53 research outputs found
Spatial patterns of genome‐wide expression profiles reflect anatomic and fiber connectivity architecture of healthy human brain
No full textUnraveling the relationship between molecular signatures in the brain and their functional, architectonic, and anatomic correlates is an important neuroscientific goal. It is still not well understood whether the diversity demonstrated by histological studies in the human brain is reflected in the spatial patterning of whole brain transcriptional profiles. Using genome-wide maps of transcriptional distribution of the human brain by the Allen Brain Institute, we test the hypothesis that gene expression profiles are specific to anatomically described brain regions. In this work, we demonstrate that this is indeed the case by showing that gene similarity clusters appear to respect conventional basal-cortical and caudal-rostral gradients. To fully investigate the causes of this observed spatial clustering, we test a connectionist hypothesis that states that the spatial patterning of gene expression in the brain is simply reflective of the fiber tract connectivity between brain regions. We find that although gene expression and structural connectivity are not determined by each other, they do influence each other with a high statistical significance. This implies that spatial diversity of gene expressions is a result of mainly location-specific features but is influenced by neuronal connectivity, such that like cellular species preferentially connects with like cells
Connectivity, not region-intrinsic properties, predicts regional vulnerability to progressive tau pathology in mouse models of disease
No full textAbstract Spatiotemporal tau pathology progression is regarded as highly stereotyped within each type of degenerative condition. For instance, AD has a progression of tau pathology consistently beginning in the entorhinal cortex, the locus coeruleus, and other nearby noradrenergic brainstem nuclei, before spreading to the rest of the limbic system as well as the cingulate and retrosplenial cortices. Proposed explanations for the consistent spatial patterns of tau pathology progression, as well as for why certain regions are selectively vulnerable to exhibiting pathology over the course of disease generally focus on transsynaptic spread proceeding via the brain’s anatomic connectivity network in a cell-independent manner or on cell-intrinsic properties that might render some cell populations or regions uniquely vulnerable. We test connectivity based explanations of spatiotemporal tau pathology progression and regional vulnerability against cell-intrinsic explanation, using regional gene expression profiles as a proxy. We find that across both exogenously seeded and non-seeded tauopathic mouse models, the connectivity network provides a better explanation than regional gene expression profiles, even when such profiles are limited to specific sets of tau risk-related genes only. Our results suggest that, regardless of the location of pathology initiation, tau pathology progression is well characterized by a model positing entirely cell-type and molecular environment independent transsynaptic spread via the mouse brain’s connectivity network. These results further suggest that regional vulnerability to tau pathology is mainly governed by connectivity with regions already exhibiting pathology, rather than by cell-intrinsic factors
Connectivity, not region-intrinsic properties, predicts regional vulnerability to progressive tau pathology in mouse models of disease
No full textSpatial patterns of genome‐wide expression profiles reflect anatomic and fiber connectivity architecture of healthy human brain
No full textFeasibility of quantitative relaxometry for prostate target localization and response assessment in magnetic resonance-guided online adaptive stereotactic body radiotherapy
No full textPurpose: Multiparametric magnetic resonance imaging (MRI) is known to provide predictors for malignancy and treatment outcome. The inclusion of these datasets in workflows for online adaptive planning remains under investigation. We demonstrate the feasibility of longitudinal relaxometry in online MR-guided adaptive stereotactic body radiotherapy (SBRT) to the prostate and dominant intra-prostatic lesion (DIL). Methods: Fifty patients with intermediate-risk prostate cancer were included in the study. The clinical target volume (CTV) was defined as the prostate gland plus 1 cm of seminal vesicles. The gross tumor volume (GTV) was defined as the DIL identified on multiparametric MRI. Online adaptive radiotherapy was delivered in a 1.5 T MR-Linac using a prescription of 800 cGy/900 cGy × 5 fractions to the CTV + 3 mm/GTV + 2 mm. Relaxometry and diffusion-weighted imaging were implemented using clinically available sequences. Test-retest measurements were performed in eight patients, at each treatment fraction. Bias and uncertainty in relaxometry measurements were also assessed using a reference phantom. Results: The bias in longitudinal/transverse relaxation times was negligible while uncertainty was within 3 %. Test-retest measurements demonstrate that bias/uncertainty in patient T1 and T2 were comparable to bias/uncertainty estimated in the phantom. Mean T1 and T2 relaxation were significantly different between the prostate and DIL. The correlation between T1, T2, and diffusion was significant in the DIL, but not in the prostate. During treatment, mean T1 in the DIL approaches mean T1 in the prostate. Conclusions: Longitudinal relaxometry for online MR-guided adaptive SBRT is feasible in a high-field MR-Linac and may provide complementary information for target delineation and response assessment
The Impact of the University Entrance Exam on EFL Education in Turkey: Pre-service English Language Teachers⿿ Perspective
No full textAbstractThe values and world views of different nations are reflected in their educational systems (Barnwell 1996). The methodologies they use to train language teachers and to assess language proficiency not only mirror and reinforce general attitudes about language and language learning but also create closed systems that are usually highly resistant to change and innovation (Locastro, 1990). Language teachers⿿ experiences as testees shape their beliefs about assessment, inform their teaching and play a central role in how they plan and implement classroom assessment practices (Bliem & Davinroy, 1997; Craig et al., 2013). Therefore, the current study, first, presents the sociocultural and historical context of how English is taught and tested in Turkey and then, it presents the beliefs and views of pre-service teachers related to assessment of English in Turkey. The views and beliefs of pre-service teachers have been gathered using questionnaires and interviews. Both qualitative and quantitative analyses of all sets of the data have been performed so that a more detailed, more representative picture is created. The results of the study not only present how language assessment policies shape and reshape teaching beliefs and practices in the country but also reveal how pre-service teachers⿿ views about assessment could be situation-specific, hence difficult to understand once placed out of context
Financing resilience efforts to confront future urban and sea-level rise flooding : Are coastal megacities in Association of Southeast Asian Nations doing enough?
No full textContinued greenhouse gas emissions will lead to a rise in temperatures, accompanied by rising sea levels threatening low-lying coastal cities. This vulnerability is especially acute in developing countries’ cities. This study reviews whether Bangkok, Manila, and Jakarta, less prepared emerging urban centers of developing countries, are investing in adaptation projects for resilience against sea-level rise and urban flooding. Sea-level rise and urban flooding resilience projects were identified in the selected cities through secondary research methods, data on multilateral climate funds, and other aggregated funding databases such as Aid Atlas, Cities Adaptation Action, and City Risk Index. Our findings show that even though these cities do have some adaptation projects to address coastal flooding and rising sea-level threats, the funding has been disparate and dispersed due to a lack of continuous, sizeable, and diverse financing options and does not come close to the requirement, given the risks, of covering potential disaster-related losses. Our findings further highlight the need to expand financing beyond multilateral funds and bilateral funding agreements and to include financial mechanisms that incentivize potential stakeholders to invest in projects that ordinarily are considered nonrevenue generating. © The Author(s) 2021.</p
Histogram and COV of regional MWF, histogram averaged over all regions.
No full text<p>(A) Histogram of regional MWF of each ROI averaged over 10 MS subjects. MWF in WM has a higher distribution than GM, and the two are statistically well separated, with p<0.001 from a student’s t-test between the WM and GM regions (B) Histogram from different subjects of MWF averaged over all regions. A t-test between the WM and GM groups yielded p<0.001. (C) COV of regional MWF for each subject, indicating low variability in regional variations in both WM and GM.</p
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