Fos in the prelimbic cortex in Del mice shows increased sensitivity to the 5-HT2A antagonist M100907 and decreased sensitivity to the agonist DOI. A, A’ Fos in saline treated WT and Del mice is comparable. B, B’ M100907 produces a significant reduction in Fos in both genotypes, to a greater degree in Del mice Tukey HSD p = 0.008 for WT; p = 8.2×10−7 Del. C, C’ DOI increases Fos in WT mice but not Del mice p = 1.8×10−6. N = 6–9 per group * = p < 0.05. D Boxed area shows region sampled. E. Quantification * = p < 0.05, Group size, n = 5–9 mice in each group, with at least 2 of each sex.