NeuroImage
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Simultaneously acquiring functional Near Infrared Spectroscopy (fNIRS) during Transcranial Magnetic Stimulation (rTMS) offers the possibility of directly investigating superficial cortical brain activation and connectivity. In addition, the effects of rTMS in distinct brain regions without quantifiable behavioral changes can be objectively measured. ⋯ Simultaneous rTMS/fNIRS provides a reliable measure of regional cortical brain activation and connectivity that could be very useful in studying brain disorders as well as cortical changes induced by rTMS.
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Both affective neuroscience and decision science focus on the role of emotions in decisions. Regret and disappointment are emotions experienced with negative decision outcomes. The present research examines the neural substrates of regret and disappointment as well as the role of regret and disappointment in decision making. ⋯ Both regret and disappointment activated anterior insula and dorsomedial prefrontal cortex relative to fixation, with greater activation in regret than in disappointment. In contrast to disappointment, regret also showed enhanced activation in the lateral orbitofrontal cortex. These findings suggest that regret and disappointment, emotions experienced during decision-related loss, share a general neural network but differ in both the magnitude of subjective feelings and with regret activating some regions with greater intensity.
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The objective of this study was to investigate total volume and spatial distribution of white matter hyperintensities (WMH) in a large sample of newly diagnosed Parkinson's disease (PD) patients with and without mild cognitive impairment (MCI) compared to normal controls (NC). Furthermore, we aimed to examine the impact of the WMH on attention-executive performance in PD. MCI is regarded as a pre-dementia stage. ⋯ Analysis showed that there were no significant differences between the 3 groups in total volume or spatial distribution of WMH. In addition there was no significant relationship between total volume or spatial distribution of WMH and attention-executive functions in PD. We conclude that in this PD cohort, cognitive impairment seems to be independent of WMH damage.
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Due to its crucial role for memory processes and its relevance in neurological and psychiatric disorders, the hippocampus has been the focus of neuroimaging research for several decades. In vivo measurement of human hippocampal volume and shape with magnetic resonance imaging has become an important element of neuroimaging research. Nevertheless, volumetric findings are still inconsistent and controversial for many psychiatric conditions including affective disorders. ⋯ These are major sources of variance between different protocols. In contrast, the definitions of the lateral, superior, and inferior borders are less disputed. Directing resources to replication studies that incorporate characteristics of the segmentation protocols presented herein may help resolve seemingly contradictory volumetric results between prior neuroimaging studies and facilitate the appropriate selection of protocols for manual or automated delineation of the hippocampus for future research purposes.
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Comparative Study
Direct quantitative comparison between cross-relaxation imaging and diffusion tensor imaging of the human brain at 3.0 T.
Cross-relaxation imaging (CRI) describes the magnetization transfer within tissues between mobile water protons and macromolecular protons. Whole-brain parametric maps of the principle kinetic components of magnetization transfer, the fraction of macromolecular protons (f) and the rate constant (k), revealed detailed anatomy of white matter (WM) fiber tracts at 1.5 T. In this study, CRI was first adapted to 3.0 T, and constraints for transverse relaxation times of water and macromolecular protons were identified to enable unbiased f and k estimation. ⋯ The lack of association between CRI and FA in WM is consistent with differences in the underlying physical principles between techniques - fiber density vs. directionality, respectively. The association in GM may be attributable to variable axonal density unique to each structure. Our findings suggest that whole-brain CRI provides distinct quantitative information compared to DTI, and CRI parameters may prove constructive as biomarkers in neurological diseases.