To improve the ecological conditions, the Chinese government adopted six large-scale ecological restoration programs including 'Three-North Shelterbelt Project', "Grain for Green Project" and "Beijing-Tianjin Sand Source Control Project". Meanwhile, these ecologically vulnerable areas have experienced frequent droughts. However, little attention has been paid to the impact of drought on the effectiveness of these programs. Taking Beijing-Tianjin Sand Source Region (BTSSR) as study area, we investigated the role of droughts and ecological restoration program on trends of vegetation activities and to address the question of a possible "drought signal" in assessing effectiveness of ecological restoration program. The results demonstrate the following: (1) Vegetation activity increased in the BTSSR during 2000-2010, with 58.44% of the study area showing an increased NDVI, of which 11.80% had a significant increase at 0.95 confidential level. The decreasing NDVI trends were mainly concentrated in a southwest-to-northeast strip in the study area. (2) Drought was the main driving force for a decreasing trend of vegetation activity in the southwest-to-northeast regions of the BTSSR at the regional and spatial scales. Summer droughts in 2007 and 2009 contributed to the decreasing trend in NDVI. The severe and extreme droughts in summer reduced the NDVI by approximately 13.06% and 23.55%, respectively. (3) The residual analysis result showed that human acitvities, particularly the ecological restoration programs, have a postive impact on vegetation change. Hence, the decreasing trends in the southwest-to-northeast regions of the BTSSR cannot be explained by the improper ecological restoration program and is partly explained by droughts, especially summer droughts. Therefore, drought offset the ecological restoration program-induced increase in vegetation activity in the BTSSR.
The middle insula has been associated with incidental self-processing of negative information elicited by individual's handwriting. However, emotional valence and arousal have been proved to work in an interactive way and located in middle insula. The present functional magnetic resonance imaging study used participant's handwritings as material to explore how incidental self-processing affected the interaction of valence and arousal and its neural basis. Each participant was asked to read silently emotional and neutral words written by himself/herself or the other person. The right middle insula as well as the left putamen showed greater activations in response to emotional stimuli evoking conflicting approach-withdrawal tendencies (i.e., positive high-arousal and negative low-arousal words) relative to stimuli evoking congruent approach versus withdrawal tendencies (i.e., positive low-arousal and negative high-arousal words), whereas a reverse activation pattern in these two regions was observed during processing other-handwriting. The current study indicated that incidental self-processing modulates the interaction of emotional valence and arousal.
Endothelial progenitor cells (EPCs) play important roles in maintaining endothelial integrity and tumor vascularization. However, the differentiation of EPCs in the neoangiogenesis of gliomas has not yet been fully elucidated. The purpose in this study was to investigate the profile of EPC differentiation in rat C6 glioma using magnetic resonance imaging (MRI), a non-invasive monitoring assay. To achieve this goal, we isolated EPCs from rat bone marrow and identified them by detecting CD34, CD133, and VEGFR-2, the markers of EPCs. Coexpression of Ac-LDL and UEA-1 in EPCs was also determined. To dynamically monitor the migration of circulating cells, the EPCs were labeled with ultrasmall superparamagnetic iron oxide (USPIO) and injected by tail vein into rats bearing C6 glioma. MRI was performed at 24, 48, and 96 h after injection. The distribution and differentiation of EPCs were confirmed by histology. We found that the USPIO-labeled EPCs appeared at the tumor periphery where a large number of CD105-positive cells appeared at 24 h after injection by using MRI scanning. Ninety-six hours after injection, immunohistochemistry and Prussian blue staining were used to observe the labeled EPCs in the tumor tissue. We found that many of the labeled EPCs were overlapped with VEGFR-2-positive endothelial cells, but not CD105- or CD34-positive cells. These results suggest that EPCs can cross the blood-brain barrier from peripheral blood and home to tumors, where they differentiate into endothelial cells, including VEGFR-2-positive endothelial cells. MRI is a useful method for dynamically tracking the migration of USPIO-labeled EPCs.
Large echo spacing of unipolar readout gradients in current multi-echo gradient-echo (GRE) sequences for mapping fields in quantitative susceptibility mapping (QSM) can be reduced using bipolar readout gradients thereby improving acquisition efficiency.
Reduced neural activation have been consistently observed during repeated items processing, a phenomenon termed repetition suppression. The present study used functional magnetic resonance imaging (fMRI) to investigate whether and how stimuli of emotional valence affects repetition suppression by adopting Chinese personality-trait words as materials. Seventeen participants were required to read the negative and neutral Chinese personality-trait words silently. And then they were presented with repeated and novel items during scanning. Results showed significant repetition suppression in the inferior occipital gyrus only for neutral personality-trait words, whereas similar repetition suppression in the left inferior temporal gyrus and left middle temporal gyrus was revealed for both the word types. These results indicated common and distinct neural substrates during processing Chinese repeated negative and neutral personality-trait words.
Past researches showed that empathy for pain not only triggers a resonance mechanism between other and self, but also is modulated by contextual factors. Using functional magnetic resonance imaging, the present study demonstrated that short-term media violence exposure reduced both pain ratings and also the activation of anterior insula and anterior mid-cingulate cortex to others pain. Thus, violence exposure modulated empathic responses to others pain based on a physiological desensitization.
Unfairness plays an important role in economic decision making. This fMRI study sought to investigate how the loss and the gain contexts could modulate behavioral and brain responses to unfairness by focusing on participants rejection behaviors during an Ultimatum Game paradigm. Participants were scanned while they were playing the Ultimatum Game as responders in both loss and gain contexts, i.e. receiving ¥50 as gains and paying for ¥50 as losses. At the behavioral level, lower fairness ratings and higher rejection rates were revealed for unfair losses than unfair gains. At the neural level, left dorsolateral prefrontal cortex, bilateral anterior insula, anterior cingulate cortex/anterior middle cingulate cortex and bilateral dorsal striatum were associated with rejection (vs. acceptance) in the loss context, but not in the gain context. Together, our data indicated that participants may experience more unfairness in UG and stronger desire to sanction social norm violations in the loss context than in the gain context, inducing more fairness-related neutral activities when rejecting (vs. accepting) unfair losses than unfair gains. These findings shed light on the significance of context (i.e. loss or gain) in fairness-related social decision-making processes.
The self has long been regarded as a unique cognitive structure by virtue of its superior mnemonic abilities. Two separate effects result from this self memory facilitation: self-reference effect and self-descriptiveness effect in memory. Self-reference effect denotes that information processed with reference to the self is better remembered than information processed with reference to others, whereas self-descriptiveness effect indicates that items judged to be self-relevant is remembered better than items judged not to be relevant to self during self-reference task. Although there is a compelling connection between self-reference effect in memory and self mentalization processes indexed by the medial prefrontal activity, the underlying mechanisms of the self-descriptiveness effect in memory have remained underspecified. In the present fMRI study, we used a subsequent memory paradigm to examine the neural correlates of self-descriptiveness and self-reference effect in memory. Participants encoded personality traits while performing self-reference and other-reference task (judged the descriptiveness of the traits to themselves or a famous person "Bruce Lee"), and then were given a test of recognition memory outside the scanner. It is revealed that the hippocampal activity corresponded with self-descriptiveness effect in memory, but the activity of the medial prefrontal cortex and perirhinal cortex related to self-reference effect in memory. These findings suggested that the memory boost for self-relevant items relies on the enhanced relational binding mechanisms employed during self-relevant items.
Human empathy is not merely a resonance with others physical condition, but is modulated by social factors. Using functional magnetic resonance imaging, the present study demonstrated an increased brain empathic response to others in pain when they received no rather than a large reward, with increments of the ACC, aMCC, insula and postcentral gyrus in the pain matrix and temporoparietal junction. Thus, pain targets financial situation modulated brain empathic responses in the pain matrix based on an understanding of the situation pain target faces.
This study demonstrates the dependence of non-local susceptibility effects on object orientation in gradient echo MRI and the reduction of non-local effects by deconvolution using quantitative susceptibility mapping. Imaging experiments were performed on a 3T MRI system using a spoiled 3D multi-echo GRE sequence on phantoms of known susceptibilities, and on human brains of healthy subjects and patients with intracerebral hemorrhages. Magnetic field measurements were determined from multiple echo phase data. To determine the quantitative susceptibility mapping, these field measurements were deconvolved through a dipole inversion kernel under a constraint of consistency with the magnitude images. Phantom and human data demonstrated that the hypointense region in GRE magnitude image corresponding to a susceptibility source increased in volume with TE and varied with the source orientation. The induced magnetic field extended beyond the susceptibility source and varied with its orientation. In quantitative susceptibility mapping, these blooming artifacts, including their dependence on object orientation, were reduced, and the material susceptibilities were quantified.
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