Showing papers in "Developmental Psychobiology in 2013"
TL;DR: Amniotic fluid cortisol predicted infant cortisol response to separation-reunion stress: infants who were exposed to higher levels of cortisol in utero showed higher pre-stress cortisol values and blunted response to stress exposure.
Abstract: Experimental animal findings suggest that early stress and glucocorticoid exposure may program the function of the hypothalamic-pituitary-adrenal (HPA) axis in the offspring. The extension of these findings to human development is not yet clear. A prospective longitudinal study was conducted on 125 mothers and their normally developing children. Amniotic fluid was obtained at, on average, 17.2 weeks gestation; infant behavior and cortisol response to a separation-reunion stress was assessed at 17 months. Amniotic fluid cortisol predicted infant cortisol response to separation-reunion stress: infants who were exposed to higher levels of cortisol in utero showed higher pre-stress cortisol values and blunted response to stress exposure. The association was independent of prenatal, obstetric, and socioeconomic factors and child-parent attachment. The findings provide some of the strongest data in humans that HPA axis functioning in the child may be predicted from prenatal cortisol exposure.
151 citations
TL;DR: Similar to reports of typically developing children, ASD children with higher RSA amplitude at baseline showed greater RSA and HP reactivity during an attention-demanding task, highlighting the importance of studying RSA as a marker of positive function in children with ASD.
Abstract: The current study builds on the emerging autism spectrum disorder (ASD) literature that associates autonomic nervous system activity with social function, and examines the link between respiratory sinus arrhythmia (RSA) and both social behavior and cognitive function. The RSA response pattern was assessed in 23 4- to 7-year-old children diagnosed with an ASD. Higher baseline RSA amplitudes were associated with better social behavior (i.e., more conventional gestures, more instances of joint attention) and receptive language abilities. Similar to reports of typically developing children, ASD children with higher RSA amplitude at baseline showed greater RSA and HP reactivity during an attention-demanding task. These results highlight the importance of studying RSA as a marker of positive function in children with ASD.
135 citations
TL;DR: A marked change in the retention of episodic memories between 3 and 4 years of age suggests that it is the authors' ability to retain, rather than to form, an episodic memory that limits the ability to recall episodes from early childhood.
Abstract: Episodic memory endows us with the ability to reflect on our past and plan for our future. Most theorists argue that episodic memory emerges during the preschool period and that its emergence might herald the end of childhood amnesia. Here, we show that both 3- and 4-year-old children form episodic memories, but that 3-year-old children fail to retain those memories following a delay (Experiments 1 and 2). In contrast, 4-year-old children retained episodic memories over delays of 24 hr (Experiment 1) and 1 week (Experiment 3). This marked change in the retention of episodic memories between 3 and 4 years of age suggests that it is our ability to retain, rather than to form, an episodic memory that limits our ability to recall episodes from early childhood. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 55: 125–132, 2013
119 citations
TL;DR: How the data of hand preferences for bimanual coordinated actions highlight the role of ecological factors in the evolution of handedness and provide additional support the postural origin theory ofhandedness proposed by MacNeilage is discussed.
Abstract: Within the evolutionary framework about the origin of human handedness and hemispheric specialization for language, the question of expres- sion of population-level manual biases in nonhuman primates and their potential continuities with humans remains controversial. Nevertheless, there is a growing body of evidence showing consistent population-level handedness particularly for complex manual behaviors in both monkeys and apes. In the present article, within a large comparative approach among primates, we will review our contribution to the field and the handedness literature related to two particular sophisticated manual behaviors regarding their potential and specific implications for the origins of hemispheric specialization in humans: bimanual coordinated actions and gestural communication. Whereas bimanual coordinated actions seem to elicit predominance of left-handedness in arboreal primates and of right- handedness in terrestrial primates, all handedness studies that have investigated gestural communication in several primate species have reported stronger degree of population-level right-handedness compared to noncommunicative actions. Communicative gestures and bimanual actions seem to affect differently manual asymmetries in both human and nonhuman primates and to be related to different lateralized brain substrates. We will discuss (1) how the data of hand preferences for bimanual coordinated actions highlight the role of ecological factors in the evolution of handedness and provide additional support the postural origin theory of handedness proposed by MacNeilage (MacNeilage (2007). Present status of the postural origins theory. In W. D. Hopkins (Ed.), The evolution of hemispheric specialization in primates (pp. 59-91). London: Elsevier/Academic Press) and (2) the hypothesis that the emergence of gestural communication might have affected lateralization in our ancestor and may constitute the precursors of the hemispheric specialization for language. 2013 Wiley Periodicals, Inc. Dev Psychobiol 55: 637-650, 2013.
113 citations
TL;DR: Social stress in adolescence in male rats in adolescence increases open field anxiety while maintaining exploratory behavior, and alters social interactions in adulthood.
Abstract: We investigated the effects of social instability stress (daily 1-hr isolation, change of cage partner, postnatal day 30-45) in adolescence in male rats on open field exploration and social behavior in adulthood. Social stressed rats had longer latencies to enter the center of an open field and then took longer to approach an object placed in the center of the field. When another rat was placed in the open field, stressed rats spent less time in social interaction than control rats, particularly when paired with another stressed, rather than a control, rat. The groups did not differ in social approach tests (when a stimulus rat was separated by wire mesh) nor in novel object exploration (when controlling for open field anxiety). The results suggest social stress in adolescence increases open field anxiety while maintaining exploratory behavior, and alters social interactions in adulthood.
93 citations
TL;DR: The paper concludes that the initial developmental emergence of lateralized behavior is under genetic control and is a fundamental feature of prenatal human development and correlates with more efficient information processing as assessed by habituation.
Abstract: This paper reviews the evidence for lateralized motor behavior in the fetus around a number of key questions: does the fetus exhibit signs of laterality? when does lateralized motor behavior begin? is the lateralized preference consistently displayed? does prenatal handedness relate to postnatal handedness? and, does prenatal handedness relate to brain functioning? The evidence indicates that the fetus exhibits lateralized behavior from 10 weeks gestation, as soon as it independently moves its arms, and this is the precursor of lateralized motor behavior observed post-natally. Data is presented suggesting that the strength of laterality decreases with advancing gestation and this correlates with more efficient information processing as assessed by habituation. However extreme caution is warranted in attempting to link asymmetric motor behavior and brain function prenatally. The paper concludes that the initial developmental emergence of lateralized behavior is under genetic control and is a fundamental feature of prenatal human development. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 55: 588–595, 2013.
84 citations
TL;DR: Maternal positive affect and infant frontal brain electrical activity measured when the children were 10 months jointly and uniquely predicted both preschool and post-kindergarten EF.
Abstract: Little is known about factors that promote optimal development of executive function skills. The focus of this study was associations among early maternal behaviors, infant frontal brain electrical activity, and child executive functions at age four and following kindergarten. Infant frontal electroencephalogram was collected from 56 infants at 10 months of age and maternal positive affect was observed. Children completed executive function measures in the research laboratory at age four; parental-reported executive function was obtained following children’s kindergarten year. Maternal positive affect and infant frontal brain electrical activity measured when the children were 10 months jointly and uniquely predicted both preschool and post-kindergarten executive function. Findings suggest parenting behavior and brain development in infancy are precursors of later self-regulatory executive function abilities.
82 citations
TL;DR: The results demonstrate prenatal experience may affect behavior well into childhood, and that prenatal experience could influence behavior much later in life.
Abstract: The human fetus learns about its chemosensory environment and this influences its behavior at birth and during the nursing period. This study examined whether prenatal experience could influence behavior much later in life. The dietary preference of two groups of children (8- to 9-years old) was examined. Mothers of one group had consumed garlic during pregnancy, mothers of the control group had not. Children received two tests, 1 month apart, of a meal containing two portions of potato gratin, one flavored with garlic. The total amount of potato, and the percentage of garlic flavored potato, eaten was calculated and examined separately by ANOVA for factors of prenatal exposure, the child's sex, and trial. Children prenatally exposed to garlic ate significantly more garlic flavored potato and a significantly greater overall amount of potato on trial 2, compared to controls. The results demonstrate prenatal experience may affect behavior well into childhood.
78 citations
TL;DR: In this paper, the authors examined afternoon levels of salivary alpha-amylase (sAA) and cortisol (used to assess stress-based responses) in two independent samples of children with ASD.
Abstract: Dysregulated tonic pupil size has been reported in autism spectrum disorder (ASD). Among the possible sources of this dysregulation are disruptions in the feedback loop between norepinephrine (NE) and hypothalamic systems. In the current study, we examined afternoon levels of salivary alpha-amylase (sAA, a putative correlate of NE) and cortisol (used to assess stress-based responses) in two independent samples of children with ASD. We found a larger pupil size and lower sAA levels in ASD, compared to typical and clinical age-matched controls. This was substantiated at the individual level, as sAA levels were strongly correlated with tonic pupil size. Relatively little diurnal variation in sAA taken in the home environment in the ASD group was also observed, while typical controls showed a significant linear increase throughout the day. Results are discussed in terms of potential early biomarkers and the elucidation of underlying neural dysfunction in ASD.
72 citations
TL;DR: Compared with young and mature C57BL/6 mice that have been housed in circular or rectangular environments, rearing environments influenced the relative use of feature and geometric cues in a reorientation task as predicted by the adaptive combination approach.
Abstract: After becoming disoriented, organisms must re-establish their position in space. The core knowledge position argues that reorientation relies only on extended 3D surfaces, and that this sensitivity operates automatically and is innately present. In contrast, the adaptive combination perspective argues that reorientation is experience-expectant and malleable, and depends on both extended 3D surfaces and 2D feature cues. We test these divergent views by comparing young (Experiment 1) and mature (Experiment 2) C57BL/6 mice (Mus musculus) that have been housed in circular or rectangular environments. Malleability of feature cues was found for young mice. Malleability of incidental geometry coding was found for both age groups. The relative dependence on geometric and feature cues changed with age. Young mice weighted the feature cue more heavily than adult mice. In summary, as predicted by the adaptive combination approach, rearing environments influenced the relative use of feature and geometric cues in a reorientation task. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 243–255, 2013
64 citations
TL;DR: For example, this article found that both mothers and fathers had less sleep, more self-reported sleep disturbance, and higher ratings of fatigue during the first month postpartum when compared to their levels during the pregnancy period.
Abstract: The Centers for Disease Control and Prevention Statistics reported that across the last decade, there have been over four million childbirths each year in the United States (Martin et al., 2011). With the birth of each child, new parents are required to adjust to the demands of parenthood. Accordingly, sleep disturbance is commonly experienced among new parents during the early postpartum period, and sleep disturbance is known to have a multitude of adverse effects on health and functioning (see reviews: Alvarez & Ayas, 2004; Copinschi, 2005; Harrison & Horne, 2000).
Postpartum sleep disturbance is caused by factors that include infant signaling during nocturnal periods (Nishihara, Horiuchi, Eto, & Uchida, 2000; Nishihara, Horiuchi, Eto, & Uchida, 2001), maternal postpartum endocrine and physiological changes that affect sleep (Manber & Armitage, 1999; Santiago, Nolledo, Kinzler, & Santiago, 2001), and the sleep disturbances experienced by the other bed partner within the postpartum parent dyad (Meijer & vanden Wittenboer, 2007). Sleep within the family system can be interrupted by multiple factors, all of which result in sleep disturbance experienced by both mothers and fathers.
Maternal postpartum sleep profiles have been well described (see reviews: Ross, Murray, & Steiner, 2005; Hunter, Rychnovsky, & Yount, 2009). Maternal sleep worsens progressively throughout pregnancy and is most affected, primarily by sleep fragmentation immediately following delivery after which it improves steadily throughout the postpartum period (Shinkoda, Matsumoto, & Park, 1999; Kang, Matsumoto, Shinkoda, Mishima, & Seo, 2002; Rychnovsky & Hunter, 2009; Montgomery-Downs, Insana, Clegg-Kraynok, & Mancini, 2010). Paternal sleep profiles during the postpartum period have been less extensively profiled. Among the existing literature, there are reported changes in postpartum fathers’ sleep from the prenatal to the postpartum period (Condone, Boyce, & Corkindale, 2004). Gay and colleagues reported that both mothers and fathers had less sleep, more self-reported sleep disturbance, and higher ratings of fatigue during the first month postpartum when compared to their levels during the pregnancy period (Gay, Lee, & Lee, 2004).
Although postpartum maternal, and to a lesser extent, paternal sleep disturbances are recognized, to date no investigations have objectively quantified the extent of sleepiness, and functional impact of sleep disturbance experienced among postpartum mothers or fathers. The study objective was to fill this void through examination of sleep, sleepiness, fatigue, and neurobehavioral performance among healthy first-time mothers and fathers during their early postpartum period. All values were compared within postpartum couples, and between postpartum and childless control couples.
TL;DR: Evidence derived from across-species investigations of epigenetics, development, and plasticity are highlighted which may contribute to the understanding of the homology that exists between species and between ancestors and descendants.
Abstract: Plasticity is a typical feature of development and can lead to divergent phenotypes. There is increasing evidence that epigenetic mechanisms, such as DNA methylation, are present across species, are modifiable by the environment, and are involved in developmental plasticity. Thus, in the context of the concept of developmental homology, epigenetic mechanisms may serve to create a process homology between species by providing a common molecular pathway through which environmental experiences shape development, ultimately leading to phenotypic diversity. This article will highlight evidence derived from across-species investigations of epigenetics, development, and plasticity which may contribute to our understanding of the homology that exists between species and between ancestors and descendants.
TL;DR: Some of the methodological and statistical challenges to comparative studies of handedness in human and nonhuman primates are discussed and a framework for developing some consensus on evaluating the validity of different handedness measures and the characterization of individual hand preferences is offered.
Abstract: In the past 20–25 years, there have been a number of studies published on handedness in nonhuman primates. The goal of these studies has been to evaluate whether monkeys and apes show patterns of hand preference that resemble the right-handedness found in the human species. The extant findings on handedness in nonhuman primates have revealed inconsistent evidence for population-level handedness within and between species. In this article, I discuss some of the methodological and statistical challenges to comparative studies of handedness in human and nonhuman primates. I further offer a framework for developing some consensus on evaluating the validity of different handedness measures and the characterization of individual hand preferences.
TL;DR: Some of the empirical evidence for the importance of neural reuse-the reuse of existing (inherited and/or early developing) neural circuitry for multiple behavioral purposes-in defining the overall functional structure of the brain is laid out.
Abstract: This article lays out some of the empirical evidence for the impor- tance of neural reuse—the reuse of existing (inherited and/or early developing) neural circuitry for multiple behavioral purposes—in defining the overall functional structure of the brain. We then discuss in some detail one particular instance of such reuse: the involvement of a local neural circuit in finger aware- ness, number representation, and other diverse functions. Finally, we consider whether and how the notion of a developmental homology can help us understand the relationships between the cognitive functions that develop out of shared neu- ral supports. 2012 Wiley Periodicals, Inc. Dev Psychobiol
TL;DR: It is shown that a developmental cue, early maternal care, correlates with social learning propensities in adult rodents, raising the possibility that social learningpropensities may be both relatively stable throughout life and part of a suite of traits "adaptively programmed" by early developmental experiences.
Abstract: Many vertebrates rely extensively on social information, but the value of information produced by other individuals will vary across contexts and habitats. Social learning may thus be optimized by the use of developmental or current cues to determine its likely value. Here, we show that a developmental cue, early maternal care, correlates with social learning propensities in adult rodents. The maternal behavior of rats Rattus norvegicus with their litters was scored over the first 6 days postpartum. Rat dams show consistent individual differences in the rate they lick and groom (LG) pups, allowing them to be categorized as high, low, or mid-LG mothers. The 100-day old male offspring of high and low-LG mothers were given the opportunity to learn food preferences for novel diets from conspecifics that had previously eaten these diets (“demonstrators”). Offspring of high-LG mothers socially learned food preferences, but offspring of low-LG mothers did not. We administered oxytocin to subjects to address the hypothesis that it would increase the propensity for social learning, but there were no detectable effects. Our data raise the possibility that social learning propensities may be both relatively stable throughout life and part of a suite of traits “adaptively programmed” by early developmental experiences. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 168–175, 2013
TL;DR: Compared to those previously observed in adults, the components sensitive to emotion in children were maximal over more occipital regions and the LPP component appeared to be less protracted in time, perhaps indicative of less elaborative processing of emotional stimuli.
Abstract: Event-related potentials (ERPs) may be particularly useful for examining emotional processing across development. Though a number of ERP components are sensitive to emotional content in adults, previous studies have yet to systematically examine the components sensitive to emotion in children. The current study used temporal-spatial principal components analysis (PCA) to identify ERP components in response to complex emotional images in nine-year-old children. Three components were modulated by emotional content and were similar to those previously observed in adults, including: the early posterior negativity, the P300, and a sustained relative positivity similar to the late positive potential (LPP). Compared to those previously observed in adults, the components sensitive to emotion in children were maximal over more occipital regions and the LPP component appeared to be less protracted in time, perhaps indicative of less elaborative processing of emotional stimuli.
TL;DR: The current state of understanding about what is and is not reliably predictable from cortisol is summarized and the value of salivary cortisol measurement in developmental research is discussed, addressing whether methodology could be driving research design.
Abstract: Salivary cortisol has been measured extensively in developmental research over the last three decades. The purpose of this article is to summarize the contributions to and limitations of salivary cortisol measurement in developmental research and propose future directions for research that includes salivary cortisol measurement. The properties of cortisol, the history of its burgeoning popularity, and the utility and limitations of (a) cortisol as a biological indicator, (b) saliva as a source of cortisol, and (c) various saliva collection methodologies are described. The current state of understanding about what is and is not reliably predictable from cortisol is summarized and the value of salivary cortisol measurement in developmental research is discussed, addressing whether methodology could be driving research design. Recommendations are made for streamlining study design and reporting within developmental research.
TL;DR: The analysis of trajectories of baseline RSA and vagal withdrawal across the preschool period suggests that children of higher emotionally supportive mothers reached higher levels of physiological regulation earlier in development and therefore did not show the same increase across preschool as children of less supportive mothers.
Abstract: Trajectories of baseline RSA (respiratory sinus arrhythmia), an index of reactivity, and vagal withdrawal, an index of regulation, across the preschool period were examined. In addition, maternal emotional support was investigated as a potential time-varying predictor of these trajectories. Physiological measures were obtained during frustration tasks, and a maternal emotional support measure was assessed via maternal report and direct observation. Children's baseline RSA and vagal withdrawal scores were moderately stable across the preschool period. Growth models indicated that children's baseline RSA scores changed linearly over the preschool years, and there was significant variability in withdrawal trajectories. Greater maternal emotional support predicted higher initial withdrawal levels and lower emotional support was associated with the greatest increase in withdrawal over time. This suggests that children of higher emotionally supportive mothers reached higher levels of physiological regulation earlier in development and therefore did not show the same increase across preschool as children of less supportive mothers. Maternal emotional support was not significantly related to trajectories of baseline RSA.
TL;DR: The present cross-section study is the first to contrast hand preference use for the natural and frequently used reach-to-eat movement with a constructional task that requires a very similar reach- to-grasp movement.
Abstract: The variation in hand use as a function of task and developmental age poses a problem for understanding how and when "handedness," preferred use of one hand, develops. The present cross-section study is the first to contrast hand preference use for the natural and frequently used reach-to-eat movement with a constructional task that requires a very similar reach-to-grasp movement. Thirty children between the ages of 1 and 3 years completed an eating task, in which they grasped small food items (Cheerios™ or Froot Loops™) that they brought to the mouth for eating. Thirty children between the ages of 3 and 5 years completed the construction task, in which they grasped LEGO® pieces to construct 3D models. Hand use preference for grasping in the eating and construction tasks was calculated by comparing the percentage of grasps made by the right hand and by the left hand. There were two main findings: First, right hand preference for grasping in the eating task is present as early as 1 year of age, whereas right hand preference for grasping in the construction task does not develop until 4 years of age. Second, right hand preference for grasping is greater in the eating than in the construction task. The results are discussed in relation to the idea that a consideration for task constraints (e.g., unimanual vs. bimanual; eating vs. construction; natural vs. praxic) should be incorporated into the experimental design when measuring hand use in children.
TL;DR: The results support the importance of the environment during gestation and its interaction with sex and genetics on long-term anxiety and depressive like behaviors.
Abstract: Behavioral effects of different prenatal stress (PNS) schedules were examined in prepubertal "depressive/anxious-like" WKY and control Wistar rats. Pregnant dams received 1 hr daily restraint stress on gestational days 14-20 or on 7 randomly scheduled days, or remained undisturbed. Offspring were tested during postnatal days 29-35 in social play, forced swim-test, open field, and novelty tests. PNS induced an increase in anxiety-like behaviors in WKY, particularly in females, while seemingly reducing depressive-like behavior in the swim test. However, very high post-stress corticosterone levels were found, suggesting that the reductions in swim-test immobility reflect an extremely over-responsive HPA axis, rather than normalization in stress reactivity leading to a less depressive-like profile. In Wistar, PNS produced weight loss, hyperactivity and risk taking behavior, especially in males. The results support the importance of the environment during gestation and its interaction with sex and genetics on long-term anxiety and depressive like behaviors.
TL;DR: Findings support the open nature of stress responsive physiological systems to influence by features of the early caregiving environment and underscore the utility of including measures of these systems in prevention trials designed to influence child outcomes by modifying parenting behavior.
Abstract: Early sociodemographic risk, parenting, and temperament were examined as predictors of the activity of children's (N = 148; 81 boys, 67 girls) hypothalamic-pituitary-adrenal axis and autonomic nervous system. Demographic risk was assessed at 18 months (T1), intrusive/overcontrolling parenting and effortful control were assessed at 30 months (T2), and salivary cortisol and alpha-amylase were collected at 72 (T3) months of age. Demographic risk at T1 predicted lower levels of children's effortful control and higher levels of mothers' intrusive/overcontrolling parenting at T2. Intrusive/overcontrolling parenting at T2 predicted higher levels of children's cortisol and alpha-amylase at T3, but effortful control did not uniquely predict children's cortisol or alpha-amylase levels. Findings support the open nature of stress responsive physiological systems to influence by features of the early caregiving environment and underscore the utility of including measures of these systems in prevention trials designed to influence child outcomes by modifying parenting behavior.
TL;DR: The activity of amniotic fluid and murine milk on neonatal pup behavior before any postnatal suckling experience suggests that either prenatal learning and/or predisposed olfactory mechanisms do operate, while the behavioral activation due to maternal and infantile salivas clearly depends on postnatal exposure.
Abstract: It is a mammalian female strategy to emit odor cues and signals that direct their inexperienced newborns to the nipple, and optimize their initial sucking success and, hence, viability. Here, natural odorous substrates that contribute to nipple grasping were investigated in mice, a species that has not been much scrutinized on this topic. The response of pups toward the nipples of lactating females (LF) versus nonlactating females (NLF) were first assessed right after watched birth, before and after the first suckling experience, and at 1 day old, after more extended suckling experience. It appeared that only nipples of LF induced grasping at these early ages, leading to take NLF as the baseline setting to present various odor substrates sampled from LF, viz. amniotic fluid, murine milk, LF saliva, pup saliva, LF urine, and an odorless control stimulus (water). Results indicate that: (1) only amniotic fluid and fresh milk induced nipple grasping before the first suckling experience; (2) LF saliva started inducing grasping after the first suckling experience; (3) pup saliva released grasping after 24-36 hr of suckling experience; finally (4) neither LF urine, nor water induced any nipple grasping. In conclusion, the activity of amniotic fluid and murine milk on neonatal pup behavior before any postnatal suckling experience suggests that either prenatal learning and/or predisposed olfactory mechanisms do operate, while the behavioral activation due to maternal and infantile salivas clearly depends on postnatal exposure.
TL;DR: It is suggested that newborn rats use movement-related feedback to modulate spontaneous motor activity, and corroborate studies of human infants that have suggested a role for proprioception during early motor development.
Abstract: Perinatal mammals show spontaneous movements that often appear random and uncoordinated. Here, we examined if spontaneous limb movements are responsive to a proprioceptive manipulation by applying a weight unilaterally to a forelimb of postnatal day 0 (P0; day of birth) and P1 rats. Weights were calibrated to approximate 0%, 25%, 50%, or 100% of the average mass of a forelimb, and were attached at the wrist. P0 and P1 pups showed different levels of activity during the period of limb weighting, in response to weight re- moval, and during the period after weighting. Pups exposed to 50% and 100% weights showed proportionately more activity in the nonweighted forelimb during the period of weighting, suggesting a threshold for evoking proprioceptive changes. Findings suggest that newborn rats use movement-related feedback to modulate spontaneous motor activity, and corroborate studies of human infants that have suggested a role for proprioception during early motor develop- ment. 2012 Wiley Periodicals, Inc. Dev Psychobiol
TL;DR: Multilevel modeling analyses showed that infants of mothers with comorbid depression and anxiety had relatively higher cortisol production from morning to bedtime and higher bedtime values as compared to infants of non-depressed mothers and infants of depressed only mothers when they were 6 and 12 months old, but not when 18 months old.
Abstract: The effect of maternal depressive disorder on infant daytime cortisol production was studied in three groups of infants; one group with mothers with comorbid depression and anxiety (n = 19), a second group with mothers with depression only (n = 7), and a third group with non-depressed mothers (n = 24). The infants' cortisol production pattern was measured when they were 6, 12, and 18 months old in combination with repeated measures of parenting stress and depression symptoms. Multilevel modeling analyses showed that infants of mothers with comorbid depression and anxiety had relatively higher cortisol production from morning to bedtime and higher bedtime values as compared to infants of non-depressed mothers and infants of depressed only mothers when they were 6 and 12 months old, but not when 18 months old. The results were interpreted in light of possible changes in the infants' stress regulatory capacities or changes in maternal coping strategies at infant age 18 months. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 334–351, 2013
TL;DR: It is shown how the development of hand-use preferences in proto-reaching skills concatenate into object acquisition skills and eventually into role-differentiated bimanual manipulation skills (that reflect interhemispheric communication and coordination).
Abstract: We propose a developmental process which may link the development of handedness with the development of hemispheric specialization for speech processing. Using Arbib's proposed sequence of sensorimotor development of manual skills and gestures (that he considers to be the basis of speech gestures and proto-language), we show how the development of hand-use preferences in proto-reaching skills concatenate into object acquisition skills and eventually into role-differentiated bimanual manipulation skills (that reflect interhemispheric communication and coordination). These latter sensorimotor skills might facilitate the development of speech processing via their influence on the development of tool-using and object management abilities.
TL;DR: It was showed that rats prenatally exposed to MA were more sensitive to sub-chronic administration of MA in adulthood than pre natally SAL-exposed rats, and gender plays an important role in the sensitivity to MA during prenatal development and in adulthood.
Abstract: The aim of the present study was to compare the response to sub-chronic application of methamphetamine (MA) in adulthood in male and female rats prenatally exposed to the same drug. The spontaneous locomotor activity and exploratory behavior of adult male and female rats prenatally exposed to 5 mg/kg MA or saline (SAL) were tested in a Laboras apparatus (Metris B.V., Netherlands) for five consecutive days, 1 hr daily. MA 1 mg/kg or SAL were used as a challenge prior to testing. Our results showed that rats prenatally exposed to MA were more sensitive to sub-chronic administration of MA in adulthood than prenatally SAL-exposed rats. However, this sensitizing effect of prenatal MA exposure was manifested differently in males and females. In contrast, prenatal MA exposure decreased baseline locomotion in females. This study indicates that gender plays an important role in the sensitivity to MA during prenatal development and in adulthood. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 232–242, 2013
TL;DR: It is suggested that prenatal SRI exposure and the SLC6A4 genotype influences reelin protein expression in both the mother and newborn and that this may be reflected in neonatal behavior.
Abstract: This study was undertaken to determine whether altered early serotonin signaling either via gestational serotonin reuptake inhibitor (SRI) exposure or genetic variations in the serotonin transporter promoter region (SLC6A4) alters levels of reelin, an important glycoprotein in neurodevelopment, in mothers and their neonates. Serum reelin protein expression was quantified by immunoblot from maternal and neonatal blood collected at delivery from women taking either an SRI during gestation or controls. SRI-exposed mothers had higher levels of one reelin fragment, while SRI-exposed neonates had lower total reelin levels, particularly in females and reelin levels differed with SLC6A4 genotype. Lower neonatal reelin levels predicted less time spent sleeping and more irritability during neonatal behavioral assessment on Day 6 of life. Our results suggest that prenatal SRI exposure and the SLC6A4 genotype influences reelin protein expression in both the mother and newborn and that this may be reflected in neonatal behavior.
TL;DR: Marine mammals may share, with humans and other higher primates, a left hemisphere specialization for action dynamics, although evidence is currently lacking for human-like right hemisphere specializations relevant to action in other vertebrates.
Abstract: As part of a vertebrate-wide trend toward left brain/right side asymmetries in routine whole-body actions, marine mammals show signs of rightward appendage-use biases, and short- and long-term turning asymmetries most of which are unique in non-humans in being just as strong as right handedness, and even stronger than human handedness-related turning biases. Short-term marine mammal turning asymmetries and human about-turning asymmetries share a leading right side, suggesting a commonality in left hemisphere intentional control. The long-term leftward turning bias that both groups share may be an indirect result of both sensory and motor influences on the right side in dolphins, but be induced by a right-hemisphere-controlled spatial/attentional bias to the left in humans. Marine mammals may share, with humans and other higher primates, a left hemisphere specialization for action dynamics, although evidence is currently lacking for human-like right hemisphere specializations relevant to action in other vertebrates.
TL;DR: It is outlined how large-scale longitudinal approaches promise to resolve debates and have the potential to use individual difference measures to uncover links to later development.
Abstract: To assess claims about developmental homologies, or devologies, longitudinal data are needed. Here, we illustrate this with the debate about the purported foundational role of neonatal imitation in children's social and cognitive development. Cross-sectional studies over the past 35 years have clarified neither the prevalence of imitation in newborns nor its relationships to later developing skills. Thus, scholars have been able to maintain diametrically opposing explanations of neonatal imitation in the literature. Here, we discuss this issue and outline how large-scale longitudinal approaches promise to resolve such debates and have the potential to use individual difference measures to uncover links to later development.
TL;DR: The transition to an evolutionary approach to homology in which all classes of similarity are interpreted against the single branching tree of life is sketched out, and the evidence for the application of homology across all levels and features of the biological hierarchy, including behavior is outlined.
Abstract: Richard Owen coined the modern definition of homology in 1843. Owen's conception of homology was pre-evolutionary, nontransformative (homology maintained basic plans or archetypes), and applied to the fully formed structures of animals. I sketch out the transition to an evolutionary approach to homology in which all classes of similarity are interpreted against the single branching tree of life, and outline the evidence for the application of homology across all levels and features of the biological hierarchy, including behavior. Owen contrasted homology with analogy. While this is not incorrect it is a pre-evolutionary contrast. Lankester [Lankester [1870] Journal of Natural History, 6 (31), 34-43] proposed homoplasy as the class of homology applicable to features formed by independent evolution. Today we identify homology, convergence, parallelism, and novelties as patterns of evolutionary change. A central issue in homology [Owen [1843] Lectures on comparative anatomy and physiology of the invertebrate animals, delivered at the Royal College of Surgeons in 1843. London: Longman, Brown, Green & Longmans] has been whether homology of features-the "same" portion of the brain in different species, for example-depends upon those features sharing common developmental pathways. Owen did not require this criterion, although he observed that homologues often do share developmental pathways (and we now know, often share gene pathways). A similar situation has been explored in the study of behavior, especially whether behaviors must share a common structural, developmental, neural, or genetic basis to be classified as homologous. However, and importantly, development and genes evolve. As shown with both theory and examples, morphological and behavioral features of the phenotype can be homologized as structural or behavioral homologues, respectively, even when their developmental or genetic bases differ (are not homologous).