Figure 4.

Differential Fos expression. A, Images of Fos-labeled cells in PRH of a control rat. Paired-viewing procedure: I, hemisphere chiefly processing familiar pictures; II, hemisphere chiefly processing novel pictures. Note the higher number of Fos-positive cells on the novel side (II). Scale bar, 100 μm. B, Systemic normalized Fos counts for novel and familiar hemispheres for saline- or verapamil-treated rats for the following regions: PRH, Te2, AU, and ENT. In PRH and Te2, a significant interaction between novelty/familiarity and drug treatment was found, indicating that the differential in Fos expression between novel and familiar hemispheres of saline-treated rats was significantly different from that for verapamil-treated animals. Repeated-measures ANOVA effect of novelty/familiarity: *p < 0.05, ***p < 0.001. Error bars indicate SEM.