Long-term habituation in the marine mollusc Tritonia diomedea

Tritonia diomedea is one of several gastropod molluscs used to study cellular mechanisms of learning and memory. Previous studies in this organism have focused on short-term habituation and sensitization. This report presents the first detailed description of long-term habituation in Tritonia. Experimental animals were given 11 swim sessions, each consisting of 10 trials, over 6 days, during which they typically displayed an initial sensitization, followed by short-term, within-session habituation. Responses were compared to controls, which were given a single stimulus per day. Cycle number habituation steadily accumulated over the days of training, and then persisted for at least 2 days after the end of training. These findings will permit comparative studies of the cellular mechanisms of short- and long-term memory in this highly tractable model system.