Phyllis Chua

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Patients with generalized social anxiety disorder (GSAD) exhibit heightened activation of the amygdala in response to social cues conveying threat (eg, fearful/angry faces). The neuropeptide oxytocin (OXT) decreases anxiety and stress, facilitates social encounters, and attenuates amygdala reactivity to threatening faces in healthy subjects. The goal of(More)
Functional integrity of prefrontal cortico-striatal circuits underlying executive functioning may be compromised by basal ganglia degeneration during Huntington's disease (HD). This study investigated challenged inhibitory attentional control with a shifting response-set (SRS) task whilst assessing neural response via functional magnetic resonance imaging(More)
BACKGROUND Functional neural impairments have been documented in people with symptomatic Huntington disease (symp-HD) and in premanifest gene carriers (pre-HD). This study aimed to characterize synchrony in resting state cerebral networks in both pre-HD and symp-HD populations and to determine its association with disease burden and neurocognitive(More)
We investigated two measures of neural integrity, T1-weighted volumetric measures and diffusion tensor imaging (DTI), and explored their combined potential to differentiate pre-diagnosis Huntington's disease (pre-HD) individuals from healthy controls. We applied quadratic discriminant analysis (QDA) to discriminate pre-HD individuals from controls and we(More)
OBJECTIVES The aims of this study were to follow a cohort of HIV-infected individuals for 2 years to assess changes in depression and neuropsychological performance over time, to explore the relationship between depression, HIV illness and neuropsychological performance, and to examine the natural history of the effect of highly active antiretroviral(More)
Cognitive deficits in Huntington's disease (HD) have been attributed to neuronal degeneration within the striatum; however, postmortem and structural imaging studies have revealed more widespread morphological changes. To examine the impact of HD-related changes in regions outside the striatum, we used functional magnetic resonance imaging (fMRI) in HD to(More)
Generalized social anxiety disorder (GSAD) is associated with heightened limbic and prefrontal activation to negative social cues conveying threat (e.g. fearful faces), but less is known about brain response to negative non-threatening social stimuli. The neuropeptide oxytocin (Oxt) has been shown to attenuate (and normalize) fear-related brain activation(More)
OBJECTIVE To investigate structural connectivity and the relationship between axonal microstructure and clinical, cognitive, and motor functions in premanifest (pre-HD) and symptomatic (symp-HD) Huntington's disease. METHOD Diffusion tensor imaging (DTI) data were acquired from 35 pre-HD, 36 symp-HD, and 35 controls. Structural connectivity was mapped(More)
OBJECTIVE To quantify 18-month changes in white matter microstructure in premanifest (pre-HD) and symptomatic Huntington's disease (symp-HD). To investigate baseline clinical, cognitive and motor symptoms that are predictive of white matter microstructural change over 18months. METHOD Diffusion tensor imaging (DTI) data were analyzed for 28 pre-HD, 25(More)
OBJECTIVE The striatum and its projections are thought to be the earliest sites of Huntington's disease (HD) pathology. This study aimed to investigate progression of striatal pathology in symptomatic HD using diffusion tensor imaging. METHOD Diffusion weighted images were acquired in 18 HD patients and in 17 healthy controls twice, 1 year apart. Mean(More)