Mechanisms of learning and memory in pond snails discovered by following biological hierarchy

Abstract

  Various kinds of approaches using behavioral, physiological, cellular biological and molecular biological techniques have been developed for understanding the mechanisms of learning and memory. However, the results of these analyses are intricately related to one another, and the complexity makes it difficult to clarify the association between each result and to provide an overview of the mechanism for learning and memory. To overcome this difficulty, it is important to develop an experimental system where correct tracing of the biological hierarchy from behaviors to genes via brains and neurons is possible. Careful selection of an experimental animal that can learn complex conditions with a simple brain is essential for this purpose. A pond snail, Lymnaea stagnalis, is particularly suitable for such studies. In this article, I review recent progress in the study of mechanisms for the conditioned taste aversion in Lymnaea, and introduce an application of “epigenetics”, which is recently attracting considerable attention in the field of neurobiology.