Publications by authors named "Andrew Breeden"

Affective science is a broad and burgeoning field, and the National Institutes of Health (NIH) support research on a similarly broad range of topics. Across NIH, funding is available for basic, translational, and intervention research, including research in non-human animals, healthy populations, and those with or at risk for disease. Multiple NIH Institutes and Centers have specific programs devoted to topics within the affective science umbrella.

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  • Noninvasive brain stimulation (NIBS) shows promise for treating psychiatric and neurological issues, but its effectiveness varies among individuals.
  • Targeting specific "hub" brain areas identified through individual brain networks may enhance the cognitive effects of NIBS interventions.
  • Research indicates that inhibiting these hub areas disrupts cognitive functions, like working memory, more than targeting non-hub areas, suggesting the importance of individual brain network features in optimizing NIBS treatments.
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  • - The study investigates the link between callous unemotional (CU) traits in youths and the volume of the amygdala, which is believed to be dysfunctional in individuals with these traits and associated externalizing behaviors.
  • - Assessing 148 youths through specific psychological inventories and brain imaging, researchers found that CU traits correlate with higher externalizing behaviors and reduced amygdala volume, primarily influenced by the callous and uncaring aspects of CU traits.
  • - The results suggest that these callous-uncaring traits could mediate the connection between smaller amygdala volume and the severity of externalizing behaviors, highlighting the role of amygdala development in understanding conduct problems in youths.
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  • Comorbid executive dysfunction in autism spectrum disorder (ASD) hinders adaptive functioning even when core symptoms improve, highlighting a need to focus on this area in ASD research.
  • A study with 75 children (35 with ASD) found that typical developing children showed increased brain network adaptability during tasks, while children with ASD did not.
  • The inability of certain brain regions to serve as adaptive hubs may underlie executive impairments in ASD, suggesting new avenues for understanding this condition and identifying potential biomarkers.
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Callous-unemotional (CU) traits characterize a subgroup of youths with conduct problems who exhibit low empathy, fearlessness, and elevated externalizing behaviors. The current study examines the role of aberrant amygdala activity and functional connectivity during a socioemotional judgment task in youths with CU traits, and links these deficits to externalizing behaviors. Functional magnetic resonance imaging was used to compare neural responses in 18 healthy youths and 30 youths with conduct problems and varying levels of CU traits as they evaluated the acceptability of causing another person to experience each of several emotions, including fear.

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Background: Urea cycle disorders are caused by dysfunction in any of the six enzymes and two transport proteins involved in urea biosynthesis. Our study focuses on ornithine transcarbamylase deficiency (OTCD), an X-linked disorder that results in a dysfunctional mitochondrial enzyme, which prevents the synthesis of citrulline from carbamoyl phosphate and ornithine. This enzyme deficiency can lead to hyperammonemic episodes and severe cerebral edema.

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We examined whether altered connectivity in functional networks during working memory performance persists following conclusion of that performance, into a subsequent resting state. We conducted functional magnetic resonance imaging (fMRI) in 50 young adults during an initial resting state, followed by an N-back working memory task and a subsequent resting state, in order to examine changes in functional connectivity within and between the default-mode network (DMN) and the task-positive network (TPN) across the three states. We found that alterations in connectivity observed during the N-back task persisted into the subsequent resting state within the TPN and between the DMN and TPN, but not within the DMN.

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The urea-cycle disorders (UCDs) are a group of congenital enzyme and carrier deficiencies predisposing to hyperammonemia (HA). HA causes changes in the central nervous system (CNS) including alterations of neurotransmitter function, cell volume, and energy deprivation ultimately leading to cerebral edema. Neuropathological findings of UCDs primarily reflect changes in astrocyte morphology.

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Background: Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle disorder characterized by hyperammonemia resulting in white matter injury and impairments in working memory and executive cognition.

Objective: To test for differences in BOLD signal activation between subjects with OTCD and healthy controls during a working memory task.

Design, Setting And Patients: Nineteen subjects with OTCD and 21 healthy controls participated in a case-control, IRB-approved study at Georgetown University Medical Center.

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Risky decision making is a hallmark behavioral phenotype of drug abuse; thus, an understanding of its biological bases may inform efforts to develop therapies for addictive disorders. A neurocognitive task that measures this function (Rogers Decision-Making Task; RDMT) was paired with measures of regional cerebral perfusion to identify brain regions that may underlie deficits in risky decision making in drug abusers. Subjects were abstinent drug abusers (> or =3 months) and healthy controls who underwent positron emission tomography scans with H(2)(15)O.

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