Showing papers in "Developmental Psychobiology in 2010"
TL;DR: 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.
Abstract: 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. Heightened vulnerability to risk-taking in middle adolescence may be due to the combination of relatively higher inclinations to seek rewards and still maturing capacities for self-control.
825 citations
TL;DR: Most patients who have experienced early traumatic experiences are likely best treated with a combination of psychotherapy and pharmacotherapy, and the few current treatment outcome studies relevant to this research area are described.
Abstract: The effects of early-life trauma and its consequences for the treatment of depression are reviewed. The prevalence and clinical sequelae of early sexual and physical abuse, neglect and parental loss are described. An overview of preclinical studies that help guide clinical research and practice is presented. Human clinical studies on the neurobiological consequences of early trauma are summarized. Moderating factors, such as genetic variation and sex differences, are discussed. The few current treatment outcome studies relevant to this research area are described. Guidance for the management of patients with depression and a history of child abuse and neglect are provided. Most patients who have experienced early traumatic experiences are likely best treated with a combination of psychotherapy and pharmacotherapy. This review is dedicated to the memory of Seymour Levine who pioneered the field of early experience research and to a considerable extent inspired the clinical studies described in this review.
554 citations
TL;DR: It is argued that lack of experience with novel adult behavior poses a much greater risk to adolescents than structural deficits in brain maturation and continued translational research will help to identify strategies that protect youth as they transition to adulthood.
Abstract: 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 lack of experience with novel adult behavior poses a much greater risk to adolescents than structural deficits in brain maturation. Continued translational research will help to identify strategies that protect youth as they transition to adulthood.
505 citations
TL;DR: A neurobiological model of adolescence is provided that proposes an imbalance in the development of subcortical limbic regions relative to prefrontal cortical regions as a potential mechanism for heightened emotionality during this period.
Abstract: 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 imbalances in amygdala-ventrofrontal function increasing risk for anxiety related behaviors. Finally we present data from human and mouse studies to illustrate how genetic factors may enhance or diminish this risk. Together, these studies provide a converging methods approach for understanding the highly variable stress and turmoil experienced in adolescence.
395 citations
TL;DR: The purpose of this review is to discuss the recent findings regarding the pubertal maturation of stress reactivity, while also highlighting future research directions that will aid in the understanding of stress and adolescent mental health and development.
Abstract: 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 pubertal organisms react differentially, both physiologically and behaviorally, to a stressor compared to adults. The purpose of this review, therefore, is to discuss the recent findings regarding the pubertal maturation of stress reactivity, while also highlighting future research directions that will aid in our understanding of stress and adolescent mental health and development. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 244–253, 2010
280 citations
TL;DR: In this review, recent studies which highlight the epigenetic effects of parent-offspring, peer and adult social interactions both with and across generations will be discussed and the implications of this research for understanding the developmental origins of individual differences in brain and behavior will be explored.
Abstract: 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 parent-offspring, peer and adult social interactions both with and across generations will be discussed and the implications of this research for understanding the developmental origins of individual differences in brain and behavior will be explored.
247 citations
TL;DR: Results from ongoing studies of a similar process in squirrel monkeys suggest that brief intermittent exposure to stress promotes the development of arousal regulation and resilience.
Abstract: 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.
147 citations
TL;DR: Findings implicate vagal tone withdrawal as a psychophysiological measure of higher cognitive processes, most likely substantiated through increases in the levels of focused attention.
Abstract: Vagal tone (measured via respiratory sinus arrhythmia, RSA) and vagal withdrawal (measured by decreases in RSA) have been identified as physiological measures of self-regulation, but little is known how they may relate to the regulation of cognitive activity as measured through executive function (EF) tasks. We expected that baseline measures of vagal tone, thought to be an indicator of attention, would correlate with EF performance. We also predicted that vagal withdrawal would allow for the reorientation of attention that is needed to succeed on EF tasks, but too much withdrawal would be detrimental. RSA measured at baseline was indeed related to EF performance in 220 3.5-year-old children, and those who exhibited a moderate decrease in RSA during the EF tasks outperformed children whose RSA decreased by too little or too much. These findings implicate vagal tone withdrawal as a psychophysiological measure of higher cognitive processes, most likely substantiated through increases in the levels of focused attention.
146 citations
TL;DR: Insecure-resistant infants showed the largest increase in cortisol levels from pre- to post-SSP; the effect was even stronger when they had depressive mothers, and organized children showed a more flattened diurnal cortisol pattern compared to nondisorganized children.
Abstract: Both attachment insecurity and maternal depression are thought to affect infants' emotional and physiological regulation. In the current study, Strange Situation Procedure (SSP) attachment classifications, and cortisol stress reactivity and diurnal rhythm were assessed at 14 months in a prospective cohort study of 369 mother-infant dyads. Maternal lifetime depression was diagnosed prenatally using the Composite International Diagnostic Interview (CIDI). Insecure-resistant infants showed the largest increase in cortisol levels from pre-to post-SSP; the effect was even stronger when they had depressive mothers. Disorganized children showed a more flattened diurnal cortisol pattern compared to nondisorganized children. Findings are discussed from the perspective of a cumulative risk model.
129 citations
TL;DR: 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.
Abstract: 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 perhaps an increased probability for the emergence of abuse disorders. A number of potential (albeit tentative) implications of these basic research findings for prevention science are considered.
120 citations
TL;DR: Data indicate that functional changes in infant learning are modified by a unique interaction between the developing CORT system, the amygdala, and maternal presence, providing a learning system that becomes more flexible as pups mature.
Abstract: Here we review the neurobiology of infant odor learning in rats, and discuss the unique role of the stress hormone corticosterone (CORT) in the learning necessary for the developing rat. During the first 9 postnatal (PN) days, infants readily learn odor preferences, while aversion and fear learning are attenuated. Such restricted learning may ensure that pups only approach their mother. This sensitive period of preference learning overlaps with the stress hyporesponsive period (SHRP, PN4-14) when pups have a reduced CORT response to most stressors. Neural underpinnings responsible for sensitive-period learning include increased activity within the olfactory bulb and piriform "olfactory" cortex due to heightened release of norepinephrine from the locus coeruleus. After PN10 and with the decline of the SHRP, stress-induced CORT release permits amygdala activation and facilitates learned odor aversions and fear. Remarkably, odor preference and attenuated fear learning can be reestablished in PN10-15 pups if the mother is present, an effect due to her ability to suppress pups' CORT and amygdala activity. Together, these data indicate that functional changes in infant learning are modified by a unique interaction between the developing CORT system, the amygdala, and maternal presence, providing a learning system that becomes more flexible as pups mature.
TL;DR: Investigating the effects of early caregiving on markers of biobehavioral development at ages 2 and 3 years in humans demonstrates that ordinary variations in MCB influence stress reactivity and social behavior in young children.
Abstract: Rodent models of early caregiving find that pups reared by dams providing low levels of early stimulation subsequently display heightened stress reactivity and social aggression. We examined these effects in humans by investigating the effects of early caregiving on markers of biobehavioral develop- ment at ages 2 and 3 years. This study extended the findings reported by Hane and Fox (Hane and Fox (2006) Psychol. Sci. 17: 550-556) in which 185 mothers and infants were observed and scored for variations in maternal caregiving behavior (MCB) at age 9 months. Relative to young children who received high-quality MCB in infancy, those who received low-quality MCB showed significantly higher socially inhibited behavior with adults, right frontal electroencephalographam (EEG) asymmetry, aggressive play, and maternal reported internalizing behavior problems and anger proneness. These effects were independent of early temper- amental reactivity. Results parallel rodent models and demonstrate that ordinary variations in MCB influence stress reactivity and social behavior in young children. 2010 Wiley Periodicals, Inc. Dev Psychobiol
TL;DR: The response of both male and female adolescent, late adolescent, young adult, and older adult rats to three tests of anxiety-like behavior showed that adolescent rats exhibited a higher anxiety- like response than adults on each test.
Abstract: In human beings, susceptibility to anxiety disorders can be relatively high during adolescence. Understanding the ontogeny of anxiety-like behavior in laboratory rodents has implications for developing anxiolytic drugs that are suitable for this age group. Given the dearth of information about adolescent rodents, this study examined the response of both male and female adolescent, late adolescent, young adult, and older adult rats to three tests of anxiety-like behavior: the emergence test (ET), open field (OF), and elevated plus-maze (EPM). The results showed that adolescent rats exhibited a higher anxiety-like response than adults on each test; the amount of locomotion in the OF and percentage of time spent on the open arms of the EPM increased across the age groups, while older adult rats made the fewest start box re-entries in the ET. These results support the hypothesis that adolescent rats have a more pronounced response to stressors than do adults. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 731–739, 2010.
TL;DR: A new method for quantifying individual variability using dynamic measures of respiratory sinus arrhythmia incorporated temporal variation into the measurement of RSA and provided information beyond that offered by more traditional quantifications such as difference scores.
Abstract: In this study, we examined a new method for quantifying individual variability using dynamic measures of respiratory sinus arrhythmia (RSA). This method incorporated temporal variation into the measurement of RSA and provided information beyond that offered by more traditional quantifications such as difference scores. Dynamic and static measures of change in RSA were tested in relation to displays of emotion and affective behaviors during a fear-eliciting episode in a sample of 88 typically developing and high-fear toddlers during a laboratory visit at age 24 months. Dynamic measures of RSA contributed information that was unique from traditionally employed, static change scores in predicting high-fear toddlers' displays of shyness during a fear-eliciting episode. In contrast, RSA change scores offered information related to boldness in nonhigh-fear children. In addition, several associations included estimates of nonlinearchange in RSA. Implications for the study of individual differences in RSA and relations with emotion and emotion regulation are discussed. ! 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 372-382, 2010.
TL;DR: The results suggest that early visual experience is necessary to set up (or preserve) the neural architecture used for processing human faces, but not for processing objects in general.
Abstract: Early visual deprivation caused by bilateral congenital cataracts produces deficits in discriminating faces that differ in the spacing of features, but not in feature shape (Le Grand et al. (2001) Nature 410: 810). We investigated whether these deficits are specific to human faces by testing patients' ability to discriminate between stimuli differing only in feature spacing in human and monkey faces (Experiment 1) and in houses (Experiment 2). Patients, as a group, showed deficits on only one task: they had lower accuracy than normal in discriminating feature spacing in human faces. In contrast, they were normal in discriminating feature spacing in monkey faces and in houses. The results suggest that early visual experience is necessary to set up (or preserve) the neural architecture used for processing human faces, but not for processing objects in general. ! 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 775-781, 2010.
TL;DR: The biological, familial, and broader relationship contexts of puberty are considered along with unique contexts for early maturing girls versus boys and potential strategies for intervention based on these explanatory models are identified.
Abstract: 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.
TL;DR: Results from this longitudinal study indicated that children who exhibited right frontal asymmetry in early childhood experienced more physiological arousal during the speech task at age 9 and less ability to regulate their emotions as reported by their parents.
Abstract: 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 41=2 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 ability to regulate their emotions as reported by their parents. Findings are discussed in light of the associations between temperament and development of anxiety disorders. 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 197-204, 2010.
TL;DR: The nature and mechanisms of early-life experience-induced programming are discussed, focusing on work from the lab that was inspired by Seymour Levine and his fundamental contributions to the field.
Abstract: The concept that early-life experience influences the brain long-term has been extensively studied over the past 50 years, whereas genetic factors determine the sequence and levels of expression of specific neuronal genes, this genetic program can be modified enduringly as a result of experience taking place during critical developmental periods. This programming is of major importance because it appears to govern many behavioral and physiological phenotypes and promote susceptibility or resilience to disease. An established example of the consequences of early-life experience-induced programming includes the effects of maternal care, where patterns of augmented care result in decreased neuroendocrine stress responses, improved cognition and resilience to depression in the recipients of this care. Here, we discuss the nature and mechanisms of this programming phenomenon, focusing on work from our lab that was inspired by Seymour Levine and his fundamental contributions to the field.
TL;DR: Developmental limits for corticosterone regulation of pup learning are PN6 through PN15, and results suggest pups are protected from learning aversions to maternal odor until approaching weaning.
Abstract: Enhanced odor preference learning and attenuated fear learning characterizes rat pups' attachment learning Sensitive Period for learning the maternal odor. This period terminates at 10 days old (PN10) with increasing endogenous levels of the stress hormone, corticosterone. Increasing Sensitive Period pups' corticosterone prematurely terminates the Sensitive Period, while decreasing corticosterone in older pups delays Sensitive Period termination. Here we extend these findings and define the age range corticosterone alters learning and question whether corticosterone permanently terminates the Sensitive Period. Pups were odor-0.5 mA shock conditioned with either corticosterone increased (PN5-6; 4 mg/kg vs. saline) or decreased (PN15-16; naturally by maternal presence or corticosterone synthesis blocker, Metyrapone). Finally, PN7-8 pups were conditioned with corticosterone and reconditioned without corticosterone to assess whether the Sensitive Period was permanently terminated. Results indicate developmental limits for corticosterone regulation of pup learning are PN6 through PN15. Furthermore, inducing precocious corticosterone induced fear learning was not permanent, since reconditioning without corticosterone enabled odor preference learning. Results suggest pups are protected from learning aversions to maternal odor until approaching weaning.
TL;DR: 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 revealed that the experimental infants experienced significantly fewer episodes of feeding intolerance and achieved full enteral feeds quicker compared to the control group.
Abstract: 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 episodes of feeding intolerance and achieved full enteral feeds quicker compared to the control group. Further, in an analysis evaluating all three groups separately, it was noted that Group 1 experienced significantly fewer episodes of feeding intolerance compared to the control group. Study findings warrant further investigation of exposure to maternal voice and the developmental timing at which exposure is begun.
TL;DR: Findings highlight the need to focus on the early stability in physiological measures that may be implicated later in developing behavioral problems.
Abstract: Stability in frontal brain electrical activity (i.e., electroencephalographic or EEG) asymmetry at 10 and 24 months was examined with respect to maternal ratings of internalizing and externalizing behaviors at 30 months in a sample of 48 children. Children with stable left frontal EEG asymmetry during infancy were rated higher in externalizing behaviors by their mothers, whereas children with stable right frontal EEG asymmetry were rated higher in internalizing behaviors. These findings highlight the need to focus on the early stability in physiological measures that may be implicated later in developing behavioral problems.
TL;DR: It is found that maternal licking of the pups reduced stress responsiveness and inflammation in pups subjected to modest repeated pain during the first weeks of life and that it also blunted adult sensitivity to thermal pain.
Abstract: For half a century, Seymour Levine's pioneering work on the interactions between mother and infant have helped us understand the critical early factors that shape physiology and behavior in the adult offspring. The work from my laboratory described in this review was based on many experiments by Levine and coworkers demonstrating that the quantity and quality of maternal milk and of maternal-infant contact influence different aspects of the hypothalamus-pituitary-adrenal (HPA) activity in the neonate. We have extended this work by showing that maternal high-fat feeding during the prenatal and lactational period blunts stress responsiveness in neonatal pups, in part mediated by increased circulating leptin levels in the offspring. The blunting of stress responses during this specific neonatal period might be beneficial to prevent the negative effects of exaggerated glucocorticoid secretion on the developing brain. In line with Levine's previous work, we found that maternal licking of the pups reduced stress responsiveness and inflammation in pups subjected to modest repeated pain during the first weeks of life and that it also blunted adult sensitivity to thermal pain. These studies have important implications for human infants as mechanisms aimed at reducing stress responsiveness can be considered protective to the developing brain from exaggerated and untimely neuroendocrine and sympathetic stimulation. Non-invasive interventions targeted at maternal nutrition and maternal care are relatively easy to implement and might have a significant effect on the health outcome of the offspring, particularly in a vulnerable population of term and pre-term babies.
TL;DR: The empirical evidence from this study suggests that sustained parental efforts have a beneficial effect on reducing high-risk drinking and preventing harm even at this late stage of late adolescent/early adult development.
Abstract: 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. and focuses on examining: (1) the relationship between parenting and student drinking tendencies during the transitional period between high school and college and into the first year of college, and (2) the mediation process by which sustained parenting throughout the first year is related to college-drinking outcomes and consequences so as to inform future intervention efforts. The empirical evidence from this study suggests that sustained parental efforts have a beneficial effect on reducing high-risk drinking and preventing harm even at this late stage of late adolescent/early adult development.
TL;DR: There is converging evidence from several disciplines that environmental variations experienced by mothers and fathers may lead to plasticity in the development and behavior of offspring and that this phenotypic inheritance can be solely transmitted through the germline.
Abstract: Mothers and fathers do not contribute equally to the development of their offspring. In addition to the differential investment of mothers versus fathers in the rearing of offspring, there are also a number of germline factors that are transmitted unequally from one parent or the other that contribute significantly to offspring development. This article shall review four major sources of such parent-of-origin effects. Firstly, there is increasing evidence that genes inherited on the sex chromosomes including the nonpseudoautosomal part of the Y chromosome that is only inherited from fathers to sons, contribute to brain development and behavior independently of the organizing effects of sex hormones. Secondly, recent work has demonstrated that mitochondrial DNA that is primarily inherited only from mothers may play a much greater than anticipated role in neurobehavioral development. Thirdly, there exists a class of genes known as imprinted genes that are epigenetically silenced when passed on in a parent-of-origin specific manner and have been shown to regulate brain development and a variety of behaviors. Finally, there is converging evidence from several disciplines that environmental variations experienced by mothers and fathers may lead to plasticity in the development and behavior of offspring and that this phenotypic inheritance can be solely transmitted through the germline. Mechanistically, this may be achieved through altered programming within germ cells of the epigenetic status of particular genes such as retrotransposons and imprinted genes or potentially through altered expression of RNAs within gametes.
TL;DR: Although the each type of RDBM appears early in infancy, R DBM only begins to exhibit the characters of a skill by 13 months, and the type of toy influences not only the likelihood of eliciting role differentiation, but also the type-based behavior and the organization of the sequence of actions that lead to RDBm.
Abstract: 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 although the each type of RDBM appears early in infancy, RDBM only begins to exhibit the characters of a skill by 13 months. Moreover, the type of toy influences not only the likelihood of eliciting role differentiation, but also the type of RDBM behavior and the organization of the sequence of actions that lead to RDBM. Some useful criteria for defining an infant sensorimotor skill are provided in discussion. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:168–180, 2010
TL;DR: The current state of knowledge regarding the contribution of the epigenome toward the development of psychiatric disorders is reviewed.
Abstract: 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.
TL;DR: Examination of the concentration of mothers' peripherally produced oxytocin after close physical interactions with their biological and non-biological children found Oxytocin levels were higher among mothers following interactions with unfamiliar children than following interaction with their own children.
Abstract: The current study examined the concentration of mothers’ peripherally produced oxytocin after close physical interactions with their biological and non-biological children. Each of 35 mothers and children participated in a computer game that promoted physical contact. In one interaction context, mothers interacted with their own children, and in the other context, mothers interacted with unfamiliar children. After the activity, urine samples were collected from the mothers and were assayed for oxytocin. Data from 26 mothers were available for oxytocin analyses. Oxytocin levels were higher among mothers following interactions with unfamiliar children than following interactions with their own children. Possible explanations for the differences in oxytocin levels across contexts are discussed.
TL;DR: Across both experiments, amygdala-lesioned animals appeared to be less behaviorally inhibited insofar as they explored all objects most readily, and hippocampus-lesion animals' propensity for exploration mirrored that of control animals in some contexts but that of amygdala-LESioned animals in other contexts.
Abstract: Medial temporal lobe brain structures, such as the amygdala, play an important role in the normal perception and generation of emotional behavior. Little research, however, has assessed the role of such structures across the neurodevelopmental trajectory. We assessed emotional behavioral responses of rhesus macaques that received bilateral ibotenic acid lesions of the amygdala or hippocampus at 2 weeks of age and sham-operated controls. At 9 and 18 months of age, animals interacted with novel objects that varied in visual complexity as a means of varying emotional salience. All animals behaved differently in the presence of visually simple, as compared to complex, objects, suggesting that they were sensitive to variation in emotional salience. Across both experiments, amygdala-lesioned animals appeared to be less behaviorally inhibited insofar as they explored all objects most readily. Interestingly, hippocampus-lesioned animals' propensity for exploration mirrored that of control animals in some contexts but that of amygdala-lesioned animals in other contexts. At 18 months of age, both amygdala-lesioned and hippocampus-lesioned animals were judged to be less fearful than controls during the testing procedure. Implications for understanding the neurobiology of emotional behavior are discussed.
TL;DR: Ethanol intake during late adolescence was greatest in animals initiated to ethanol earliest at postnatal Day 28, and females that were more sensitive to ethanol's locomotor-activating effects showed a transient increase in ethanol self-administration.
Abstract: Adolescent initiation of ethanol consumption is associated with subsequent heightened probability of ethanol use disorders. The present study examined the relationship between motivational sensitivity to ethanol initiation in adolescent rats and later ethanol intake. Experiment 1 determined that ethanol induces locomotor activation shortly after administration but not if tested at a later post-administration interval. In Experiment 2, adolescent rats were assessed for ethanol-induced locomotor activation on postnatal Day 28. These animals were then evaluated for ethanol-mediated conditioned taste aversion and underwent a 16-day-long ethanol intake protocol. Ethanol-mediated aversive effects were unrelated to ethanol locomotor stimulation or subsequent ethanol consumption patterns. Ethanol intake during late adolescence was greatest in animals initiated to ethanol earliest at postnatal Day 28. Females that were more sensitive to ethanol's locomotor-activating effects showed a transient increase in ethanol self-administration. Blood ethanol concentrations during initiation were not related to ethanol-induced locomotor activation. Adolescent rats appeared sensitive to the locomotor-stimulatory effects of ethanol. Even brief ethanol exposure during adolescence may promote later ethanol intake.
TL;DR: Overall the film paradigm was applicable across a wide developmental span, revealing potential developmental and gender differences in baseline startle magnitude and response probability.
Abstract: A film paradigm was developed to examine baseline and emotion modulated startle across a broad age range from preschool to adulthood. The paradigm was tested in children (3-, 5-, 7-, and 9-year-olds) and adults (total N = 122). The paradigm elicited a similar startle potentiation pattern across age groups; however, baseline startle changed with age: 3- and 5-year-olds showed lower response probability and magnitude of baseline startle than adults. Females exhibited larger baseline startle response probability and overall magnitude than did males; however, no sex by emotion modulated startle interaction was noted. Anxiety measures were obtained for all children. Individual differences in anxiety were associated with baseline startle magnitude among older but not younger children. No association of anxiety with startle potentiation was noted. Overall the film paradigm was applicable across a wide developmental span, revealing potential developmental and gender differences in baseline startle magnitude and response probability.