Spatial learning deficits after the development of dorsomedial telencephalon lesions in goldfish

The effects of lesions in the dorsal area of the caudal telencephalon (Carassius auratus) on the retention of spatial learning in goldfish were examined. The experimental paradigm was similar to the dry version of the Morris water maze for rodents. After being trained to reach a criterion, goldfish underwent surgery and were then retrained. In the retraining, dorsomedial lesions resulted in poor performance, while dorsolateral lesions did not. In a landmark task in which a small circular colored cue was set at a food location, dorsomedial lesions did not produce impairment during retraining. These results suggest that dorsomedial lesions selectively caused impairment in the retention of spatial learning.