The causal mechanisms of histopathological abnormalities associated with aberrant connectivity remain elusive, yet altered expression of brain-derived neurotrophic factor (BDNF) and perturbed BDNF signaling are commonly reported for several neurological diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS) [14, 15]. This evidence concerns the gene BDNF and Alzheimer disease.