Gastropod Learning and Memory (Aplysia, Hermissenda, Lymnaea, and Others)

Euopisthobranchia (Aplysia), Nudipleura (Tritonia, Hermissenda, Pleurobranchaea), and Panpulmonata (Lymnaea, Helix, Limax) gastropod mollusks exhibit a variety of reflex, rhythmic, and motivated behaviors that can be modified by elementary forms of learning and memory. The relative simplicity of their nervous systems and behavioral repertoires has allowed the uncovering of processes of neuronal and synaptic plasticity underlying non-associative learning, such as habituation, sensitization, and different forms of associative learning, such as classical and operant conditioning. Decades of work on these simpler and accessible animal systems have almost uniquely yielded an understanding into the mechanistic basis of learning and memory spanning behavior, neuronal circuitry, and molecules. Given the conservative nature of evolutionary processes, the mechanisms deciphered have also provided valuable insights into the neural basis of learning and memory in other metazoans, including higher vertebrates.