One-trial associative learning by an isolated molluscan CNS: Use of different chemoreceptors for training and testing

An isolated preparation of the lips, cerebral ganglia and buccal ganglia of the terrestrial slug, Limax maximus, can display one-trial associative learning. The lip-brain preparation can learn to suppress feeding motor program responses to lip stimulation with a standard food extract after a single pairing of food extract and quinidine stimulation to the isolated lips. Learning can occur with training stimuli applied to one lip and testing stimuli applied to the opposite, 'naive' lip. Learning can also occur if the food extract and quinidine are applied during training to opposite lips. These results indicate that the synaptic alteration due to learning occurs in the CNS, not at the sensory periphery.