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331
Benefits and costs of increased levels of corticosterone in seabird chicks, Horm. Behav
, 2003
"... seabird chicks ..."
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Biological sensitivity to context II: Empirical explorations of an evolutionary-developmental theory. Development and Psychopathology
, 2005
"... In two studies comprising 249 children and their families, the authors utilized secondary, exploratory data analyses to examine Boyce and Ellis ’ ~this issue! evolutionary–developmental theory of biological sensitivity to context. The theory proposes that individual differences in stress reactivity ..."
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Cited by 32 (6 self)
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In two studies comprising 249 children and their families, the authors utilized secondary, exploratory data analyses to examine Boyce and Ellis ’ ~this issue! evolutionary–developmental theory of biological sensitivity to context. The theory proposes that individual differences in stress reactivity constitute variation in susceptibility to environmental influence, both positive and negative, and that early childhood exposures to either highly protective or acutely stressful environments result in heightened reactivity. In Study 1, 127 3- to 5-year old children were concurrently assessed on levels of support0adversity in home and preschool environments and on cardiovascular reactivity to laboratory challenges. In Study 2, 122 children were prospectively assessed on familial stress in both infancy and preschool and on autonomic and adrenocortical reactivity to laboratory challenges at age 7. In both studies, a disproportionate number of children in supportive, low stress environments displayed high autonomic reactivity. Conversely, in Study 2, a relatively high proportion of children in very stressful environments showed evidence of heightened sympathetic and adrenocortical reactivity. Consistent with the evolutionary–developmental theory, the exploratory analyses also generated the testable hypothesis that relations between levels of childhood support0adversity and the magnitude of stress reactivity are curvilinear, with children from moderately stressful environments displaying the lowest reactivity levels in both studies.
Research review: the neurobiology and genetics of maltreatment and adversity
- Journal of Child Psychology and Psychiatry
, 2010
"... The neurobiological mechanisms by which childhood maltreatment heightens vulnerability to psycho-pathology remain poorly understood. It is likely that a complex interaction between environmental experiences (including poor caregiving) and an individual’s genetic make-up influence neurobiological dev ..."
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Cited by 29 (1 self)
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The neurobiological mechanisms by which childhood maltreatment heightens vulnerability to psycho-pathology remain poorly understood. It is likely that a complex interaction between environmental experiences (including poor caregiving) and an individual’s genetic make-up influence neurobiological development across infancy and childhood, which in turn sets the stage for a child’s psychological and emotional development. This review provides a concise synopsis of those studies investigating the neurobiological and genetic factors associated with childhood maltreatment and adversity. We first provide an overview of the neuroendocrine findings, drawing from animal and human studies. These studies indicate an association between early adversity and atypical development of the hypothalamic-pituitary-adrenal (HPA) axis stress response, which can predispose to psychiatric vulnerability in adulthood. We then review the neuroimaging findings of structural and functional brain differences in children and adults who have experienced childhood maltreatment. These studies offer evidence of several structural differences associated with early stress, most notably in the corpus callosum in children and the hippocampus in adults; functional studies have reported atypical activation of several brain regions, including decreased activity of the prefrontal cortex. Next we consider studies that suggest that the effect of environmental adversity may be conditional on an individual’s genotype. We also briefly consider the possible role that epigenetic mechanisms might play in mediating the impact of early adversity. Finally we consider several ways in which the neurobiological and genetic research may be relevant to clinical practice and intervention. Keywords: Child abuse, maltreatment, neuroscience, genetics, HPA, psychopathology, resilience, cortisol. There is a burgeoning interest in understanding how early adverse experiences impact on the developing brain (e.g., Caspi & Moffitt, 2006; Lupien, McEwen,
Stress and plasticity in the limbic system
- Neurochemical Research
, 2003
"... The adult nervous system is not static, but instead can change, can be reshaped by experience. Such plasticity has been demonstrated from the most reductive to the most integrated levels, and understanding the bases of this plasticity is a major challenge. It is apparent that stress can alter plasti ..."
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Cited by 26 (0 self)
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The adult nervous system is not static, but instead can change, can be reshaped by experience. Such plasticity has been demonstrated from the most reductive to the most integrated levels, and understanding the bases of this plasticity is a major challenge. It is apparent that stress can alter plasticity in the nervous system, particularly in the limbic system. This paper reviews that subject, concentrating on: a) the ability of severe and/or prolonged stress to impair hippocampaldependent explicit learning and the plasticity that underlies it; b) the ability of mild and transient stress to facilitate such plasticity; c) the ability of a range of stressors to enhance implicit fear conditioning, and to enhance the amygdaloid plasticity that underlies it.
The Environment and
- Department of Human Geography, Uppsala University
, 1992
"... This article presents a survey of authorisation models and considers their ‘fitness-for-purpose ’ in facilitating information sharing. Network-supported information sharing is an important technical capability that underpins collaboration in support of dynamic and unpredictable activities such as em ..."
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Cited by 24 (0 self)
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This article presents a survey of authorisation models and considers their ‘fitness-for-purpose ’ in facilitating information sharing. Network-supported information sharing is an important technical capability that underpins collaboration in support of dynamic and unpredictable activities such as emergency response, national security, infrastructure protection, supply chain integration and emerging business models based on the concept of a ‘virtual organisation’. The article argues that present authorisation models are inflexible and poorly scalable in such dynamic environments due to their assumption that the future needs of the system can be predicted, which in turn justifies the use of persistent authorisation policies. The article outlines the motivation and requirement for a new flexible authorisation model that addresses the needs of information sharing. It proposes that a flexible and scalable authorisation model must allow an explicit specification of the objectives of the system and access decisions must be made based on a late trade-off analysis between these explicit objectives. A research agenda for the proposed Objective-Based Access Control concept is presented. c ○ 2010 ISC. All rights reserved. 1
The sensitive hare: sublethal effects of predator stress on reproduction in snowshoe hares
- Journal of Animal Ecology
, 2009
"... 1. Prey responses to high predation risk can bemorphological or behavioural and ultimately come at the cost of survival, growth, body condition, or reproduction. These sub-lethal predator effects have been shown to be mediated by physiological stress. We tested the hypothesis that elevated glucocort ..."
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Cited by 18 (3 self)
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1. Prey responses to high predation risk can bemorphological or behavioural and ultimately come at the cost of survival, growth, body condition, or reproduction. These sub-lethal predator effects have been shown to be mediated by physiological stress. We tested the hypothesis that elevated glucocorticoid concentrations directly cause a decline in reproduction in individual free-ranging female snowshoe hares, Lepus americanus. Wemeasured the cortisol concentration from each dam (using a faecal analysis enzyme immunoassay) and her reproductive output (litter size, offspring birthmass, offspring right hind foot (RHF) length) 30 h after birth. 2. In a natural monitoring study, we monitored hares during the first and second litter from the population peak (2006) to the second year of the decline (2008). We found that faecal cortisol metabolite (FCM) concentration in dams decreased 52 % from the first to the second litter. From the first to the second litter, litter size increased 122%, offspring body mass increased 130%, and offspring RHF length increased 112%. Dam FCM concentrations were inversely related to litter size (r2 0Æ19), to offspring birth mass (r2 0Æ32), and to offspring RHF length (r2 0Æ64). 3. In an experimental manipulation, we assigned wild-caught, pregnant hares to a control and a stressed group and held them in pens. Hares in the stressed group were exposed to a dog 1–2 min
Coping with changing northern environments: the role of the stress axis in birds and mammals
- Integr. Comp. Biol
, 2004
"... SYNOPSIS. Northern environments present ecological and physiological problems for homeotherms that require adaptations to cope with severe and less predictable physical factors while at the same time continuing to have to cope with the biological ones, such as competition and predation. The stress a ..."
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Cited by 18 (4 self)
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SYNOPSIS. Northern environments present ecological and physiological problems for homeotherms that require adaptations to cope with severe and less predictable physical factors while at the same time continuing to have to cope with the biological ones, such as competition and predation. The stress axis plays a central role in these adaptations and I discuss the range of solutions that birds and mammals have evolved. The stress response in these animals is not static when a challenge occurs, but may be modulated depending on the biological function during the annual cycle (breeding versus nonbreeding), either under-responding to permit reproduction (some song birds) or responding vigorously, yet not having this compromise reproduction (Arctic ground squirrels). Both may trade off survival for reproduction. In contrast, the snowshoe hare shows the expected stress response to chronic high predation risk over 2–3 years: body resources are geared to survival and reproduction is inhibited. Two long term, persistent, and pervasive changes will confront northern birds and mammals in the 21st century: global change and persistent organochlorine pollutants (POPs). These may result in either adaptations or shifts in distribution and abundance. For the former, latitudinal variation in the stress axis may help song birds respond rapidly; population variation in the stress axis response is unknown in northern mammals and relatively sedentary mammals may be unable to shift their distribution rapidly to adjust major climate shifts. For the latter, the few POPs studies that have examined the stress axis indicate marked negative effects.
Stress response and the value of reproduction: are birds prudent parents?
- Am. Nat.
, 2009
"... abstract: In vertebrates, stressors such as starvation or predator attacks stimulate the rapid elevation of circulating glucocorticoid hormones, triggering physiological and behavioral responses that aid immediate survival but simultaneously inhibit reproduction. This stress response has been propo ..."
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Cited by 17 (5 self)
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abstract: In vertebrates, stressors such as starvation or predator attacks stimulate the rapid elevation of circulating glucocorticoid hormones, triggering physiological and behavioral responses that aid immediate survival but simultaneously inhibit reproduction. This stress response has been proposed to serve as a physiological mediator of life-history trade-offs: when the value of current reproduction is high relative to the value of future reproduction and survival, a mitigated stress response is expected to enable successful breeding and maximize fitness. Using phylogenetic comparative analyses, we investigated baseline and peak stress-induced plasma corticosterone levels during parental care in 64 bird species. We found that (1) species with a higher value of the current brood relative to future breeding mounted weaker corticosterone responses during acute stress, and (2) females in species with more female-biased parental care had weaker corticosterone responses. These results support the brood value hypothesis, suggesting that the stress response evolves as an adaptive basis for life-history strategies. Further, we found that (3) baseline corticosterone correlated positively with brood value and negatively with body mass, and (4) peak corticosterone was greater in species breeding at higher latitudes. The latter findings suggest that circulating corticosterone concentrations might be matched to the anticipated demands and risks during nesting.
Endocrinology of complex life cycles: amphibians
- In Hormones, brain and behavior
, 2002
"... COMPLEX LIFE CYCLES Amphibians exhibit considerable diversity in behavioral, physiological, and life history strategies. They are geographically widespread, occupying a diverse range ..."
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Cited by 16 (2 self)
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COMPLEX LIFE CYCLES Amphibians exhibit considerable diversity in behavioral, physiological, and life history strategies. They are geographically widespread, occupying a diverse range
Endocrine mediation of vertebrate male alternative reproductive tactics: the next generation of studies
- Integr. Comp. Biol
, 2004
"... SYNOPSIS. In many species of animals, males may achieve reproductive success via one of several alternative reproductive tactics. Over the past decade or so, there has been a concerted effort to investigate endocrine mechanisms that underlie such discrete behavioral (and often morphological) variati ..."
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Cited by 15 (1 self)
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SYNOPSIS. In many species of animals, males may achieve reproductive success via one of several alternative reproductive tactics. Over the past decade or so, there has been a concerted effort to investigate endocrine mechanisms that underlie such discrete behavioral (and often morphological) variation. In vertebrates, the first generation of studies focused on potential organizational or activational effects of steroid hormones (Moore, 1991; Moore et al., 1998). Some of these studies have made it clear that, in addition to circulating hormone levels, one must also consider other aspects of the endocrine system, including hormone receptors, binding globulins and potential interactions among endocrine axes. In this paper, I review recent work on endocrine mechanisms and suggest possibilities for future investigation. I highlight how individual variation in sensitivity to environmental conditions, particularly with respect to various stressors, may account for the existence of alternative male reproductive phenotypes. Along these lines, I briefly explain the logic behind our work with male phenotypes of longear sunfish (Lepomis megalotis) that is aimed at determining the tissue-specific distribution and activity of two enzymes that are common to androgen and glucocorticoid metabolism. A major goal of our work is to examine the potential role of steroidogenic enzymes in the transduction of environmental information to influence the expression of alternative male reproductive phe-notypes.