Figure 5.

CA3 and MEC are involved in supporting spatial navigation and cue approach performance. Retention testing comprised all rats for 2 days (n = 4 TC, 5 CA3, and 6 MEC rats), and extended to 5 days for a subgroup (n = 4 TC, 5 CA3, and 2 MEC rats). In the spatial task (left), the performance of CA3 and MEC lesioned animals was impaired by comparison to their own pre-lesion levels, and to post-lesion level of TC group. Training reduced the behavioral deficit of the MEC lesion group but not of the CA3 lesion group. The more severe and permanent effect of CA3 lesions is well highlighted by the higher number of trials these rats needed to be switched to the next trial block throughout testing (inset). Notably, the lesions also affected the cue response (right). However, in this case the performance of the lesioned rats did not deteriorate when compared to pre-lesion levels. Dashed lines at the 50% mark indicate random level performance. Solid lines at the 20% mark indicate the criterion level each animal had to reach before surgery. Data points represent mean ± s.e.m.