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Neurophysiological correlates of unconditioned and conditioned feeding behaviour in the pond snail Lymnaea stagnalis

journal contribution
posted on 2023-06-07, 22:16 authored by Kevin StarasKevin Staras, George KemenesGeorge Kemenes, Paul R Benjamin
We used a behavioral appetitive learning paradigm followed by electrophysiological analysis to investigate the neuronal expression of appetitive conditioning in Lymnaea. We first established the levels of unconditioned and conditioned feeding responses in intact animals. We then demonstrated that neuronal correlates of both unconditioned responses to touch and food and a conditioned response to touch could be found in semiintact preparations of the same animals that had been subjected to behavioral tests and conditioning trials. In the conditioning experiments, the experimental animals received 15 trials in which touch to the lips, the conditioned stimulus (CS), was paired with sucrose, the unconditioned food stimulus (US). Control animals received 15 presentations of either CS or US, or both, applied in a random manner. After training, a strong conditioned response to touch was established in the experimental but not in the control groups. For subsequent electrophysiological analysis of posttraining neuronal responses to the touch CS, semi-intact preparations were set up from the same animals that had been behaviorally conditioned or subjected to control procedures. Intracellular recordings, made from previously identified motoneurons of the feeding system, allowed the fictive feeding response to the CS to be monitored. In experimental preparations, touch applied to the lips evoked significantly more fictive feeding cycles than in controls, and this demonstrated the existence of a neurophysiological correlate of the appetitively conditioned response observed in the whole animals.


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  • Published


Journal of Neurophysiology




Journal of Neurophysiology





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  • Neuroscience Publications


First study to make direct quantitive comparisons between unconditioned and conditioned feeding responses in intact animals and the cellular expression of these responses in semi-intact preparations made from the same animals

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