BDNF and Huntington disease: Reduced BDNF in HD is viewed as contributing to dysfunction and degeneration of MSNs and thus the cortical-striatal pathway (Blumenstock and Dudanova, 2020; Cummings et al., 2007; Dallerac et al., 2011; Kovalenko et al., 2018; Milnerwood et al., 2006; Milnerwood and Raymond, 2007; Murphy et al., 2000; Nithianantharajah and Hannan, 2013; Puigdellivol et al., 2015).