Connecting model species to nature: predator-induced long-term sensitization in Aplysia californica.

Previous research on sensitization in Aplysia was based entirely on unnatural noxious stimuli, usually electric shock, until our laboratory found that a natural noxious stimulus, a single sublethal lobster attack, causes short-term sensitization. We here extend that finding by demonstrating that multiple lobster attacks induce long-term sensitization (≥24 h) as well as similar, although not identical, neuronal correlates as observed after electric shock. Together these findings establish long- and short-term sensitization caused by sublethal predator attack as a natural equivalent to sensitization caused by artificial stimuli.

Lobster attack induces sensitization in the sea hare, Aplysia californica.

Studies of the neural mechanisms of learning, especially of sensitization, have benefitted from extensive research on the model species, Aplysia californica (hereafter Aplysia). Considering this volume of literature on mechanisms, it is surprising that our understanding of the ecological context of sensitization in Aplysia is completely lacking. Indeed, the widespread use of strong electric shock to induce sensitization (an enhancement of withdrawal reflexes following noxious stimulation) is completely unnatural and leaves unanswered the question of whether this simple form of learning has any ecological relevance.