Neuroscience
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Volatile organic solvent abuse continues to be a worldwide health problem, including the neurobehavioral teratogenic sequelae of toluene abuse during pregnancy. Although abuse levels of prenatal toluene exposure can lead to a Fetal Solvent Syndrome, there is little research examining these effects on memory. Consumption of toluene can have detrimental effects on the developing hippocampus which could lead to specific spatial learning and memory deficits. ⋯ Male and female offspring (N=104) were observed in the MWM for 5days beginning on postnatal day (PN) 28 and again on PN44. While prenatal toluene-exposed animals did not differ in initial acquisition in the MWM, rats prenatally exposed to 12,000ppm toluene displayed performance deficits during a probe trial and in reversal learning on PN44. Overall, this study indicates that prenatal exposure to repeated inhaled abuse patterns of high concentrations of toluene can impair spatial memory function that persists into adolescence.
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Randomized Controlled Trial
Early deprivation, atypical brain development, and internalizing symptoms in late childhood.
Children exposed to extreme early-life neglect such as in institutional rearing are at heightened risk for developing depression and anxiety disorders, and internalizing problems more broadly. These outcomes are believed to be due to alterations in the development of neural circuitry that supports emotion regulation. The specific neurodevelopmental changes that contribute to these difficulties are largely unknown. ⋯ Internalizing symptoms were assessed at the time of the MRI scan, and once children reached 12-14years of age. Results indicated that neglect-associated alterations in the external capsule and corpus callosum partially explained links between institutional rearing status and internalizing symptoms in middle childhood and early adolescence. Findings shed light on neural mechanisms contributing to increased risk for emotional difficulties among children reared in adverse conditions and have implications for prevention and intervention.
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Thyroid hormones (THs) play an obligatory role in many fundamental processes underlying brain development and maturation. The developing embryo/fetus is dependent on maternal supply of TH. The fetal thyroid gland does not commence TH synthesis until mid gestation, and the adverse consequences of severe maternal TH deficiency on offspring neurodevelopment are well established. ⋯ Next, we consider and discuss whether and how processes related to maternal stress and stress biology may interact with and modify the effects of maternal thyroid function on offspring brain development. We synthesize several research areas and identify important knowledge gaps that may warrant further study. The scientific and public health relevance of this review relates to achieving a better understanding of the timing, mechanisms and contexts of thyroid programing of brain development, with implications for early identification of risk, primary prevention and intervention.
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Traumatic experiences early in life predispose animals and humans to later cognitive-behavioral, emotional, and somatic problems. In humans, traumatic experiences are strong predictors of psychiatric illness. A growing body of research has emphasized alterations in neurological structure and function that underscore phenotypic changes following trauma. ⋯ In line with this, we discuss the long-standing challenge of separating effects of chronic stress and trauma, as these are often intertwined. We bring to light inconsistencies in localization of neural correlates of trauma, emphasizing results in medial prefrontal regions. We assert that more precise spatial brain localization will help to advance prevailing models of trauma pathways and inform future research.
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The prenatal and postnatal early-life periods are both dynamic and vulnerable windows for brain development. During these important neurodevelopmental phases, essential processes and structures are established. Exposure to adverse events that interfere with this critical sequence of events confers a high risk for the subsequent emergence of mental illness later in life. ⋯ Due to the bidirectional communication between the gut and the brain, it is possible that aberrant situations affecting either organ in early life can impact on the other. Studies have now shown that deviations from the gold standard trajectory of gut microbiota establishment and development in early life can lead not only to disorders of the gastrointestinal tract but also complex metabolic and immune disorders. These are being extended to disorders of the central nervous system and understanding how the gut microbiome shapes brain and behavior during early life is an important new frontier in neuroscience.