A, Example of depolarization evoked action potentials in an FS interneuron inducing PSPs in an MSN. The enlargement of the dashed box on the right shows summation of PSPs in the MSN. B, FS-to-MSN connectivity was slightly increased in pairs from R6/2 compared with WT mice. Middle and right graphs show that there was no significant difference in the success rates between pairs from WT and R6/2 mice, but there was a trend for PSP amplitudes to be larger and more variable in MSNs from R6/2 mice. C, The traces show dual recordings between a PLTS–MSN pair in an R6/2 mouse. D, There were no significant differences in the connectivity or success rate between PLTS–MSN pairs from WT and R6/2 mice.