Training Lymnaea in the presence of a predator scent results in a long-lasting ability to form enhanced long-term memory.

Abstract

Lymnaea exposed to crayfish effluent (CE) gain an enhanced ability to form long-term memory (LTM). We test the hypothesis that a single CE exposure and operant conditioning training leads to long lasting changes in the capability of snails to form LTM when tested in pond water fourweeks later. We trained both juvenile and adult snails with a single 0.5h training session in CE and show that LTM was present 24h later. Snails trained in a similar manner in just pond water show no LTM. We then asked if such training in CE conferred enhanced memory forming capabilities on these snails fourweeks later. That is, would LTM be formed in these snails fourweeks later following a single 0.5h training session in pond water? We found that both adult and juvenile snails previously trained in CE onemonth previously had enhanced LTM formation abilities. The injection of a DNA methylation blocker, 5-AZA, prior to training in adult snails blocked enhanced LTM formation fourweeks later. Finally, this enhanced LTM forming ability was not passed on to the next generation of snails.