Intracranial self-stimulation also facilitates learning in a visual discrimination task in the Morris water maze in rats

• Self-stimulation (ICSS) facilitates the learning of a visual discrimination task.
• A direct, instead of a trial and error strategy is preferred by ICSS animals.
• Number of errors is a more sensitive measure than latency in visual discrimination.
• A strengthened implicit memory caused by ICSS, challenges reversal learning.

Intracranial self-Stimulation (ICSS) of the medial forebrain bundle is a treatment capable of consistently facilitating acquisition of learning and memory in a wide array of experimental paradigms in rats. However, the evidence supporting this effect on implicit memory comes mainly from classical conditioning and avoidance tasks. The present work aims to determine whether ICSS would also improve the performance of rats in another type of implicit task such as cued simultaneous visual discrimination in the Morris Water Maze. The ICSS treatment was administered immediately after each of the five acquisition sessions and its effects on retention and reversal were evaluated 72 h later. Results showed that ICSS subjects committed fewer errors than Sham subjects and adopted more accurate trajectories during the acquisition of the task. This improvement was maintained until the probe test at 72 h. However, ICSS animals experienced more difficulties than the Sham group during the reversal of the same learning, reflecting an impairment in cognitive flexibility. We conclude that post-training ICSS could also be an effective treatment for improving implicit visual discrimination learning and memory.