BDNF and Alzheimer disease: Additionally, a growing body of evidence demonstrates that TrkB-mediated BDNF signaling plays a critical role in the pathogenesis of multiple neurodegenerative disorders such Alzheimer’s disease (AD) and Huntington’s disease (Martin et al., 2009b, 2012; Chadwick et al., 2011b; Cong et al., 2012).