Biological psychiatry
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Biological psychiatry · Nov 2007
Enduring effects of infant memories: infant odor-shock conditioning attenuates amygdala activity and adult fear conditioning.
Early life adverse experience alters adult emotional and cognitive development. Here we assess early life learning about adverse experience and its consequences on adult fear conditioning and amygdala activity. ⋯ This suggests some enduring effects of early life adversity (shock) are under CS control and dependent upon learning for their impact on later adult fear learning.
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Biological psychiatry · Sep 2007
Comparative StudyThe association of major depression, conduct disorder, and maternal overcontrol with a failure to show a cortisol buffered response in 4-month-old infants of teenage mothers.
Adolescent pregnancy can be associated with major depression (MD) and conduct disorder (CD). Some infants of adolescent mothers are prenatally exposed to these factors, which may result in heightened risk for perturbations of their stress systems. Between 2 and 4 months, a normal shift occurs in the adrenocortical system in which we observe a marked decrease in infant cortisol response when facing mild stressors. This study aimed to explore whether MD (lifetime, during pregnancy, postpartum), CD, and maternal overcontrol are associated with increased cortisol reactivity in 4-month-old infants of teenage mothers. ⋯ Future studies should detect whether the absence of a dampened cortisol response in infants whose mothers have lifetime MD or display overcontrolling parenting is stable over time.
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Biological psychiatry · Sep 2007
Resting-state functional connectivity in major depression: abnormally increased contributions from subgenual cingulate cortex and thalamus.
Positron emission tomography (PET) studies of major depression have revealed resting-state abnormalities in the prefrontal and cingulate cortices. Recently, fMRI has been adapted to examine connectivity within a specific resting-state neural network--the default-mode network--that includes medial prefrontal and anterior cingulate cortices. The goal of this study was to examine resting-state, default-mode network functional connectivity in subjects with major depression and in healthy controls. ⋯ This is the first study to explore default-mode functional connectivity in major depression. The findings provide cross-modality confirmation of PET studies demonstrating increased thalamic and subgenual cingulate activity in major depression. Further, the within-subject connectivity analysis employed here brings these previously isolated regions of hypermetabolism into the context of a disordered neural network. The correlation between refractoriness and subgenual cingulate functional connectivity within the network suggests that a quantitative, resting-state fMRI measure could be used to guide therapy in individual subjects.
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Biological psychiatry · Aug 2007
Hippocampal volume and mood disorders after traumatic brain injury.
Recent evidence from clinical studies and animal models of traumatic brain injury (TBI) suggest that neuronal and glial loss might progress after the initial insult in selectively vulnerable regions of the brain such as the hippocampus. There is also evidence that hippocampal dysfunction plays a role in the pathogenesis of mood disorders. We examined the relationship between hippocampal damage and mood disorders after TBI and the effect of hippocampal atrophy on the outcome of TBI patients. ⋯ Our findings are consistent with a "double-hit" mechanism by which neural and glial elements already affected by trauma are further compromised by the functional changes associated with mood disorders (e.g., the neurotoxic effects of increased levels of cortisol or excitotoxic damage resulting from overactivation of glutaminergic pathways). Finally, patients with greater hippocampal damage were less likely to return to a productive life 1 year after trauma.
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Biological psychiatry · Aug 2007
Risperidone exerts potent anti-aggressive effects in a developmentally immature animal model of escalated aggression.
Risperidone has been shown to be clinically effective for the treatment of aggressive behavior in children, yet no information is available regarding whether risperidone exhibits aggression-specific suppression in preclinical studies that use validated developmentally immature animal models of escalated aggression. Previously, we have shown that exposure to low doses of the psychostimulant cocaine-hydrochloride (.5 mg/kg intraperitoneally) during the majority of pubertal development (postnatal days [P]27-57) generates animals that exhibit a high level of offensive aggression. This study examined whether risperidone exerts selective aggression-suppressing effects by using this pharmacologic animal model of highly escalated offensive aggression. ⋯ These studies provide evidence that risperidone exerts specific aggression-suppressing effects in a developmentally immature animal model of escalated aggression.