scholarly journals Metabolic Connectivity as Index of Verbal Working Memory

2015 ◽  
Vol 35 (7) ◽  
pp. 1122-1126 ◽  
Author(s):  
Na Zou ◽  
Gael Chetelat ◽  
Mustafa G Baydogan ◽  
Jing Li ◽  
Florian U Fischer ◽  
...  
Keyword(s):  
Working Memory ◽  
Resting State ◽  
Verbal Working Memory ◽  
Covariance Estimation ◽  
Emission Tomography ◽  
Group Level ◽  
Positron Emission ◽  
Brodmann Areas ◽  
Metabolic Connectivity ◽  
Sparse Inverse Covariance Estimation

Positron emission tomography (PET) data are commonly analyzed in terms of regional intensity, while covariant information is not taken into account. Here, we searched for network correlates of healthy cognitive function in resting state PET data. PET with [18F]-fluorodeoxyglucose and a test of verbal working memory (WM) were administered to 35 young healthy adults. Metabolic connectivity was modeled at a group level using sparse inverse covariance estimation. Among 13 WM-relevant Brodmann areas (BAs), 6 appeared to be robustly connected. Connectivity within this network was significantly stronger in subjects with above-median WM performance. In respect to regional intensity, i.e., metabolism, no difference between groups was found. The results encourage examination of covariant patterns in FDG-PET data from non-neurodegenerative populations.

Verbal working memory and solvent exposure: A positron emission tomography study.

2000 ◽  
Vol 14 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Marc W. Haut ◽  
Sharon Leach ◽  
Hiroto Kuwabara ◽  
Shannon Whyte ◽  
Ty Callahan ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Working Memory ◽  
Verbal Working Memory ◽  
Emission Tomography ◽  
Positron Emission Tomography Study ◽  
Solvent Exposure ◽  
Positron Emission

Dissociation of Storage and Rehearsal in Verbal Working Memory: Evidence From Positron Emission Tomography

1996 ◽  
Vol 7 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Edward Awh ◽  
John Jonides ◽  
Edward E. Smith ◽  
Eric H. Schumacher ◽  
Robert A. Koeppe ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Working Memory ◽  
Memory Task ◽  
Recognition Task ◽  
Verbal Working Memory ◽  
Brain Regions ◽  
Emission Tomography ◽  
Positron Emission ◽  
Rehearsal Strategy ◽  
Phonological Store

Current cognitive models of verbal working memory include two components a phonological store and a rehearsal mechanism that refreshes the contents of this store We present research using positron emission tomography (PET) to provide further evidence for this functional division In Experiment 1, subjects performed a variant of Sternberg's (1966) item recognition task Experiment 2 used a continuous memory task with control conditions designed to separate the brain regions underlying storage and rehearsal The results show that independent brain regions mediate storage and rehearsal In Experiment 3, a dual-task procedure supported the assumption that these memory tasks elicited a rehearsal strategy

scholarly journals Oxygen Extraction Fraction at Maximally Vasodilated Tissue in the Ischemic Brain Estimated from the Regional CO2 Responsiveness Measured by Positron Emission Tomography

1988 ◽  
Vol 8 (2) ◽  
pp. 227-235 ◽  
Author(s):  
Iwao Kanno ◽  
Kazuo Uemura ◽  
Schuichi Higano ◽  
Matsutaro Murakami ◽  
Hidehiro Iida ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Resting State ◽  
Emission Tomography ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cross Point ◽  
Steady State Method ◽  
Extraction Fraction ◽  
Positron Emission ◽  
Vascular Responsiveness

The oxygen extraction fraction (OEF) at maximally vasodilated tissue in patients with chronic cerebrovascular disease was evaluated using positron emission tomography. The vascular responsiveness to changes in PaCO2 was measured by the H215O autoradiographic method. It was correlated with the resting-state OEF, as estimated using the 15O steady-state method. The subjects comprised 15 patients with unilateral or bilateral occlusion and stenosis of the internal carotid artery or middle cerebral artery or moyamoya disease. In hypercapnia, the scattergram between the OEF and the vascular responsiveness to changes in PaCO2 revealed a significant negative correlation in 11 of 19 studies on these patients, and the OEF at the zero cross point of the regression line with a vascular responsiveness of 0 was 0.53 ± 0.08 (n = 11). This OEF in the resting state corresponds to exhaustion of the capacity for vasodilation. The vasodilatory capacity is discussed in relation to the lower limit of autoregulation.

scholarly journals Behavioral Activation and the Variability of Cerebral Glucose Metabolic Measurements

1987 ◽  
Vol 7 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Ranjan Duara ◽  
Karen Gross-Glenn ◽  
Warren W. Barker ◽  
Jen Yueh Chang ◽  
Anthony Apicella ◽  
...  
Keyword(s):  
Resting State ◽  
Brain Metabolism ◽  
Behavioral Activation ◽  
Emission Tomography ◽  
Positron Emission ◽  
Activated State ◽  
Subject Variability ◽  
Within Subjects ◽  
Picture Viewing ◽  
Within Subject Variability

Variability in cerebral glucose metabolism was examined between and within subjects when paired studies were performed in the resting state or in a behaviorally activated state. Both normal and demented subjects were studied twice each, from 1 to 6 weeks apart, under near-identical conditions, using positron emission tomography (PET) and [18F]fluorodeoxyglucose. Resting state studies were repeated in nine normal and four demented subjects. A picture-viewing test, used for activation during PET, was used repeatedly in seven normal and five demented subjects. Within-subject variability, as assessed by the percent difference in metabolic rates in paired studies, was reduced by 60–70% for activation state compared to resting state studies in normals. It is concluded that PET studies of brain metabolism, which are designed to study the active brain, should indeed be performed in functionally activated states, as in addition to demonstrating metabolism during a defined functional state, activation studies show reduced variability of cerebral metabolic measures.

scholarly journals Dopamine D1 signaling organizes network dynamics underlying working memory

2016 ◽  
Vol 2 (6) ◽  
pp. e1501672 ◽  
Author(s):  
Joshua L. Roffman ◽  
Alexandra S. Tanner ◽  
Hamdi Eryilmaz ◽  
Anais Rodriguez-Thompson ◽  
Noah J. Silverstein ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Working Memory ◽  
Network Effects ◽  
Pyramidal Neurons ◽  
Emission Tomography ◽  
Cognitive Resources ◽  
Resonance Imaging ◽  
Positron Emission ◽  
Dopamine Signaling ◽  
Opposing Effects

Local prefrontal dopamine signaling supports working memory by tuning pyramidal neurons to task-relevant stimuli. Enabled by simultaneous positron emission tomography–magnetic resonance imaging (PET-MRI), we determined whether neuromodulatory effects of dopamine scale to the level of cortical networks and coordinate their interplay during working memory. Among network territories, mean cortical D1 receptor densities differed substantially but were strongly interrelated, suggesting cross-network regulation. Indeed, mean cortical D1 density predicted working memory–emergent decoupling of the frontoparietal and default networks, which respectively manage task-related and internal stimuli. In contrast, striatal D1 predicted opposing effects within these two networks but no between-network effects. These findings specifically link cortical dopamine signaling to network crosstalk that redirects cognitive resources to working memory, echoing neuromodulatory effects of D1 signaling on the level of cortical microcircuits.

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