Question 1400
{"accessible":false,"alternatives":[{"id":6979,"text":"they have fast myelin metabolism and good blood supply"},{"id":6980,"text":"they have fast myelin metabolism and poor blood supply"},{"id":6981,"text":"they have slow myelin metabolism and good blood supply"},{"id":6982,"text":"they have slow myelin metabolism and poor blood supply"}],"archived":false,"correctAlternativeId":6981,"explanation":"\u003cp\u003e\u003ca title=\"Subcortical U-fibers\" class=\"internal\" href=\"/articles/subcortical-u-fibres-3\"\u003eSubcortical U-fibers\u003c/a\u003e represent connections between adjacent gyri of the brain in the very outer parts of the subcortical white matter. They are among the last parts of the brain to myelinate, as late as the third or fourth decade and have very slow myelin turnover. Thus diseases that affect myelin metabolism often affect these fibers relatively late.\u0026nbsp;\u003c/p\u003e\u003cp\u003eAdditionally,\u0026nbsp;their location close to the penetrating arteries that pass through and supply the cortex results in relative sparing in\u0026nbsp;chronic small vessel ischemic change which primarily involves deeper white matter, distant to both ascending perforators from the base of the brain and penetrating vessels from the cortex.\u0026nbsp;\u003c/p\u003e\u003cp\u003eIn contrast, diseases in which the damage is direct to oligodendroglial cells (e.g. PML, MS)\u0026nbsp;no such relative sparing will be evident.\u0026nbsp;\u003c/p\u003e\u003cp\u003e\u0026nbsp;\u003c/p\u003e","id":1400,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/1400","nextQuestionPath":"/articles/subcortical-u-fibres-3/questions/1396","relatedArticles":[],"alsoUsedIn":[{"id":256,"kind":"Course","title":"Multiple Sclerosis: criteria, protocol \u0026 detection","link":"https://radiopaedia.org/courses/multiple-sclerosis-criteria-protocol-detection"},{"id":507,"kind":"Course","title":"Neurodegenerative Learning Pathway - page 507","link":"https://radiopaedia.org/courses/neurodegenerative-learning-pathway/pages/507"},{"id":580,"kind":"Course","title":"Neuroradiology Lectures - page 580","link":"https://radiopaedia.org/courses/neuroradiology-lectures/pages/580"},{"id":580,"kind":"Course","title":"Radiopaedia 2020 - Lectures Only - page 580","link":"https://radiopaedia.org/courses/radiopaedia-2020-exclusive/pages/580"},{"id":580,"kind":"Course","title":"2020 Virtual Conference Private Use - page 580","link":"https://radiopaedia.org/courses/2020-virtual-conference-private-use/pages/580"},{"id":580,"kind":"Course","title":"New test course - page 580","link":"https://radiopaedia.org/courses/new-test-course/pages/580"},{"id":1067,"kind":"Course","title":"Neurodegenerative Learning Pathway - page 1067","link":"https://radiopaedia.org/courses/neurodegenerative-learning-pathway/pages/1067"},{"id":1170,"kind":"Course","title":"Adult Neuroradiology Review Course - page 1170","link":"https://radiopaedia.org/courses/adult-neuroradiology-review-course/pages/1170"},{"id":1170,"kind":"Course","title":"Adult Neuroradiology Review Course - page 1170","link":"https://radiopaedia.org/courses/adult-brain-mri-review-course-2015-online-video/pages/1170"}],"stem":"\u003cp\u003eWhy are subcortical U-fibers relatively spared in many white matter diseases?\u0026nbsp;\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/1400"}],"attemptsPercentages":[{"alternativeId":"6980","percentage":4},{"alternativeId":"6981","percentage":69},{"alternativeId":"6979","percentage":12},{"alternativeId":"6982","percentage":16}],"promptToLogin":false,"questionManager":false,"articleId":"subcortical-u-fibers"}