Hypoxia can result in brain injury. Hypoxic brain injury can also result in excess stress hormones and activated immune responses. In this study, we examined multiple spontaneous motor behaviors, concentrations of stress hormones, and gene expression of immune responses in rats after perinatal hypoxia. Hypoxic animals exhibited impaired spontaneous motor behaviors in several tests. Perinatal hypoxia also caused increased levels of stress hormones and altered expression of genes associated with adaptive and innate immunity at different time points after hypoxia exposure. Findings demonstrate stress hormones and immune responses are available to play an important role in perinatal brain injury and can impact delayed behavioral development.

This study attempted to examine three aspects of Equus caballus foal snapping behavior. First, it suggested that the previous theoretical explanation for snapping established by behavioral researchers was incorrect. Second, as a means of suggesting an alternative hypothesis, this study proposed that snapping behavior could be a modified play response that was elicited when foals were confused by the complex social signals displayed by conspecifics. Finally, this project tested the aforementioned hypothesis by recording interactions between foals and conspecifics and analyzing the snapping intensity with each subject's previous level of social experience. There were two indicators utilized to establish social experience. First, the "age" of the foal was employed as a measure of overall life experience and development. Second, the number of hours per day the foal was exposed to conspecifics gave an effective measure of the amount of time the subject had an opportunity to learn the complex Equine visual communication (referred to as "out-time"). / Master of Science

Thesis advisor: Rebekah L. Coley / The goal of this dissertation was to delineate the repercussions of early maternal employment for children's early developmental competencies in the U.S., Australia, and the U.K. and to test economic and psychological theories regarding potential mechanisms linking maternal employment with children's development, including time, money, and stress. Prior research has focused on older, non-representative cohorts of American children, with results suggesting full-time employment in the first year after childbirth is linked with lower cognitive and behavioral skills. It is unclear if these same patterns exist in more recent cohorts and in other countries with differing cultural expectations and policy environments for families, most notably more comprehensive parental leave policies. Data came from representative samples of children born in each country between 2000 and 2004: (1) the U.S.'s Early Childhood Longitudinal Study-Birth Cohort (N=10,100), (2) Australia's Longitudinal Study of Australian Children-Birth Cohort (N=5,093), and (3) the U.K.'s Millennium Cohort Study (N= 18,497). In each dataset, mother's employment data were coded to assess the month of entry into employment following childbirth. Extensive, well-validated direct assessment, mother report, and teacher report measures assessed children's cognitive and behavioral skills following entry into formal schooling. Descriptive data showed very different patterns of entry into employment: American mothers entered employment the earliest and at the highest intensity with more gradual, lower intensity returns by Australian and British mothers. OLS regression models weighted with propensity scores and controlling for a rich array of child and maternal characteristics suggested that early movements into employment had few associations with children's cognitive or behavioral skills in any of the countries. These neutral associations were not differentiated by maternal time, stress, or wages. However, as non-maternal household income decreased, early employment was linked with higher cognitive skills in the U.S. while employment begun before two years was linked with higher behavioral skills in Australia. There was no evidence of moderation by non-maternal household income in the U.K. Findings are discussed in terms of their implications for work family policy. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Lynch School of Education. / Discipline: Counseling, Developmental, and Educational Psychology.

A separação materna é um procedimento bastante utilizado com ratos, no qual a prole é privada do contato com a mãe por algumas horas diárias no período anterior ao desmame, observando-se os efeitos sobre o desenvolvimento comportamental e biológico dos filhotes. O objetivo desta tese foi investigar o efeito da separação materna no desenvolvimento de respostas sociais em ratos de ambos os sexos mais especificamente, sobre o brincar social, entre os dias pós-natais 28 e 36; sobre o comportamento sexual, entre a puberdade e a idade adulta; e sobre o comportamento materno, na idade adulta, de fêmeas submetidas à separação materna na infância. Para tanto, os episódios de separação foram conduzidos por 3hs diárias, entre os dias pós-natais 2 e 14, tendo como controle ratos não expostos a esse procedimento. Observou-se que os animais submetidos ao procedimento de separação materna emitiram mais respostas de brincar do que os animais controle. No que se refere ao desenvolvimento sexual, machos submetidos ao procedimento na infância tiveram frequência elevada de respostas de cópula menos efetivas, em detrimento das mais efetivas. Já nas fêmeas, constatou-se um atraso no início da puberdade, além de elas terem se tornado atrativas para machos em idade mais precoce que o grupo controle. Por fim, quando as fêmeas submetidas à separação materna na infância se tornaram mães, suas proles tiveram proporção sexual alterada, com maior número de machos, e índices de mortalidade menores. Ademais, mãe e filhotes foram mais atraídos pelo cheiro do ninho em teste olfativo, em comparação ao grupo controle. Esses resultados sugerem que a separação materna tem efeitos extensos sobre o desenvolvimento de respostas sociais, indicando a necessidade da condução de mais estudos que investiguem os motivos pelos quais esse evento, na infância, leva às alterações observadas / Maternal separation is a frequently used procedure with rats in which the offspring is daily deprived of the contact with the mother during a few hours in the period previous to weaning in order to observe the effects on the behavioral and biological development of the pups. Our aim in this study is to explore the effect of maternal separation on the development of social responses in rats of both sexes, specifically on the social play, between the post-natal days 28 and 26; on the sexual behavior, between puberty and adulthood; and on maternal behavior of females in adulthood that underwent maternal separation during childhood. Therefore, the separation episodes were conducted for 3 hours daily between post-natal days 2 and 14. Rats not exposed to this procedure were used as control. We observed that animals submitted to the maternal separation procedure emitted more play responses than control animals. Regarding sexual development, males submitted to maternal separation had high frequency of less effective copula over more effective copula. The females presented a delay in puberty and became attractive to the males in a more precocious age than the control group. Lastly, when the females submitted to maternal separation became mothers their offspring had altered sexual ratio with a higher number of males and a lower mortality rate. In addition, the mother and her pups were more attracted by the nests odor than the control group in an olfactory test. These results suggest that maternal separation has extensive effects on the development of social responses, indicating the necessity of more studies that investigate why this event in childhood leads to the observed alterations

A separação materna é um procedimento bastante utilizado com ratos, no qual a prole é privada do contato com a mãe por algumas horas diárias no período anterior ao desmame, observando-se os efeitos sobre o desenvolvimento comportamental e biológico dos filhotes. O objetivo desta tese foi investigar o efeito da separação materna no desenvolvimento de respostas sociais em ratos de ambos os sexos mais especificamente, sobre o brincar social, entre os dias pós-natais 28 e 36; sobre o comportamento sexual, entre a puberdade e a idade adulta; e sobre o comportamento materno, na idade adulta, de fêmeas submetidas à separação materna na infância. Para tanto, os episódios de separação foram conduzidos por 3hs diárias, entre os dias pós-natais 2 e 14, tendo como controle ratos não expostos a esse procedimento. Observou-se que os animais submetidos ao procedimento de separação materna emitiram mais respostas de brincar do que os animais controle. No que se refere ao desenvolvimento sexual, machos submetidos ao procedimento na infância tiveram frequência elevada de respostas de cópula menos efetivas, em detrimento das mais efetivas. Já nas fêmeas, constatou-se um atraso no início da puberdade, além de elas terem se tornado atrativas para machos em idade mais precoce que o grupo controle. Por fim, quando as fêmeas submetidas à separação materna na infância se tornaram mães, suas proles tiveram proporção sexual alterada, com maior número de machos, e índices de mortalidade menores. Ademais, mãe e filhotes foram mais atraídos pelo cheiro do ninho em teste olfativo, em comparação ao grupo controle. Esses resultados sugerem que a separação materna tem efeitos extensos sobre o desenvolvimento de respostas sociais, indicando a necessidade da condução de mais estudos que investiguem os motivos pelos quais esse evento, na infância, leva às alterações observadas / Maternal separation is a frequently used procedure with rats in which the offspring is daily deprived of the contact with the mother during a few hours in the period previous to weaning in order to observe the effects on the behavioral and biological development of the pups. Our aim in this study is to explore the effect of maternal separation on the development of social responses in rats of both sexes, specifically on the social play, between the post-natal days 28 and 26; on the sexual behavior, between puberty and adulthood; and on maternal behavior of females in adulthood that underwent maternal separation during childhood. Therefore, the separation episodes were conducted for 3 hours daily between post-natal days 2 and 14. Rats not exposed to this procedure were used as control. We observed that animals submitted to the maternal separation procedure emitted more play responses than control animals. Regarding sexual development, males submitted to maternal separation had high frequency of less effective copula over more effective copula. The females presented a delay in puberty and became attractive to the males in a more precocious age than the control group. Lastly, when the females submitted to maternal separation became mothers their offspring had altered sexual ratio with a higher number of males and a lower mortality rate. In addition, the mother and her pups were more attracted by the nests odor than the control group in an olfactory test. These results suggest that maternal separation has extensive effects on the development of social responses, indicating the necessity of more studies that investigate why this event in childhood leads to the observed alterations

Increasingly, individual variation is being recognized as an important influence on behavioral evolution. Sources of variation are therefore an important target for research into the development, evolution, and function of behavior. By providing information about the timescale on which individuals are responsive to their environment, patterns of within-individual variation can shed light on function of behavioral variation. Here, I wanted to understand the function of behavioral variation and the genetic and environmental sources of variation in behavior. First, I test the hypotheses that variation in begging signals nestling hunger, need, or quality. Hunger is a short-term response to food deprivation, while need and quality give long-term information about fitness benefits of gaining more food and fitness potential, respectively. Second, I test the hypotheses that variation in begging is due to genetic, permanent environment, common environmental, and maternal effects. I test these hypotheses in the begging behavior of western bluebirds (Sialia mexicana), making repeated measurements across the nestling period. I show that begging behavior is consistent across the nestling period, and that nestling begging intensity increases with food deprivation. Nestlings fed during a given parental visit beg at higher intensity than nestmates, and on average wait longer since their last meal compared to individuals who were not fed in the same visit. These results support the hypothesis that variation in nestling begging signals hunger. I also show that responsiveness to food deprivation is negatively related to condition, but this effect is not consistent across the nestling period. Finally, variation in begging is produced by a common environmental effect that is correlated through time, suggesting that begging is strongly influenced by the nest environment. Together, these results indicate that variation in begging signals short-term changes in hunger and that environmental effects dominate the production of variation in begging.

Contexte : Pour les enfants d'âge préscolaire, avoir une télévision dans la chambre à coucher est un facteur de risque connu pour des effets psychologiques et comportementaux indésirables à l'adolescence. Grâce aux bienfaits sur le développement, la participation à des activités sportives pendant l'enfance pourrait agir comme un facteur de protection contre ces associations négatives liées à l’accès privé aux écrans. Les différences entre les sexes en ce qui concerne les habitudes d'écran et du sport prédisposent les garçons et les filles à des risques de psychopathologies développementales distincts. Objectif : Dans cette recherche, nous examinons le rôle modérateur des sports juvéniles dans l’association entre la télévision dans la chambre à coucher au préscolaire et les risques psychosociaux ultérieurs chez les garçons et les filles à 12 ans. Méthode : Cette étude examine 1859 garçons et filles de la cohorte de naissance de l'Étude longitudinale du développement de l'enfant du Québec ayant données sur la présence d’une télévision dans la chambre à coucher. Par la suite, nous examinons les risques psychosociaux rapportées par les enseignants à la fin de la sixième année. Par des régressions linéaires, l'interaction entre le placement d'une télévision dans la chambre à coucher rapporté par l'enfant (4 ans) et les trajectoires de participation sportive durant l'enfance rapportées par les parents (entre 6 et 10 ans) et leur association avec quatre comportements subséquents (12 ans) ont été examinés. Résultats : Chez les garçons, la participation sportive fréquente a amplifié l'association positive entre le une télévision dans la chambre et l'agression physique et les symptômes du TDAH ultérieurs. Chez les filles, la participation sportive moins fréquente a amplifié la relation entre la télévision dans la chambre à coucher et la timidité plus tard. Conclusion : Pour les garçons, la télévision dans la chambre à coucher peut nuire à une adaptation sociale adéquate, ce qui peut contrer les bienfaits attendus du sport. Ceci s’est traduit par une augmentation de l'agressivité physique et des symptômes du TDAH. Pour les filles ayant grandi avec une télévision dans leur chambre, moins d’opportunités sociales telles que le sport organisé était associé à un risque accru de timidité ultérieure. Ces résultats soulignent que la participation au sport parascolaire est un moyen important d'améliorer les interactions et d'acquérir des compétences sociales. / Background: Preschool bedroom television placement represents an established risk factor for negative psychological and behavioral outcomes in adolescence. Sustained childhood sport participation might be a protective factor for potential undesirable associations with having a bedroom screen in early childhood. Sex differences in screen and sport habits makes boys and girls at risk for different developmental psychopathology. Objective: This research examines the moderating role of youth sports on the association between preschool bedroom television and later psychosocial risks at age 12 for boys and girls. Method: This study examines 1859 boys and girls from the Quebec Longitudinal Study of Child Development birth cohort with a history of bedroom television. We examine subsequent teacher-reported psycho-social outcomes by the end of sixth grade. We used linear regression to examine the interaction between child-reported bedroom television placement (age 4 years) and parent-reported childhood sport participation trajectories (ages 6 to 10 years) in predicting four behavioral outcomes (age 12 years). Results: For boys, consistent extracurricular sport amplified the positive relationship between having a preschool bedroom television and subsequent physical aggression and ADHD symptoms. For girls, inconsistent extracurricular sport amplified the relationship between having a preschool bedroom television and subsequent shyness. Conclusion: For boys, bedroom television may inhibit adequate social preparedness which may unexpectedly counter the intended benefits of sport and thus, translate into higher physical aggression and ADHD symptoms. For girls having grown up with a bedroom television, limited exposure to social opportunities such as sport was associated with increased risk of later shyness. The findings corroborate that extracurricular sport is an important venue for enhancing social interactions and skill building.

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