[Formation of a conditioned defense reflex in edible snails and changes in command neuron activity]

After 5-15 pairings of food with electrical stimulation the snail exhibited escape reaction to food, while presentation of the same stimuli at random evoked no changes in feeding behaviour. This conditioned reaction, spontaneously restored after active extinction, was retained up to 20 days. Intracellular investigation of neural events underlying the same aversive learning on half-intact preparation showed that responses of command neurones of feeding behaviour to food stimulus diminished slightly, while previously unresponsive command neurones of escape behaviour generated spike discharges in response to the same stimulus.