The Impact of Childhood Maltreatment: A Review of Neurobiological and Genetic Factors

Childhood maltreatment represents a significant risk factor for psychopathology. Recent research has begun to examine both the functional and structural neurobiological correlates of adverse care-giving experiences, including maltreatment, and how these might impact on a child’s psychological and emotional development. The relationship between such experiences and risk for psychopathology has been shown to vary as a function of genetic factors. In this review we begin by providing a brief overview of neuroendocrine findings, which indicate an association between maltreatment and atypical development of the hypothalamic–pituitary–adrenal axis stress response, which may predispose to psychiatric vulnerability in adulthood. We then selectively review the magnetic resonance imaging (MRI) studies that have investigated possible structural and functional brain differences in children and adults who have experienced childhood maltreatment. Differences in the corpus callosum identified by structural MRI have now been reliably reported in children who have experienced abuse, while differences in the hippocampus have been reported in adults with childhood histories of maltreatment. In addition, there is preliminary evidence from functional MRI studies of adults who have experienced childhood maltreatment of amygdala hyperactivity and atypical activation of frontal regions. These functional differences can be partly understood in the context of the information biases observed in event-related potential and behavioral studies of physically abused children. Finally we consider research that has indicated that the effect of environmental adversity may be moderated by genotype, reviewing pertinent studies pointing to gene by environment interactions. We conclude by exploring the extent to which the growing evidence base in relation to neurobiological and genetic research may be relevant to clinical practice and intervention

Getting the Phenotypes Right: An Essential Ingredient for Understanding Aetiological Mechanisms Underlying Persistent Violence and Developing Effective Treatments

In order to reduce societal levels of violence, it is essential to advance understanding of the neurobiological mechanisms involved in initiating and maintaining individual patterns of physical aggression. New technologies such as Magnetic Resonance Imagining and analyses of DNA provide tools for identifying these mechanisms. The reliability and validity of the results of studies using these tools depend not only on aspects of the technology, but also on the methodological rigour with which the studies are conducted, particularly with respect to characterizing the phenotype. The present article discusses five challenges confronting scientists who aim to advance understanding of the neurobiological mechanisms associated with persistent violence. These challenges are: (1) to develop evidence-based hypotheses and to design studies that test alternate hypotheses; (2) to recruit samples that are homogeneous with respect to variables that may be linked to neurobiological mechanisms underpinning violent behaviour; (3) to use reliable and valid measures in order to fully characterize participants so that the external validity of the results is evident; (4) to restrict the range of age of participants so as not to confuse developmental change with group differences; and (5) to take account of sex. Our goal is to contribute to elevating methodological standards in this new field of research and to thereby improve the validity of results and move closer to finding effective ways to reduce violence

An ‘embedded brain’ approach to understanding antisocial behaviour

Antisocial behaviour (ASB) incurs substantial costs to the individual and society. Cognitive neuroscience has the potential to shed light on developmental risk for ASB, but it cannot achieve this potential in an ‘essentialist’ framework that focuses on the brain and cognition isolated from the environment. Here, we present the case for studying the social transactional and iterative unfolding of brain and cognitive development in a relational context. This approach, which we call the study of the ‘embedded brain’, is needed to fully understand how risk for ASB arises during development. Concentrated efforts are required to develop and unify methods to achieve this approach and reap the benefits for improved prevention and intervention of ASB

An ‘embedded brain’ approach to understanding antisocial behaviour

Antisocial behaviour (ASB) incurs substantial costs to the individual and society. Cognitive neuroscience has the potential to shed light on developmental risk for ASB, but it cannot achieve this potential in an ‘essentialist’ framework that focuses on the brain and cognition isolated from the environment. Here, we present the case for studying the social transactional and iterative unfolding of brain and cognitive development in a relational context. This approach, which we call the study of the ‘embedded brain’, is needed to fully understand how risk for ASB arises during development. Concentrated efforts are required to develop and unify methods to achieve this approach and reap the benefits for improved prevention and intervention of ASB.</p

Individual differences in sensitivity to the early environment as a function of amygdala and hippocampus volumes: An exploratory analysis in 12-year-old boys

Children differ in their response to environmental exposures, with some being more sensitive to contextual factors than others. According to theory, such variability is the result of individual differences in neurobiological sensitivity to environmental features, with some individuals generally more affected by both negative and/or positive experiences. In this exploratory study we tested whether left and right amygdala and hippocampus volumes (corrected for total brain size) account for individual differences in response to environmental influences in a sample of 62 boys. Cumulative general environmental quality, ranging from low to high, was measured across the first 9 years and child behavior was reported by teachers when boys were 12–13 years old. According to analyses, only the left amygdala volume – not any of the other brain volumes – emerged as an important brain region for sensitivity to positive environmental aspects. Boys with a larger left amygdala benefited significantly more from higher environmental quality than boys with a smaller left amygdala whilst not being more vulnerable to lower quality. Besides providing preliminary evidence for differences in environmental sensitivity due to brain structure, the results also point to the left amygdala as having a specific role regarding the response to environmental influences

Modulation of amygdala response to task-irrelevant emotion

It has been shown that as cognitive demands of a non-emotional task increase, amygdala response to task-irrelevant emotional stimuli is reduced. However, it remains unclear whether effects are due to altered task demands, or altered perceptual input associated with task demands. Here, we present fMRI data from 20 adult males during a novel cognitive conflict task in which the requirement to scan emotional information was necessary for task performance and held constant across levels of cognitive conflict. Response to fearful facial expressions was attenuated under high (vs low) conflict conditions, as indexed by both slower reaction times and reduced right amygdala response. Psychophysiological interaction analysis showed that increased amygdala response to fear in the low conflict condition was accompanied by increased functional coupling with middle frontal gyrus, a prefrontal region previously associated with emotion regulation during cognitive task performance. These data suggest that amygdala response to emotion is modulated as a function of task demands, even when perceptual inputs are closely matched across load conditions. PPI data also show that, in particular emotional contexts, increased functional coupling of amygdala with prefrontal cortex can paradoxically occur when executive demands are lower

Neural processing associated with cognitive and affective Theory of Mind in adolescents and adults

Theory of Mind (ToM) is the ability to attribute thoughts, intentions and beliefs to others. This involves component processes, including cognitive perspective taking (cognitive ToM) and understanding emotions (affective ToM). This study assessed the distinction and overlap of neural processes involved in these respective components, and also investigated their development between adolescence and adulthood. While data suggest that ToM develops between adolescence and adulthood, these populations have not been compared on cognitive and affective ToM domains. Using fMRI with 15 adolescent (aged 11–16 years) and 15 adult (aged 24–40 years) males, we assessed neural responses during cartoon vignettes requiring cognitive ToM, affective ToM or physical causality comprehension (control). An additional aim was to explore relationships between fMRI data and self-reported empathy. Both cognitive and affective ToM conditions were associated with neural responses in the classic ToM network across both groups, although only affective ToM recruited medial/ventromedial PFC (mPFC/vmPFC). Adolescents add- itionally activated vmPFC more than did adults during affective ToM. The specificity of the mPFC/vmPFC response during affective ToM supports evidence from lesion studies suggesting that vmPFC may integrate affective information during ToM. Furthermore, the differential neural response in vmPFC between adult and adolescent groups indicates developmental changes in affective ToM processing

Atypical dorsolateral prefrontal activity in females with conduct disorder during effortful emotion regulation

BACKGROUND: Conduct disorder (CD), which is characterized by severe aggressive and antisocial behavior, is linked to emotion processing and regulation deficits. However, the neural correlates of emotion regulation are yet to be investigated in adolescents with CD. Furthermore, it remains unclear whether CD is associated with deficits in emotional reactivity, emotion regulation, or both. METHODS: We used functional magnetic resonance imaging to study effortful emotion regulation by cognitive reappraisal in 59 female adolescents 15 to 18 years of age (30 with a CD diagnosis and 29 typically developing (TD) control adolescents). RESULTS: Behaviorally, in-scanner self-report ratings confirmed successful emotion regulation within each group individually but significant group differences in emotional reactivity and reappraisal success when comparing the groups (CD < TD). Functional magnetic resonance imaging results revealed significantly lower activation in left dorsolateral prefrontal cortex and angular gyrus in CD compared with TD adolescents during emotion regulation, but no group differences for emotional reactivity. Furthermore, connectivity between left dorsolateral prefrontal cortex and the bilateral putamen, right prefrontal cortex, and amygdala was reduced in CD compared with TD adolescents during reappraisal. Callous-unemotional traits were unrelated to neural activation, but these traits correlated negatively with behavioral reports of emotional reactivity. CONCLUSIONS: Our results demonstrate reduced prefrontal brain activity and functional connectivity during effortful emotion regulation in female adolescents with CD. This sheds light on the neural basis of the behavioral deficits that have been reported previously. Future studies should investigate whether cognitive interventions are effective in enhancing emotion-regulation abilities and/or normalizing prefrontal and temporoparietal activity in female adolescents with CD

APLICAÇÃO DA FIBRA DE COCO NO PROCESSO DE ISOLAMENTO TERMO ACÚSTICO

Por ser um grande consumidor de água de coco, o Brasil possui um problema de descarte dos resíduos gerados por este consumo. Desta forma, pesquisas vêm sendo realizadas para propor aproveitamento deste resíduo do coco, no caso, sua fibra, com alta disponibilidade no país. Esta apresenta baixo custo e propriedades físico-químicas adequadas para confecção de chapas para isolamento termo acústico, representando um alto ganho energético com refrigeração e redução de níveis sonoros de impacto e aéreos, pois absorve as baixas frequências. Assim, este artigo visa fazer revisão bibliográfica sobre o produto e suas aplicações, verificando suas contribuições com relação à conservação ambiental, tanto pelo aproveitamento do resíduo quanto por seu desempenho termo acústico