APOE and early-onset autosomal dominant Alzheimer disease: It is interesting to note that previous clinical studies have consistently demonstrated an increased neuronal activity in the hippocampus and cortex in non-demented individuals at high risk for AD including APOE4 carriers, minor cognitive impairment (MCI) or at presymptomatic stage of familial Alzheimer’s disease [10, 72], and individuals with early Alzheimer’s disease are prone to developing seizures [87].