Figure 3.

FSIs show consistent drug-induced firing rate changes, whereas MSNs do not. (a and b) Scatter plots comparing spike firing rates (log scale) for MSNs (a) and FSIs (b), after injection of drug vs saline control. ‘Low etic'=0.2 mg/kg eticlopride, ‘high etic'=1 mg/kg eticlopride, ‘low amph'=0.5 mg/kg amphetamine, ‘high amph'=2.5 mg/kg amphetamine. Circle color key is the same as Figure 2. (c and d) Proportions of MSNs, FSIs with each type of drug response. As in (a and b), black indicates increases, gray decreases, and white no change. Numbers on bars indicate absolute numbers of cells in each category. (e and f) Mean firing rates for the MSN, FSI populations during saline and drug time blocks. Asterisks indicate significant differences between saline and drug log firing rates (^*p<0.05, ^**p<0.01 paired t-test).