Human brain mapping
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Human brain mapping · Sep 2015
Independent component analysis of functional networks for response inhibition: Inter-subject variation in stop signal reaction time.
Cognitive control is a critical executive function. Many studies have combined general linear modeling and the stop signal task (SST) to delineate the component processes of cognitive control. For instance, by contrasting stop success (SS) and stop error (SE) trials in the SST, investigators examined regional responses to stop signal inhibition. ⋯ These findings suggest that motor preparation and execution prolongs the SSRT, likely via an interaction between the go and stop processes as suggested by the race model. Behaviorally, consistent with this hypothesis, the difference in G and SE reaction times is positively correlated with SSRT across subjects. These new results highlight the importance of cognitive motor regions in response inhibition and support the utility of ICA in uncovering functional networks for cognitive control in the SST.
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Human brain mapping · Sep 2015
Multicenter StudyLongitudinal reproducibility of automatically segmented hippocampal subfields: A multisite European 3T study on healthy elderly.
Recently, there has been an increased interest in the use of automatically segmented subfields of the human hippocampal formation derived from magnetic resonance imaging (MRI). However, little is known about the test-retest reproducibility of such measures, particularly in the context of multisite studies. Here, we report the reproducibility of automated Freesurfer hippocampal subfields segmentations in 65 healthy elderly enrolled in a consortium of 13 3T MRI sites (five subjects per site). ⋯ Despite considerable differences of MRI scanner configurations, we found consistent hippocampal subfields volumes estimation. CA2-3, CA4-DG, and sub-CA1 (subiculum, presubiculum, and CA1 pooled together) gave test-retest reproducibility similar to the whole hippocampus. Our findings suggest that the larger hippocampal subfields volume may be reliable longitudinal markers in multisite studies.
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Human brain mapping · Aug 2015
Neural circuitry underlying effects of context on human pain-related fear extinction in a renewal paradigm.
The role of context in pain-related extinction learning remains poorly understood. We analyzed the neural mechanisms underlying context-dependent extinction and renewal in a clinically relevant model of conditioned abdominal pain-related fear. ⋯ The extinction context affects the neural processing of nonpain predictive safety cues, supporting a role of safety learning in pain-related memory processes.
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Although diffusion tensor imaging (DTI) and postmortem dissections improved the knowledge of white matter (WM) anatomy, functional information is lacking. Our aims are: to provide a subcortical atlas of human brain functions; to elucidate the functional roles of different bundles; to provide a probabilistic resection map of WM. ⋯ We report the first anatomo-functional atlas of WM connectivity in humans by correlating cognitive data, electrostimulation, and DTI. We provide a valuable tool for cognitive neurosciences and clinical applications.
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To identify overlapping and unique grey (GM) and white matter (WM) signatures within the frontotemporal lobar degeneration (FTLD) continuum, and discriminate likely FTLD-TAU and FTLD-TDP patients using structural and diffusion tensor (DT) magnetic resonance imaging (MRI). ⋯ In the FTLD spectrum, WM disruption is more severe than GM damage. Frontal cortex and WM pathways represent the common target of neurodegeneration in these conditions. The topographic pattern of damage supports a "prion-like" protein propagation through WM connections as underlying mechanism of the stereotyped progression of FTLD.