PPP1R1B and Huntington disease: Later, when HD mice experienced reduced performance at the water-reaching task, we and others also reported increased time to traverse the tapered beam, decreased latency to fall from the rotarod, and decreased DARPP-32 expression in striatal MSNs (Smith, 2014; Peng et al., 2016; Southwell et al., 2016; Liu et al., 2021).