Figure 5.

A, Example of a D1–D2 connected pair from a WT mouse. Left, IR-DIC image. Right, Fluorescent image. Only the circled cell on the bottom displays fluorescence. B, Example of a connection between two D1-MSNs from an R6/2 mouse. Traces on the right are the enlarged area in the box. C, In MSN connected pairs (10/24) from WT mice, only unidirectional connectivity occurred. Forty percent (4/10) were D1–D1 and 20% (2/10) were D2–D2 connections. Mixed D1–D2 pairs were connected 40% (4/10) of the time. In MSN connected pairs (7/24) from R6/2 mice, two displayed bidirectional connectivity (counted as two connections, D1 to D1, D1 to D2). The great proportion of connected pairs was between D1–D1 MSNs (6/7). No connected D2–D2 pairs were observed. There also were fewer connected mixed pairs in R6/2 mice when compared with WTs. D, Success rates for D1–D1 connections were slightly higher for R6/2 than WT MSNs. The success rates for R6/2 pairs for D1–D2 and D2–D1 connections were based on one pair in each group and there was no SE.