fig3

Figure 3. Subpial cortical grey matter lesions are the most frequent and occupy the greatest area. Anti-PLP immunostaining of section A3 of MS253, MS224 and MS257 revealed subpial (Type III/IV cortical lesions, red mask), intracortical (Type II cortical lesion, orange mask) and leukocortical (Type I cortical lesion, yellow mask) lesions. Lesions of the deep grey matter (green) and lesions of white matter (blue mask) are also shown (A). Subpial (Type III/IV) lesions were predominant and often spanned multiple gyri (B). Of 1884 separate lesions, 72.3% were subpial cortical grey matter lesions (C). By plotting the average area of each lesion type (calculated per section) and represented per case, we show the heterogeneity of lesion size across our cohort (D), and how subpial cortical lesions contribute a large component of the lesion burden, especially in those cases most affected (from MS366 to MS257, for example). Ave: average; Cx: cortical; GML: grey matter lesion; PLP: proteolipid protein immunohistochemistry; WML: white matter lesion. (A) Scale bar = 1 cm; (B) Scale bar = 1 mm