Animal models and behaviour: their importance for the study of memory

In our overview, we will attempt to justify the use of animal models and suggest that it is the only way to make the successive transitions between changes occurring at the molecular and cellular levels and changes at the level of behaviour in the intact organism. We will also stress the importance of criteria that have to be fulfilled in order to unravel the cellular mechanisms of memory: detectability, mimicry, anterograde alteration and retrograde alteration. We will also propose that a large number of animal models should be used to explore the great variety of potential mechanisms that may exist to explain behaviours and their modifications and in particular memory. Finally using the experimental model of Aplysia as example we will insist that to explain the total reflex in an intact animal, all the neurons - sensory neurons and different layers of excitatory and inhibitory interneurons - have to be investigated.