9410579 Glanzman The goal of this project is to explain the mechanisms of learning and memory in an invertebrate animal, the sea slug Aplysia. The sensory and motor neurons which mediate certain simple defensive withdrawal reflexes of Aplysia can be removed from the animal's nervous system and grown in cell culture; here they will reform their original connections (called synapses). These synapses in cell culture are ideal for analyses of the mechanisms of learning- related changes in the strength of the synapses. Recently, these researchers found that the synapses formed between Aplysia sensory and motor neurons in culture exhibit a long- term change similar to that which occurs at synapses in the vertebrate nervous system and which is thought to mediate associative learning. This synaptic change is known as "long-term potentiation" (LTP). This project will analyze the cellular mechanisms of LTP in the Aplysia synapses in cell culture and determine whether LTP of sensorimotor synapses mediates classical conditioning of Aplysia's withdrawal reflex in the whole animal. The hope is that an understanding of how the relatively simple nervous system of Aplysia mediates learning will help advance our understanding of how the far more complex nervous systems of mammals mediate more sophisticated forms of learning and memory.
