The pond snail Lymnaea learns and remembers not to respond to a food substance that is called conditioned taste aversion (CTA). The possible relationship between how well snails learn following taste-aversion training and brain dopamine contents is not known. We examined this relationship and found the followings. First, snails in the act of eating just before the commencement of training had the poor learning and had the highest dopamine contents in the brain. Second, snails, which had an ad libitum access to food but were not eating just before training, achieved the average grades and had the lower dopamine contents. Third, snails food-deprived for one day before training earned the best grades and had the significantly lower contents of dopamine. There was a negative correlation between the CTA grades and the brain dopamine contents in these 3 cohorts. Fourth, snails food-deprived for 5 days before training showed the poor grades and had the higher dopamine contents. That is, severe hunger increased the dopamine content in the brain. Because dopamine functions as a reward transmitter, CTA in the severely deprived snails (i.e., the forth cohort) was thought to be mitigated by a high dopamine content.
- Received September 4, 2016.
- Accepted October 31, 2016.
- © 2016. Published by The Company of Biologists Ltd
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