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1.  Diurnal cortisol amplitude and fronto-limbic activity in response to stressful stimuli 
Psychoneuroendocrinology  2009;34(5):694-704.
The development and exacerbation of many psychiatric and neurologic conditions are associated with dysregulation of the hypothalamic pituitary adrenal (HPA) axis as measured by aberrant levels of cortisol secretion. Here we report on the relationship between the amplitude of diurnal cortisol secretion, measured across 3 typical days in 18 healthy individuals, and blood oxygen level dependant (BOLD) response in limbic fear/stress circuits, elicited by in-scanner presentation of emotionally negative stimuli, specifically, images of the World Trade Center (WTC) attack. Results indicate that subjects who secrete a greater amplitude of cortisol diurnally demonstrate less brain activation in limbic regions, including the amygdala and hippocampus/parahippocampus, and hypothalamus during exposure to traumatic WTC-related images. Such initial findings can begin to link our understanding, in humans, of the relationship between the diurnal amplitude of a hormone integral to the stress response, and those neuroanatomical regions that are implicated as both modulating and being modulated by that response.
PMCID: PMC4250041  PMID: 19135805
Amygdala; Medial prefrontal cortex; Hippocampus; Cortisol; Neuroimaging; Stress
2.  Differential activity of rostral cingulate and brainstem in Panic Disorder and PTSD 
Journal of anxiety disorders  2010;25(2):251-257.
Most functional neuroimaging studies of panic disorder (PD) have focused on the resting state, and have explored PD in relation to healthy controls rather than in relation to other anxiety disorders. Here, PD patients, Posttraumatic stress disorder (PTSD) patients, and healthy control subjects were studied with functional magnetic resonance imaging utilizing an instructed fear conditioning paradigm incorporating both Threat and Safe conditions. Relative to PTSD and control subjects, PD patients demonstrated significantly less activation to the Threat condition and increased activity to the Safe condition in the subgenual cingulate, ventral striatum and extended amygdala, as well as in midbrain periaquaeductal grey, suggesting abnormal reactivity in this key region for fear expression. PTSD subjects failed to show the temporal pattern of activity decrease found in control subjects.
PMCID: PMC4096628  PMID: 21075593
anxiety disorders; panic disorder; posttraumatic stress disorder; subgenual cingulate cortex; ventral striatum; extended amygdala; brainstem; neuroimaging
3.  A consecutive case series experience with [18 F] florbetapir PET imaging in an urban dementia center: impact on quality of life, decision making, and disposition 
Identification and quantification of fibrillar amyloid in brain using positron emission tomography (PET) imaging and Amyvid™ ([18 F] Amyvid, [18 F] florbetapir, 18 F-AV-45) was recently approved by the US Food and Drug Administration as a clinical tool to estimate brain amyloid burden in patients being evaluated for cognitive impairment or dementia. Imaging with [18 F] florbetapir offers in vivo confirmation of the presence of cerebral amyloidosis and may increase the accuracy of the diagnosis and likely cause of cognitive impairment (CI) or dementia. Most importantly, amyloid imaging may improve certainty of etiology in situations where the differential diagnosis cannot be resolved on the basis of standard clinical and laboratory criteria.
A consecutive case series of 30 patients (age 50-89; 16 M/14 F) were clinically evaluated at a cognitive evaluation center of urban dementia center and referred for [18 F] florbetapir PET imaging as part of a comprehensive dementia workup. Evaluation included neurological examination and neuropsychological assessment by dementia experts. [18 F] florbetapir PET scans were read by trained nuclear medicine physicians using the qualitative binary approach. Scans were rated as either positive or negative for the presence of cerebral amyloidosis. In addition to a comprehensive dementia evaluation, post [18 F] florbetapir PET imaging results caused diagnoses to be changed in 10 patients and clarified in 9 patients. Four patients presenting with SCI were negative for amyloidosis. These results show that [18 F] florbetapir PET imaging added diagnostic clarification and discrimination in over half of the patients evaluated.
Amyloid imaging provided novel and essential data that: (1) caused diagnosis to be revised; and/or (2) prevented the initiation of incorrect or suboptimal treatment; and/or (3) avoided inappropriate referral to an anti-amyloid clinical trial.
PMCID: PMC3913628  PMID: 24484858
Amyvid™; Florbetapir; PET; Clinical series; Alzheimer’s disease; Neuroimaging
4.  Clinical importance of delayed MRI contrast enhancement of primary central nervous system lymphoma in AIDS 
BMJ Case Reports  2009;2009:bcr10.2008.1043.
Accurately distinguishing between cerebral toxoplasmosis and primary central nervous system lymphoma (PCNSL), still the most common secondary CNS mass lesion complications of AIDS, has long represented a diagnostic challenge in those with HIV. A young adult male with AIDS presented with evolving ophthalmoplegias, Parinaud’s syndrome and gait dysfunction. MRI with gadolinium contrast revealed a brainstem lesion failing to enhance on initially obtained post-contrast images yet prominently enhancing on images acquired endmost within the same scanning session. Biopsy ultimately confirmed lesion aetiology as PCNSL. While the definitive diagnosis of PCNSL generally requires brain biopsy, different MRI contrast-enhancement time courses of PCNSL versus toxoplasmosis (PCNSL tends to peak-enhance sooner than toxoplasmosis) can provide differential diagnostic insight. These images underscore the delayed nature of PCNSL contrast enhancement and demonstrate the diagnostic importance of attending to post-gadolinium image acquisition timing to help inform utilisation of MRI for PCNSL identification.
PMCID: PMC3027744  PMID: 21686485
5.  The Impact of Socioeconomic Status on the Neural Substrates Associated with Pleasure 
Low socio-economic status (SES) is associated with increased morbidity and premature mortality. Because tonic adversity relates to a diminished ability to experience pleasure, we hypothesized that subjects living in poverty would show diminished neural responsivity to positive stimuli in regions associated with positive experience and reward. Visual images were presented to twenty-two subjects in the context of a EPI-BOLD fMRI paradigm. Significant differences in neural responses between SES groups to poverty vs. neutral images were assessed, examining group, condition, and interaction effects. The data suggest that persons living in low-SES have neural experiences consistent with diminished interest in things generally enjoyed and point toward a possible explanation for the relationship between socioeconomic inequalities and mood disorders, such as depression, by SES.
PMCID: PMC2731107  PMID: 19718457
fMRI; depression; mood; stress; socio-economic status.

Results 1-6 (6)