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 ◽  
...  

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.

1996 ◽  
Vol 35 (03) ◽  
pp. 102-104 ◽  
Author(s):  
E. U. Nitzsche ◽  
J. J. Laubenberger ◽  
Almut Einert ◽  
E. Moser ◽  
G. H. Simon

SummaryMedullary carcinoma of the thyroid gland is a rare tumor. Its prognosis is mainly linked to surgery, because there is no valid alternative therapy to improve patients outcome. In this report, we discuss the recurrence of such a tumor in a 64-year-old female, focusing on magnetic resonance imaging and positron emission tomography evaluation of this tumor.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Sangwoo Kim ◽  
Youngjeon Lee ◽  
Chang-Yeop Jeon ◽  
Yeung Bae Jin ◽  
Sukhoon Oh ◽  
...  

Abstract Background Although the thalamus is known to modulate basal ganglia function related to motor control activity, the abnormal changes within the thalamus during distinct medical complications have been scarcely investigated. In order to explore the feasibility of assessing iron accumulation in the thalamus as an informative biomarker for Parkinson’s disease (PD), this study was designed to employ quantitative susceptibility mapping using a 7 T magnetic resonance imaging system in cynomolgus monkeys. A 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-injected cynomolgus monkey and a healthy control (HC) were examined by 7 T magnetic resonance imaging. Positron emission tomography with 18F-N-(3-fluoro propyl)-2ß-carboxymethoxy-3ß-(4-iodophenyl) nortropane was also employed to identify the relationship between iron deposits and dopamine depletion. All acquired values were averaged within the volume of interest of the nigrostriatal pathway. Findings Compared with the HC, the overall elevation of iron deposition within the thalamus in the Parkinson’s disease model (about 53.81% increase) was similar to that in the substantia nigra (54.81%) region. Substantial susceptibility changes were observed in the intralaminar part of the thalamus (about 70.78% increase). Additionally, we observed that in the Parkinson’s disease model, binding potential values obtained from positron emission tomography were considerably decreased in the thalamus (97.51%) and substantia nigra (92.48%). Conclusions The increased iron deposition in the thalamus showed negative correlation with dopaminergic activity in PD, supporting the idea that iron accumulation affects glutaminergic inputs and dopaminergic neurons. This investigation indicates that the remarkable susceptibility changes in the thalamus could be an initial major diagnostic biomarker for Parkinson’s disease-related motor symptoms.


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