Structural brain differences between SH (spontaneously hypertensive) and WKY (Wistar Kyoto) rats. On T2-weighted magnetic resonance imaging (MRI) ventricles were significantly enlarged in SHR (A), whereas corpus callosum (CC) (B) and total brain volumes (C) were significantly reduced. Representative T2-weighted coronal slices display large hyperintense lateral ventricles in SHR, which are barely visible in WKY. The magnification highlights narrowing of the hypointense CC in SHR. Post-mortal quantification of myelin by Luxol Fast Blue stain revealed a significantly decreased optical density (i.e. an increased myelin index) in the CC of SHR (D). Data are mean ± SD. **p < 0.01 and ***p < 0.001 by t-test for n = 10 (A-C) or n = 4 animals/group (D). Scale bar: 250 μm.