Figure 4.

(A) Comparison of the AC group with the IC group: At the coronal plane equivalent to −2.3 mm from bregma (Zilles 1985), no significant differences were found between the AC and IC group, but there was a group by position interaction (p < .01). Thickness also varied by position (p < .001.). (B) At the coronal plane equivalent to −1.8 mm from bregma (Zilles 1985), thickness varied by position (p < .001). There were no differences between the AC and IC groups and no interactions. (C) At the coronal plane equivalent to that of −0.8 mm from bregma (Zilles 1985), the thickness of the medial region of interest (ROI) was greater in the AC than IC group (p < .01). Thickness also varied over position (p < .01), but there was no group by position interaction. The AC group, relative to the IC group, had a trend for a thicker lateral ROI (p = .026). Within this lateral region of interest, thickness also varied by position (p < .001). (D) At the coronal plane equivalent to that of −0.3 mm from bregma (Zilles 1985), the rats in the AC group had significantly thicker cortices in the medial ROI than rats in the IC group (p < .01). Similarly, there was a trend for a group difference in thickness in the lateral ROI (p < .05). In both the medial and lateral ROIs, there was a trend for thickness to vary over position (p < .05).