Fig. 4.

Indices of striosome-to-matrix predominance of early-gene activation (ISMP values) are increased by acute combinations of D₁-class (SKF 81297) and D₂-class (quinpirole) dopamine receptor agonist treatments. Values indicate deviations from baseline ISMP values. These were 1.30 ± 0.21 and 1.69 ± 0.98 for the medial and lateral sectors of the caudoputamen, respectively. Dosage (in milligrams per kilogram) is indicated with corresponding symbols. Single D₁ or D₂ agonist treatments did not elevate ISMP values significantly, whereas all combined D₁-class and D₂-class agonist challenges, regardless of dose levels, produced significant increases in ISMP values. ANOVA showed a significant effect of the interaction of agonist × sector (F_(6,42) = 3.360; p< 0.009), and only the combined treatments differed significantly from baseline (Newman–Keuls). **p < 0.01.Quin, Quinpirole; SKF, SKF 81297.