The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Ronald M Harper - One of the best experts on this subject based on the ideXlab platform.
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accelerated echo planer j resolved spectroscopic imaging of Putamen and thalamus in obstructive sleep apnea
Scientific Reports, 2016Co-Authors: Manoj K Sarma, Paul M Macey, Rajakumar Nagarajan, Ravi Aysola, Ronald M Harper, Albert M ThomasAbstract:Obstructive sleep apnea syndrome (OSAS) leads to neurocognitive and autonomic deficits that are partially mediated by thalamic and Putamen pathology. We examined the underlying neurochemistry of those structures using compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (JRESI), and quantified values with prior knowledge fitting. Bilaterally increased thalamic mI/Cr, Putamen Glx/Cr, and Glu/Cr, and bilaterally decreased thalamic and Putamen tCho/Cr and GABA/Cr occurred in OSAS vs healthy subjects (p < 0.05). Increased right thalamic Glx/Cr, Glu/Cr, Gln/Cr, Asc/Cr, and decreased GPC/Cr and decreased left thalamic tNAA/Cr, NAA/Cr were detected. The right Putamen showed increased mI/Cr and decreased tCho/Cr, and the left, decreased PE/Cr ratio. ROC curve analyses demonstrated 60–100% sensitivity and specificity for the metabolite ratios in differentiating OSAS vs. controls. Positive correlations were found between: left thalamus mI/Cr and baseline oxygen saturation (SaO2); right Putamen tCho/Cr and apnea hypopnea index; right Putamen GABA/Cr and baseline SaO2; left Putamen PE/Cr and baseline SaO2; and left Putamen NAA/Cr and SaO2 nadir (all p < 0.05). Negative correlations were found between left Putamen PE/Cr and SaO2 nadir. These findings suggest underlying inflammation or glial activation, with greater alterations accompanying lower oxygen saturation. These metabolite levels may provide biomarkers for future neurochemical interventions by pharmacologic or other means.
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Accelerated Echo Planer J-resolved Spectroscopic Imaging of Putamen and Thalamus in Obstructive Sleep Apnea.
Scientific Reports, 2016Co-Authors: Manoj K Sarma, Paul M Macey, Rajakumar Nagarajan, Ravi Aysola, Ronald M Harper, M. Albert ThomasAbstract:Obstructive sleep apnea syndrome (OSAS) leads to neurocognitive and autonomic deficits that are partially mediated by thalamic and Putamen pathology. We examined the underlying neurochemistry of those structures using compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (JRESI), and quantified values with prior knowledge fitting. Bilaterally increased thalamic mI/Cr, Putamen Glx/Cr, and Glu/Cr, and bilaterally decreased thalamic and Putamen tCho/Cr and GABA/Cr occurred in OSAS vs healthy subjects (p
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brain Putamen volume changes in newly diagnosed patients with obstructive sleep apnea
NeuroImage: Clinical, 2014Co-Authors: Rajesh Kumar, Paul M Macey, Salar Farahvar, Jennifer A Ogren, Paul M Thompson, Frisca L Yango, Ronald M HarperAbstract:Obstructive sleep apnea (OSA) is accompanied by cognitive, motor, autonomic, learning, and affective abnormalities. The Putamen serves several of these functions, especially motor and autonomic behaviors, but whether global and specific sub-regions of that structure are damaged is unclear. We assessed global and regional Putamen volumes in 43 recently-diagnosed, treatment-naive OSA (age, 46.4 ± 8.8 years; 31 male) and 61 control subjects (47.6 ± 8.8 years; 39 male) using high-resolution T1-weighted images collected with a 3.0-Tesla MRI scanner. Global Putamen volumes were calculated, and group differences evaluated with independent samples t-tests, as well as with analysis of covariance (covariates; age, gender, and total intracranial volume). Regional differences between groups were visualized with 3D surface morphometry-based group ratio maps. OSA subjects showed significantly higher global Putamen volumes, relative to controls. Regional analyses showed Putamen areas with increased and decreased tissue volumes in OSA relative to control subjects, including increases in caudal, mid-dorsal, mid-ventral portions, and ventral regions, while areas with decreased volumes appeared in rostral, mid-dorsal, medial-caudal, and mid-ventral sites. Global Putamen volumes were significantly higher in the OSA subjects, but local sites showed both higher and lower volumes. The appearance of localized volume alterations points to differential hypoxic or perfusion action on glia and other tissues within the structure, and may reflect a stage in progression of injury in these newly-diagnosed patients toward the overall volume loss found in patients with chronic OSA. The regional changes may underlie some of the specific deficits in motor, autonomic, and neuropsychologic functions in OSA.
Mustafa M Husain - One of the best experts on this subject based on the ideXlab platform.
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a magnetic resonance imaging study of Putamen nuclei in major depression
Psychiatry Research-neuroimaging, 1991Co-Authors: Orest B Boyko, William M. Mcdonald, Mustafa M Husain, Murali P Doraiswamy, Gary S Figiel, Chul Na, Rodrigo P Escalona, Charles B Nemeroff, Ranga Rama K KrishnanAbstract:Abstract The basal ganglia are recognized as putative mediators of certain cognitive and behavioral symptoms of major depression. Moreover, patients with basal ganglia lesions have repeatedly exhibited significant affective symptomatology, including apathy, depressive mood, and psychosis. Using high resolution, axial T2 intermediate magnetic resonance images, and a systematic sampling stereologic method, we assessed Putamen nuclei volumes in 41 patients with major depression (DSM-III) and 44 healthy volunteer controls of similar age. Depressed patients had significantly smaller Putamen nuclei compared with controls. Age was negatively correlated with Putamen size in both groups. These results are the first demonstration of diminished Putamen volumes in depression and further support a role for basal ganglia structures in the etiopathogenesis of depression.
Paul M Macey - One of the best experts on this subject based on the ideXlab platform.
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accelerated echo planer j resolved spectroscopic imaging of Putamen and thalamus in obstructive sleep apnea
Scientific Reports, 2016Co-Authors: Manoj K Sarma, Paul M Macey, Rajakumar Nagarajan, Ravi Aysola, Ronald M Harper, Albert M ThomasAbstract:Obstructive sleep apnea syndrome (OSAS) leads to neurocognitive and autonomic deficits that are partially mediated by thalamic and Putamen pathology. We examined the underlying neurochemistry of those structures using compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (JRESI), and quantified values with prior knowledge fitting. Bilaterally increased thalamic mI/Cr, Putamen Glx/Cr, and Glu/Cr, and bilaterally decreased thalamic and Putamen tCho/Cr and GABA/Cr occurred in OSAS vs healthy subjects (p < 0.05). Increased right thalamic Glx/Cr, Glu/Cr, Gln/Cr, Asc/Cr, and decreased GPC/Cr and decreased left thalamic tNAA/Cr, NAA/Cr were detected. The right Putamen showed increased mI/Cr and decreased tCho/Cr, and the left, decreased PE/Cr ratio. ROC curve analyses demonstrated 60–100% sensitivity and specificity for the metabolite ratios in differentiating OSAS vs. controls. Positive correlations were found between: left thalamus mI/Cr and baseline oxygen saturation (SaO2); right Putamen tCho/Cr and apnea hypopnea index; right Putamen GABA/Cr and baseline SaO2; left Putamen PE/Cr and baseline SaO2; and left Putamen NAA/Cr and SaO2 nadir (all p < 0.05). Negative correlations were found between left Putamen PE/Cr and SaO2 nadir. These findings suggest underlying inflammation or glial activation, with greater alterations accompanying lower oxygen saturation. These metabolite levels may provide biomarkers for future neurochemical interventions by pharmacologic or other means.
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Accelerated Echo Planer J-resolved Spectroscopic Imaging of Putamen and Thalamus in Obstructive Sleep Apnea.
Scientific Reports, 2016Co-Authors: Manoj K Sarma, Paul M Macey, Rajakumar Nagarajan, Ravi Aysola, Ronald M Harper, M. Albert ThomasAbstract:Obstructive sleep apnea syndrome (OSAS) leads to neurocognitive and autonomic deficits that are partially mediated by thalamic and Putamen pathology. We examined the underlying neurochemistry of those structures using compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (JRESI), and quantified values with prior knowledge fitting. Bilaterally increased thalamic mI/Cr, Putamen Glx/Cr, and Glu/Cr, and bilaterally decreased thalamic and Putamen tCho/Cr and GABA/Cr occurred in OSAS vs healthy subjects (p
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brain Putamen volume changes in newly diagnosed patients with obstructive sleep apnea
NeuroImage: Clinical, 2014Co-Authors: Rajesh Kumar, Paul M Macey, Salar Farahvar, Jennifer A Ogren, Paul M Thompson, Frisca L Yango, Ronald M HarperAbstract:Obstructive sleep apnea (OSA) is accompanied by cognitive, motor, autonomic, learning, and affective abnormalities. The Putamen serves several of these functions, especially motor and autonomic behaviors, but whether global and specific sub-regions of that structure are damaged is unclear. We assessed global and regional Putamen volumes in 43 recently-diagnosed, treatment-naive OSA (age, 46.4 ± 8.8 years; 31 male) and 61 control subjects (47.6 ± 8.8 years; 39 male) using high-resolution T1-weighted images collected with a 3.0-Tesla MRI scanner. Global Putamen volumes were calculated, and group differences evaluated with independent samples t-tests, as well as with analysis of covariance (covariates; age, gender, and total intracranial volume). Regional differences between groups were visualized with 3D surface morphometry-based group ratio maps. OSA subjects showed significantly higher global Putamen volumes, relative to controls. Regional analyses showed Putamen areas with increased and decreased tissue volumes in OSA relative to control subjects, including increases in caudal, mid-dorsal, mid-ventral portions, and ventral regions, while areas with decreased volumes appeared in rostral, mid-dorsal, medial-caudal, and mid-ventral sites. Global Putamen volumes were significantly higher in the OSA subjects, but local sites showed both higher and lower volumes. The appearance of localized volume alterations points to differential hypoxic or perfusion action on glia and other tissues within the structure, and may reflect a stage in progression of injury in these newly-diagnosed patients toward the overall volume loss found in patients with chronic OSA. The regional changes may underlie some of the specific deficits in motor, autonomic, and neuropsychologic functions in OSA.
Angela C Roberts - One of the best experts on this subject based on the ideXlab platform.
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selective role of the Putamen in serial reversal learning in the marmoset
Cerebral Cortex, 2019Co-Authors: Stacey A W Jackson, Nicole K Horst, Sebastian F A Axelsson, Naotaka Horiguchi, Gemma J Cockcroft, Trevor W Robbins, Angela C RobertsAbstract:: Fronto-striatal circuitry involving the orbitofrontal cortex has been identified as mediating successful reversal of stimulus-outcome contingencies. The region of the striatum that most contributes to reversal learning remains unclear, with studies in primates implicating both caudate nucleus and Putamen. We trained four marmosets on a touchscreen-based serial reversal task and implanted each with cannulae targeting both Putamen and caudate bilaterally. This allowed reversible inactivation of the two areas within the same monkeys, but across separate sessions, to directly investigate their respective contributions to reversal performance. Behavioral sensitivity to the GABAA agonist muscimol varied across subjects and between brain regions, so each marmoset received a range of doses. Intermediate doses of intra-Putamen muscimol selectively impaired reversal performance, leaving the baseline discrimination phase unchanged. There was no effect of low doses and high doses were generally disruptive. By contrast, low doses of intra-caudate muscimol improved reversal performance, while high doses impaired both reversal and baseline discrimination performance. These data provide evidence for a specific role of the Putamen in serial reversal learning, which may reflect the more habitual nature of repeated reversals using the same stimulus pair.
Albert M Thomas - One of the best experts on this subject based on the ideXlab platform.
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accelerated echo planer j resolved spectroscopic imaging of Putamen and thalamus in obstructive sleep apnea
Scientific Reports, 2016Co-Authors: Manoj K Sarma, Paul M Macey, Rajakumar Nagarajan, Ravi Aysola, Ronald M Harper, Albert M ThomasAbstract:Obstructive sleep apnea syndrome (OSAS) leads to neurocognitive and autonomic deficits that are partially mediated by thalamic and Putamen pathology. We examined the underlying neurochemistry of those structures using compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (JRESI), and quantified values with prior knowledge fitting. Bilaterally increased thalamic mI/Cr, Putamen Glx/Cr, and Glu/Cr, and bilaterally decreased thalamic and Putamen tCho/Cr and GABA/Cr occurred in OSAS vs healthy subjects (p < 0.05). Increased right thalamic Glx/Cr, Glu/Cr, Gln/Cr, Asc/Cr, and decreased GPC/Cr and decreased left thalamic tNAA/Cr, NAA/Cr were detected. The right Putamen showed increased mI/Cr and decreased tCho/Cr, and the left, decreased PE/Cr ratio. ROC curve analyses demonstrated 60–100% sensitivity and specificity for the metabolite ratios in differentiating OSAS vs. controls. Positive correlations were found between: left thalamus mI/Cr and baseline oxygen saturation (SaO2); right Putamen tCho/Cr and apnea hypopnea index; right Putamen GABA/Cr and baseline SaO2; left Putamen PE/Cr and baseline SaO2; and left Putamen NAA/Cr and SaO2 nadir (all p < 0.05). Negative correlations were found between left Putamen PE/Cr and SaO2 nadir. These findings suggest underlying inflammation or glial activation, with greater alterations accompanying lower oxygen saturation. These metabolite levels may provide biomarkers for future neurochemical interventions by pharmacologic or other means.
