Effects of walnut oil on long-term memory of rats in a multiple-T-maze

Nutrition represents an important aspect regarding neuronal and cognitive functions. Especially the essential omega-3 polyunsaturated fatty acids (PUFAs) can positively affect cognitive abilities as indicated by various findings in humans and rodent models. Some important PUFA sources have been well investigated in this context while others received less attention, which also applies to walnut oil. Moreover, the majority of studies in rodents used similar types of mazes to assess learning and memory abilities and rarely investigated long-term memory abilities. For this pilot study, rats were supplemented with walnut oil for eight weeks (PUFA group) or received a control diet (control group) before they were trained to a three-choice multiple-T-maze task to test long-term memory abilities four weeks afterwards. In the end of the training phase as well as in the long-term memory test, no differences between diet groups were detected in the time to finish the task or the number of conducted errors. However, comparing the training phase and the memory test revealed an increase in the time and errors in the control group while the PUFA group remained constant in its performance. The findings presented here indicate that supplementation of walnut oil high in PUFAs can positively affect long-term memory formation in rats in a multiple-T-maze. Future studies may similarly consider alternative and more challenging maze tasks to assess the magnitude of cognitive influences.