NeuroImage
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This study demonstrates that infants who are born prematurely and who have experienced at least 40days of intensive or special care have increased brain neuronal responses to noxious stimuli compared to healthy newborns at the same postmenstrual age. We have measured evoked potentials generated by noxious clinically-essential heel lances in infants born at term (8 infants; born 37-40weeks) and in infants born prematurely (7 infants; born 24-32weeks) who had reached the same postmenstrual age (mean age at time of heel lance 39.2+/-1.2weeks). ⋯ This enhancement is not associated with specific brain lesions but reflects a functional change in pain processing in the brain that is likely to underlie previously reported changes in pain sensitivity in older ex-preterm children. Our ability to quantify and measure experience-dependent changes in infant cortical pain processing will allow us to develop a more rational approach to pain management in neonatal intensive care.
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Beta amyloid plaques, neurofibrillary tangles, and impaired glucose metabolism are among the most prevalent pathological characteristics of Alzheimer's disease (AD). However, separate visualization of these three AD-related pathologies in living humans has not been conducted. Here, we show that positron emission tomography (PET) imaging using the three radiotracers (11)C-Pittsburgh compound B (PIB), 2-(1-{6-[(2-(18)F-fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene) malononitrile (FDDNP), and 2-[18F]fluoro-2-deoxy-d-glucose (FDG), in the same subjects, with and without AD, can provide valuable information on the pathological patterns of the distribution of tracers for amyloid plaque, neurofibrillary tangle, and glucose hypometabolism in AD. ⋯ We found that the hippocampal formation was the most significant brain region in the voxel mapping of FDDNP minus PIB in the same patients with AD. Voxel-based analysis of FDG-PET in the same subjects revealed that brain regions with glucose hypometabolism in patients with AD overlap with regions of high PIB binding. In conclusion, PET imaging using these three radiotracers in the same subjects may contribute toward developing and testing disease-modifying drugs targeting amyloid pathology, tau pathology, and/or energy metabolism.
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Compared to standard spoiled gradient echo (SPGR)-methods, balanced steady-state free precession (bSSFP) provides quantitative magnetization transfer (qMT) images with increased resolution and high signal-to-noise ratio (SNR) in clinically feasible acquisition times. The aim of this study was to acquire 3D high-resolution qMT-data to create standardized qMT-values of many single brain structures that might serve as a baseline for the future characterization of pathologies of the brain. QMT parameters, such as the fractional pool size (F), exchange rate (kf) and relaxation times of the free pool (T1, T2) were assessed in a total of 12 white matter (WM) and 11 grey matter (GM) structures in 12 healthy volunteers with MT-sensitized bSSFP. ⋯ The observed differences from previous studies can partly be explained by the reduced partial volume effects. MT-sensitized bSSFP is an ideal candidate for qMT-analysis in the clinical routine as it provides high-resolution 3D qMT-data of even small brain structures in clinically feasible acquisition times. The present qMT-data can serve as a reference for the characterization of cerebral diseases.
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Task switching requires executive control processes that undergo age-related decline. Previous neuroimaging studies have identified age-related differences in brain activation associated with global switching effects (dual-task blocks versus single-task blocks), but age-related differences in activation during local switching effects (switch trials versus repeat trials, within blocks) have not been investigated. This experiment used functional magnetic resonance imaging (fMRI), and diffusion tensor imaging (DTI), to examine adult age differences in task switching across adjacent trials (i.e., local task switching). ⋯ Further, individual differences in cue-related functional connectivity shared a substantial portion of the age-related variability in the efficiency of target categorization response (drift rate). This age-related difference in functional connectivity, however, was independent of white matter integrity within task-relevant regions. These findings highlight the functional connectivity of frontoparietal activation as a potential source of age-related decline in executive control.
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In most cases, object recognition is related to the matching of internal memory contents and bottom-up external sensory stimulation. The aim of this study was to investigate the electrophysiological correlates of memory matching based on EEG oscillatory phase synchronization analysis. ⋯ When memory representation and visual information match, phase-synchronization is stronger in the right hemisphere; conversely, when they do not match, stronger phase synchronization is observed in the left hemisphere. The present results reveal the integrative role of oscillatory activity in the memory matching process.