1992 profile. Burlington, VT: University of VT Department of Psychiatry]. Mothers and children were observed across several interactions in the laboratory at age 2 and mothers completed the Parenting Stress Index [Abidin [1995] Manual for the parenting stress index. Odessa, FL: Psychological Assessment Resources]. Relationship quality was assessed using laboratory measures of hostility, positive guidance, and stress related to the quality of ...

Iron deficiency anemia and affective response in rhesus monkey infants

Developmental Psychobiology — Mon, 22 Sep 2008 04:00:00 +0100

Infant iron deficiency anemia (IDA) occurs spontaneously in monkey populations as it does in humans, providing a model for understanding effects on brain and behavior. A set of 34 monkey infants identified as IDA (hemoglobin 12 g/dl) matched for age and caging location. The infants had participated in a Biobehavioral Assessment conducted at 3-4 months of age at CNPRC that included measures of behavioral and adrenocortical response to a novel environment. IDA males differed from control males in two factors ("activity," "emotionality") derived from observational data taken on the first and second day of the exposure to the novel environment. In the male infants, IDA was associated with less restriction of activity in the novel environment on both days and less emotionality on the second day...

In memory of Dr. Victor H. Denenberg

Developmental Psychobiology — Thu, 18 Sep 2008 04:00:00 +0100

No Abstract. (Source: Developmental Psychobiology)

To spear or not to spear: Comparison of saliva collection methods

Developmental Psychobiology — Tue, 02 Sep 2008 04:00:00 +0100

This study revealed that the degree of interference varied as a function of the specific type of eye spear that was employed; stimulant use had no effect. Taken together, the results raise important considerations to take into account when selecting collection materials and procedures in the measurement of salivary cortisol. © 2008 Wiley Periodicals, Inc. Dev Psychobiol (Source: Developmental Psychobiology)

Altered morphology of motor cortex neurons in the VPA rat model of autism

Developmental Psychobiology — Tue, 02 Sep 2008 04:00:00 +0100

Autism occurs in 1 in 1,000 children and incidence may be increasing. Investigating brain development and developmental injury in humans is difficult. As such, many studies rely on animal models of disorders. We chose to investigate the valproic acid-exposed rat, as this model shares many similarities with autism. Pregnant Long-Evans rats were administered either valproic acid (VPA) or saline during fetal neural tube development. Morphological analyses of cells in layer II of the golgi impregnated motor cortex were done to determine dendritic length, volume, and complexity in both groups. No differences were found in length or volume of cortical dendrites, but dendritic arborization was more complex in apical dendrites of pyramidal cells in VPA-exposed animals than controls. The implicatio...

The progesterone receptor and parental behavior in juvenile rats

Developmental Psychobiology — Wed, 06 Aug 2008 09:31:14 +0100

Juvenile rats exhibit enhanced parental behavior responses to foster pups from 18 to 25 days of age, compared to virgin adults. Previous studies in adult rats and mice suggest that progesterone can inhibit the display of parental care towards offspring. The present study investigated the role of progesterone in juvenile rat parental behavior. It is hypothesized that the decrease in parental responsiveness as juveniles age is due a progesterone-dependent inhibitory mechanism. Groups of male and female juveniles were subcutaneously implanted with the progesterone antagonist RU486, progesterone, or control implants. All juveniles were then tested for parental behaviors. No significant effects of either RU486 or progesterone treatments on parental behavior latencies were detected in male or fe...

A procedure for the measurement of infant skin conductance and its initial validation using clap induced startle

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

Studies examining psychophysiologic markers of infant emotional development abound. However, few studies have used skin conductance (SC), though it measure's sympathetic activity, and none have measured SC on infants sitting up and actively engaged with another person, a significant challenge given the measures sensitivity to movement artifact. In this pilot/feasibility study, we present a procedure for measuring infant SC during active engagement with another person who executes a series of startling claps to elicit an SC response. We measured SC on the plantar surface of the foot of seventeen 5-month-old infants. We found unconditioned SC responses that were related to the intensity of physical startle reactions for each clap trial. We also found anticipatory, conditioned SC responses th...

Electrodermal reactivity during the Trier Social Stress Test for children: Interaction between the serotonin transporter polymorphism and children's attachment representation

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

This study explores the relation between variations in the serotonin transporter gene (5-HTTLPR; long vs. short allele), the child's attachment representation (assessed with the Attachment Story Completion Task, reflecting the security of the parent-child relationship), and electrodermal reactivity during a public speaking task, the Trier Social Stress Test for Children (TSST-C) in a sample of 92 7-year-old. Electrodermal reactivity during the TSST-C was not directly associated with variations in 5-HTT. However, there was a significant gene-environment interaction effect of 5-HTT and attachment security on electrodermal reactivity. Results are interpreted in terms of cumulative protection: Children with a secure attachment representation as well as long 5-HTT alleles appeared to be less st...

Postnatal lead effects on the development of visual spatial acuity in rhesus monkeys (Macaca Mulatta)

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

This study compared the development of photopic spatial acuity in rhesus monkeys exposed to lead (n = 43) with monkeys (n = 23) not exposed to lead. Lead exposure began at Day 8 postpartum and continued daily throughout the first 26 weeks of postnatal life achieving target blood lead levels of 35-40 µg/dl by about 15 weeks. Photopic spatial acuity was evaluated by a preferential looking technique used clinically to assess spatial acuity in human infants. Acuity increased rapidly over the first few postnatal weeks achieving the maximum acuity level assessed (26.3 c/deg) by 7 weeks of age for most monkeys. Postnatal lead exposure at the dosages and durations studied did not affect the development of photopic spatial acuity. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 608-614, 2008. (...

The impact of stimulus type and early motherhood on attentional processing

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

The present study evaluated the impact of stimulus type and early motherhood on attentional processing. Auditory ERPs were recorded with a modified novelty oddball paradigm both in mothers who had recently given birth and in control women who were not in the state of early motherhood. Conventional tone pips were used as standards and deviants, and an infant cry served as an experimental stimulus of novelty value. Differences were revealed in the N100 amplitudes between the study groups with higher amplitudes in the mothers. A few days after childbirth the mothers seemed to be in a stage with an increased level of alertness and different types of surrounding stimuli may elicit a stronger arousal response than normally, not just those directly related to the new baby. The gating and the mech...

Neuroendocrine dysregulation following early social deprivation in children

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

Human and nonhuman animal studies reveal that early experiences with caregivers shape children's ability to regulate their responses to stress. To understand the effects of early deprivation on the regulation of the hypothalamic-pituitary-adrenal axis following social interactions, we examined urinary cortisol levels in a group of internationally adopted children who had experienced institutional care, and thus, species-atypical attachment relationships, early in life prior to adoption. Cortisol regulation was assessed both basally and following standardized interpersonal interactions between the child and his/her mother and the child and an unfamiliar adult. Postinstitutionalized children showed prolonged elevations in cortisol levels following the mother, but not the stranger, interactio...

Influence of prenatal psychosocial stress on cytokine production in adult women

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

The aim of the present study was to determine the association between prenatal stress and immune function in human adults. Peripheral blood mononuclear cells (PBMCs) from 34 healthy young women whose mothers experienced major negative life events during their pregnancy (Prenatal Stress, PS group, mean age 25, SD ± 4.34 years), and from a female comparison group (n = 28, CG, mean age 24 ± 3.40 years), were stimulated with phytohemagglutinin (PHA), and subsequent cytokine production was measured. A bias for T-helper 2 (Th2) cytokine production due to an overproduction of IL-4 relative to IFN-[gamma] after PHA stimulation was observed in PS subjects. In addition, IL-6 and IL-10 were also significantly elevated. To the best of our knowledge, this study is the first to suggest a direct associ...

Using drinking in the dark to model prenatal binge-like exposure to ethanol in C57BL/6J mice

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

Animal models of prenatal ethanol exposure are necessary to more fully understand the effects of ethanol on the developing embryo/fetus. However, most models employ procedures that may produce additional maternal stress beyond that produced by ethanol alone. We employed a daily limited-access ethanol intake model called Drinking in the Dark (DID) to assess the effects of voluntary maternal binge-like ethanol intake on the developing mouse. Evidence suggests that binge exposure may be particularly harmful to the embryo/fetus, perhaps due to the relatively higher blood ethanol concentrations achieved. Pregnant females had mean daily ethanol intakes ranging from 4.2 to 6.4 g/kg ethanol over gestation, producing blood ethanol concentrations ranging from 115 to 182 mg/dL. This level of ethanol ...

Olfactory learning in the rat neonate soon after birth

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

The first hours of a newborn rat's life entail locating and attaching to the mother's nipple not only for nutrition but also for protection and warmth. The present study sought to characterize olfactory learning in the rat neonate immediately after birth. Newborn rats were exposed to an odor at various time periods soon after birth and tested for behavioral activation and attachment to a surrogate nipple in the presence of this odor at 4-5 hr postpartum. Regardless of when pups were presented the odor (0, 1, or 2 hr after birth) motor activity was greater among pups previously exposed to the odor than pups with no odor experience. Similarly, latency to attach to the nipple in the presence of the odor was lower among odor-preexposed pups, especially when odor exposure began within an hour o...

Olfactory preference for own mother and litter in 1-day-old rabbits and its impairment by thermotaxis

Developmental Psychobiology — Tue, 05 Aug 2008 04:00:00 +0100

In conclusion, pups can recognize olfactory cues emanating from their mother and their siblings the day after birth. The preference for nesting materials would reflect in major part the combined attraction to maternal and sibling odors present in the nest. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 542-553, 2008. (Source: Developmental Psychobiology)

In memoriam: Seymour (Gig) Levine (January 23, 1925-October 31, 2007) he enabled us to see farther

Developmental Psychobiology — Thu, 12 Jun 2008 21:13:27 +0100

No Abstract. (Source: Developmental Psychobiology)

Fetal sensory-elicited body movements differ in breech compared to cephalic position

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

Behavior was examined in 28 near term fetuses in the breech versus cephalic position. Breech fetuses had fewer body movements to a vibroacoustic stimulus and more to an airborne sound. These findings raise the possibility of differential perceptual experience before birth. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 530-534, 2008. (Source: Developmental Psychobiology)

Relation of stable hand-use preferences to the development of skill for managing multiple objects from 7 to 13 months of age

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

Expression of multiple object management skills (manual acquisition and storage of objects) was examined longitudinally at 7, 9, 11, and 13 months for 38 infants (19 females) whose hand use preference was either stable (consistently right or left across the ages) or nonstable (either no hand-use preference exhibited or inconsistent preference across the ages). Four separate sets of four distinctive objects each were presented singly to the infant's right and left side, with the presentation of each subsequent object contingent on the infant manipulating the previous object. Expression of multiple object management skills significantly increased with age. Infants with stable hand-use preferences produced more object acquisition and storage acts than those without a stable hand-use preferenc...

From the reaching behavior at 5 months of age to hand preference at preschool age

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

The aim of the study was to examine the reaching behavior at the age of 5 months, and to determine whether and to what extent there is a relationship between hand use at this age and manual laterality at preschool age. 20 participants (13 girls and 7 boys) were investigated on two occasions: At the age of 5 months we assessed the hand use for reaching for four different objects placed at the infant's body midline or in their right or left hemispaces, respectively. At the age of 5 years and 7 months, we assessed the hand use for 22 motor tasks. The handedness status was calculated in order to reflect the sinistrality-dextrality continuum. All but one infant were unimanual reachers at 5 months of age. Preferential reaching was space dependent rather than object dependent at this stage. Child...

Age-related complexity and coupling of children's sitting posture

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

This study tested the hypothesis that postural complexity increases as the coupling across the axes of motion decreases as children get older. Children aged 6 and 10 years and young adults (18-23 years) were seated on a wooden box placed atop a force platform that recorded their mediolateral and anteroposterior center of pressure (COP) motion with their feet supported and unsupported. The COP path length and complexity decreased with age, and this was paralleled by an increase in relative phase entropy across the axes of sway motion. The postural sway of the younger children was dominated by slower fluctuations that were more tightly coupled across the axes of motion than the adults. The findings support the postulation that the development of children's sitting posture is characterized by...

The specificity of priming effects over the first year of life

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

This study determined the impact of cue and context changes on the initial priming and retrieval of the reactivated memory over the first postnatal year. Infants were operantly trained with a distinctive cue in a particular context. After forgetting, they were primed and tested for renewed retention with combinations of old and new cues and contexts. Priming was hyperspecific to the original cue and original context at all but 12 months, when the memory was reactivated in a novel context. At 9-12 months, the reactivated memory generalized to a novel cue or context. At younger ages, the reactivated memory generalized only after a very brief prime. These findings indicate that priming in early infancy is initially conservative, buffering against recovering memories in contexts that might no ...

A mouse model of fragile X syndrome exhibits heightened arousal and/or emotion following errors or reversal of contingencies

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

This study was designed to further assess cognitive and affective functioning in a mouse model of Fragile X syndrome (FXS), the Fmr1tm1Cgr or Fmr1 "knockout" (KO) mouse. Male KO mice and wild-type littermate controls were tested on learning set and reversal learning tasks. The KO mice were not impaired in associative learning, transfer of learning, or reversal learning, based on measures of learning rate. Analyses of videotapes of the reversal learning task revealed that both groups of mice exhibited higher levels of activity and wall-climbing during the initial sessions of the task than during the final sessions, a pattern also seen for trials following an error relative to those following a correct response. Notably, the increase in both behavioral measures seen early in the task was sig...

Stimulus contingency and the malleability of species-typical auditory preferences in Northern bobwhite (Colinus virginianus) hatchlings

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

Precocial avian hatchlings are typically highly social and show strong species-typical preferences for the maternal calls of their own species. The influence of social contingencies on the acquisition of species-specific preferences has, however, largely been neglected. We found that exposing bobwhite (BW) quail chicks to a Japanese quail (JQ) call contingent on their own vocalizations for 5 min was sufficient to eliminate their species-typical preference for the BW maternal call. Yoked, noncontingent exposure had no such effect. The introduction of variability to the contingency, but not a lengthening of the training session, was found to engender even higher preferences for the JQ call. Chicks provided with contingent exposure to the JQ call on a variable ratio schedule showed a signific...

Chronic social stress in adolescence influenced both amphetamine conditioned place preference and locomotor sensitization

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

We previously reported that chronic social stress (SS) in adolescence, but not in adulthood, increased the locomotor-activating effects of nicotine in females, and not males, when tested in adulthood. However, SS rats had decreased locomotor response to nicotine when tested in adolescence. Here, we investigated age-related changes in the effects of SS on both conditioned place preference (CPP) and locomotor sensitization to amphetamine. In the CPP experiment, SS females tested in adolescence had increased preference for the 1.0 mg/kg dose of amphetamine, whereas SS rats of both sexes showed a decrease in CPP for the 0.5 mg/kg dose when tested as adults. Irrespective of time of testing, SS males and females had enhanced locomotor sensitization compared to controls. Thus, adolescent SS produ...

Cortisol and externalizing behavior in children and adolescents: Mixed meta-analytic evidence for the inverse relation of basal cortisol and cortisol reactivity with externalizing behavior

Developmental Psychobiology — Thu, 12 Jun 2008 04:00:00 +0100

An inverse relation between cortisol (re)activity and externalizing behavior has been hypothesized, but research findings seem equivocal. We tested this hypo(re)activity hypothesis in two meta-analyses, one for basal cortisol (k = 72 studies, N = 5,480) and one for cortisol reactivity to a stressor (k = 29 studies, N = 2,601). No association was found between cortisol reactivity and externalizing behaviors (r = -.04, 95% CI = -.11, .02). However, the relation between basal cortisol and externalizing behavior was significant but small (r = -.05, 95% CI = -.10, -.002). The age of the children significantly moderated this relation: Externalizing behavior was associated with higher basal cortisol (hyperactivity) in preschoolers (r = .09, 95% CI = .002, .17), and with lower basal cortisol (hypo...

Effects of early deprivation and maternal separation on pup-directed behavior and HPA axis measures in the juvenile female rat

Developmental Psychobiology — Sat, 05 Apr 2008 13:09:28 +0100

Juvenile female rats show maternal-like behavior toward pups. The purpose of the following experiment was to investigate whether the HPA axis, through the use of early separation manipulations that alter HPA functioning in rats, plays a role in the juvenile response to foster pups. Female rats were early deprived or maternally separated for 5 hours daily from PND 2 to 14 and compared to animal facility-reared rats. Deprivation or separation increased CRH-R1 IR in the juvenile PVN, but had no other effects on other HPA measures or on maternal behavior. Pup-exposure during the juvenile period blunted corticosterone levels after acute and repeated pup-exposures when compared to exposure to novelty and conspecifics respectively. Repeated exposures to pups also increased CRH-R1 IR relative to i...

Surrogate mobility and orientation affect the early neurobehavioral development of infant rhesus macaques (Macaca mulatta)