Browsing by Subject "functional MRI"

Now showing 1 - 3 of 3
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    Chemotherapy-induced amenorrhea: a prospective study of brain activation changes and neurocognitive correlates
    (Springer US, 2013-12) Conroy, Susan K.; McDonald, Brenna C.; Ahles, Tim A.; West, John D.; Saykin, Andrew J.; Department of Radiology and Imaging Sciences, School of Medicine
    Chemotherapy-induced amenorrhea (CIA) often occurs in pre- and peri-menopausal BC patients, and while cancer/chemotherapy and abrupt estrogen loss have separately been shown to affect cognition and brain function, studies of the cognitive effects of CIA are equivocal, and its effects on brain function are unknown. Functional MRI (fMRI) during a working memory task was used to prospectively assess the pattern of brain activation and deactivation prior to and one month after chemotherapy in BC patients who experienced CIA (n=9), post-menopausal BC patients undergoing chemotherapy (n=9), and pre- and post-menopausal healthy controls (n=6 each). Neurocognitive testing was also performed at both time points. Repeated measures general linear models were used to assess statistical significance, and age was a covariate in all analyses. We observed a group-by-time interaction in the combined magnitudes of brain activation and deactivation (p = 0.006): the CIA group increased in magnitude from baseline to post-treatment while other groups maintained similar levels over time. Further, the change in brain activity magnitude in CIA was strongly correlated with change in processing speed neurocognitive testing score (r=0.837 p=0.005), suggesting this increase in brain activity reflects effective cognitive compensation. Our results demonstrate prospectively that the pattern of change in brain activity from pre- to post-chemotherapy varies according to pre-treatment menopausal status. Cognitive correlates add to the potential clinical significance of these findings. These findings have implications for risk appraisal and development of prevention or treatment strategies for cognitive changes in CIA.
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    Developmental Resting State Functional Connectivity for Clinicians
    (Springer International Publishing, 2014-09-01) Hulvershorn, Leslie A.; Cullen, Kathryn R.; Francis, Michael; Westlund, Mindy; Department of Psychiatry, IU School of Medicine
    Resting state functional magnetic imaging (fMRI) is a novel means to examine functional brain networks. It allows investigators to identify functional networks defined by distinct, spontaneous signal fluctuations. Resting state functional connectivity (RSFC) studies examining child and adolescent psychiatric disorders are being published with increasing frequency, despite concerns about the impact of motion on findings. Here we review important RSFC findings on typical brain development and recent publications of child and adolescent psychiatric disorders. We close with a summary of the major findings and current strengths and limitations of RSFC studies.
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    Differential Effects of Pergolide and Bromocriptine on Working Memory Performance and Brain Activation after Mild Traumatic Brain Injury
    (Liebert, 2020) Flashman, Laura A.; McDonald, Brenna C.; Ford, James C.; Kenny, Rachel M.; Andrews, Katharine D.; Saykin, Andrew J.; McAllister, Thomas W.; Radiology and Imaging Sciences, School of Medicine
    Dopamine D1 and D2 receptors differ with respect to patterns of regional brain distribution and behavioral effects. Pre-clinical work suggests that D1 agonists enhance working memory, but the absence of selective D1 agonists has constrained using this approach in humans. This study examines working memory performance in mild traumatic brain injury (mTBI) patients when given pergolide, a mixed D1/D2 agonist, compared with bromocriptine, a selective D2 agonist. Fifteen individuals were studied 1 month after mTBI and compared with 17 healthy controls. At separate visits, participants were administered 1.25 mg bromocriptine or 0.05 mg pergolide prior to functional magnetic resonance imaging (MRI) using a working memory task (visual-verbal n-back). Results indicated a significant group-by-drug interaction for mean performance across n-back task conditions, where the mTBI group showed better performance on pergolide relative to bromocriptine, whereas controls showed the opposite pattern. There was also a significant effect of diagnosis, where mTBI patients performed worse than controls, particularly while on bromocriptine, as shown in our prior work. Functional MRI activation during the most challenging task condition (3-back > 0-back contrast) showed a significant group-by-drug interaction, with the mTBI group showing increased activation relative to controls in working memory circuitry while on pergolide, including in the left inferior frontal gyrus. Across participants there was a positive correlation between change in activation in this region and change in performance between drug conditions. Results suggest that activation of the D1 receptor may improve working memory performance after mTBI. This has implications for the development of pharmacological strategies to treat cognitive deficits after mTBI.