Complex associative learning in small neural networks

The biophysical and biochemical mechanisms underlying complex associative learning and memory storage provide a suitable challenge for modern neuroscience. A new sense of optimism prevails, based on accelerating progress with studies of learning at several levels of analysis: behavioral, neural system, biophysical and biochemical. Gastropod molluscs provide particularly accessible neural systems for coordinated cellular and behavioral study of associative learning^1-4. Our work with the terrestrial slug Limax maximus attempts to capitalize on its highly developed learning ability for discriminating food odors and tastes, and the accessibility and robustness of the neurons in its feeding control network. The goals, strategy and analytical tools employed in this work on molluscs are very similar to analyses of mammalian nictatating membrane conditioning⁵ and avian heart rate conditioning⁶. Ultimately we wish to know whether any elements of these complex learning mechanisms are shared by molluscs and mammals.