Figure 3.

Fear memory and extinction in sham and neonatal ventral hippocampus (nVH)-lesioned animals. (a) Mean (±SEM) fear behavior (% time freezing) during fear conditioning is not significantly different between sham and nVH-lesioned rats. (b) The two groups of rats also do not differ in contextual fear memory assessed by exposure to the conditioning context 24 h following fear conditioning. (c) Auditory fear memory by the presentation of conditioned stimulus (tone) 48 h following fear conditioning also did not differ in the sham and nVH-lesioned rats. (d) nVH lesion leads to impaired extinction of fear memory as lesioned animals show increased fear behavior compared with sham animals during presentation of repeated tone trials. (e) Lesioned animals show impaired recall of fear memory as assessed by tone presentation, a day after extinction learning trials. The extinction training and recall data are presented as pool of two-tone trials. *Two-way analysis of variance (ANOVA) of extinction training and recall showing significant effect of lesion (p=0.04 and p=0.008, respectively).