MRI percentage signal change maps. Percentage signal change maps (coloured), together with their respective T2 weighted scan images (grey), from an individual mouse, at each time-point studied are provided. In each case three slices, from the 20 measured in the procedure, are shown. The slices illustrated have been taken at similar levels in each mouse and cover the range of the scan. The colour bar represents the percentage signal change, with brighter colours corresponding to higher levels of change and therefore more severe BBB dysfunction. An increase in the intensity of the colours within the signal change maps can be clearly seen from day 14 post-infection and is most apparent in animals scanned on day 28 post-infection. Brain structures relevant to the images shown are described. LV, lateral ventricle; CTX, cerebral cortex; cing, cingulum; Str, striatum; aco,‘anterior commissure; ACB, nucleus accumbens; CP, Caudate putamen; V3, third ventricle; cc, corpus callosum; HPF, hippocampal formation; HY, hypothalamus; int, internal capsule; SC, superior colliculus; AQ, aqueduct (4th ventricle); pons, pons. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)