BCL11BKO MSNs exhibit no dopaminergic modulation of excitatory signaling and present with impaired glutamate-evoked Ca2+ signals. (A) All basic membrane properties, including RMP, input resistance, membrane time constant, and capacitance, were measured and found to not differ significantly between the genotypes. (B) Representative traces of action potentials evoked by steps of current injection in Ctrl (black) and BCL11BKO (red) MSNs (left). Increased firing frequency in response to current injection is observed in BCL11BKO MSNs (right) (Mann-Whitney U test: U = 90.5, ∗p = .014). (C) Representative traces and quantification of current responses to DL-glutamic acid (200 μM, 30 ms) in the absence or presence of SKF-81297 (SKF) (10 μM) in Ctrl and BCL11BKO MSNs. Only Ctrl MSNs show a significant enhancement of glutamatergic transmission induced by activation of dopaminergic signaling (two-way analysis of variance with post hoc Bonferroni test: genotype: F1,40 = 8.860, p = .005; treatment: F1,40 = 4.093, p = .049; Ctrl vs. KO: p = .123, Ctrl vs. Ctrl + SKF: ∗p = .038, KO vs. KO + SKF: p = .463, Ctrl + SKF vs. KO + SKF: ∗p = .014). (D–F) Glutamate-evoked intracellular Ca2+ signals recorded in response to repetitive stimulation (20 μM, 1 minute, 19 pulses, black bars) in control and BCL11BKO MSNs, CTX neurons, and mDA neurons (left column). (D) Glutamate-stimulated BCL11BKO MSNs accumulate higher intracellular Ca2+ levels over time and respond to fewer glutamate pulses compared with Ctrl cells (Mann-Whitney U test: MSN ΔFend/F0: U = 621,047, ∗∗∗p = 1.8 × 10−25; responses: U = 117,472, ∗∗∗p = 2.8 × 10−153). (E, F) Only a small deficit is present in the number of glutamate-evoked responses in BCL11BKO CTX neurons, while no differences can be seen in mDA neurons (Mann-Whitney U test: CTX responses: U = 287,590, ∗p = .043). All line graphs and dot plots depict mean ± SEM for each genotype. Box-and-whisker plots depict data for each genotype (center line, median; +, mean; box limits, upper and lower quartiles; whiskers, 2.5 and 97.5 percentiles). Means for individual clones are indicated by red-shaded circles next to BCL11BKO data. See also Figure S4. AP, action potential; Ctrl, control; CTX, cortical glutamatergic; KO, knockout; mDA, midbrain dopamine; MSNs, medium spiny neurons; n.s., not significant; RMP, resting membrane potential.