These cell adhesion related genes also provide an attractive bridge between the genetics of phenotypes that are not accompanied by gross brain pathology and those that are. Some of the cell adhesion genes that we identify in studies of cognitive ability might conceivably be directly involved in Alzheimer’s disease pathological processes [202]. However, the majority of the cognitive ability genes identified here fit with emerging views that relatively subtle differences in brain connections that contribute to individual differences in cognitive abilities also provide individual differences in “cognitive reserves” [203]. If “cognitive reserves” mitigate the cognitive impact from a given density of Alzheimer’s disease senile plaques and neurofibrillary tangles, for example, individuals with greater cognitive reserves might die without dementia despite neuropathological brain burdens that would otherwise produce significant dementia in individuals with lesser cognitive reserves [204].
