مادة بيضاء
White matter integrity has also been shown to relate to cognitive change. Specifically, white matter integrity in the splenium of the corpus callosum has been found to be a marker of healthy cognitive ageing. Lower white matter hyperintensity load has also been considered a sign of successful cognitive ageing, because it was associated with higher general cognitive ability and faster processing speed at age 73 after age 11 intelligence was controlled for.