Neuroprotection and neuroregeneration:roles for the white matter

Efficient strategies for neuroprotection and repair are still an unmet medical need for neurodegenerative diseases and lesions of the central nervous system.Over the last few decades,a great deal of attention has been focused on white matter as a potential therapeutic target,mainly due to the discovery of the oligodendrocyte precursor cells in the adult central nervous system,a cell type able to fully repair myelin damage,and to the development of advanced imaging techniques to visualize and measure white matter lesions.The combination of these two events has greatly increased the body of research into white matter alte rations in central nervous system lesions and neurodegenerative diseases and has identified the oligodendrocyte precursor cell as a putative target for white matter lesion repair,thus indirectly contributing to neuroprotection.This review aims to discuss the potential of white matter as a therapeutic target for neuroprotection in lesions and diseases of the central nervous system.Pivot conditions are discussed,specifically multiple scle rosis as a white matter disease;spinal cord injury,the acute lesion of a central nervous system component where white matter prevails over the gray matte r,and Alzheimer's disease,where the white matter was considered an ancilla ry component until recently.We first describe oligodendrocyte precursor cell biology and developmental myelination,and its regulation by thyroid hormones,then briefly describe white matter imaging techniques,which are providing information on white matter involvement in central nervous system lesions and degenerative diseases.Finally,we discuss pathological mechanisms which interfere with myelin repair in adulthood.

Multifractal analysis of white matter structural changes on 3D magnetic resonance imaging between normal aging and early Alzheimer's disease

Applications of multifractal analysis to white matter structure changes on magnetic resonance imaging（MRI） have recently received increasing attentions. Although some progresses have been made, there is no evident study on applying multifractal analysis to evaluate the white matter structural changes on MRI for Alzheimer＇s disease（AD） research. In this paper, to explore multifractal analysis of white matter structural changes on 3D MRI volumes between normal aging and early AD, we not only extend the traditional box-counting multifractal analysis（BCMA） into the 3D case, but also propose a modified integer ratio based BCMA（IRBCMA） algorithm to compensate for the rigid division rule in BCMA. We verify multifractal characteristics in 3D white matter MRI volumes. In addition to the previously well studied multifractal feature,△α, we also demonstrated △ f as an alternative and effective multifractal feature to distinguish NC from AD subjects.Both △α and △ f are found to have strong positive correlation with the clinical MMSE scores with statistical significance.Moreover, the proposed IRBCMA can be an alternative and more accurate algorithm for 3D volume analysis. Our findings highlight the potential usefulness of multifractal analysis, which may contribute to clarify some aspects of the etiology of AD through detection of structural changes in white matter.

Texture and color enhancement imaging for detecting colorectal adenomas: Good, but not good enough

Texture and color enhancement imaging(TXI)has been developed as a novel image-enhancing endoscopy.However,the effectiveness of TXI detecting adenomas is inferior to narrow band imaging.Thus,future studies will need to focus on investigating the feasibility of such combination in clinical settings in order to provide patients with more accurate diagnoses.

A Fiber Tractography Study of Social-Emotional Related Fiber Tracts in Children and Adolescents with Autism Spectrum Disorder

The symptoms of autism spectrum disorder（ASD） have been hypothesized to be caused by changes in brain connectivity. From the clinical perspective, the‘‘disconnectivity＇＇ hypothesis has been used to explain characteristic impairments in ‘‘socio-emotional＇＇ function.Therefore, in this study we compared the facial emotional recognition（FER） feature and the integrity of socialemotional-related white-matter tracts between children and adolescents with high-functioning ASD（HFA） and their typically developing（TD） counterparts. The correlation between the two factors was explored to find out if impairment of the white-matter tracts is the neural basis of social-emotional disorders. Compared with the TD group,FER was significantly impaired and the fractional anisotropy value of the right cingulate fasciculus was increased in the HFA group（P ／ 0.01）. In conclusion, the FER function of children and adolescents with HFA was impaired and the microstructure of the cingulate fasciculus had abnormalities.