Cell membrane capacitance (A) and input resistance (B) for medium-sized spiny neurons (MSNs) recorded in acute slices prepared from R6/2s and pooled wild-types (WTs) at 21, 40, and 80 days of age. *P < 0.05, ***P < 0.001 with respect to WTs; †P < 0.05, ††P < 0.01, †††P < 0.001 with respect to cytosine-adenine-guanine (CAG)160; ‡P < 0.05 with respect to CAG310. In Figs. 1–5, numbers within bars indicate the number of cells.