title: One-trial conditioned taste aversion in Lymnaea: good and poor performers in long-term memory acquisition.
abstract: In the majority of studies designed to elucidate the causal mechanisms of memory formation, certain members of the experimental cohort, even though subjected to exactly the same conditioning procedures, remember significantly better than others, whereas others show little or no long-term memory (LTM) formation. To begin to address the question of why this phenomenon occurs and thereby help clarify the causal mechanism of LTM formation, we used a conditioned taste aversion (CTA) procedure on individuals of the pond snail Lymnaea stagnalis and analyzed their subsequent behavior. Using sucrose as an appetitive stimulus and KCl as an aversive stimulus, we obtained a constant ratio of ;poor' to ;good' performers for CTA-LTM. We found that approximately 40% of trained snails possessed LTM following a one-trial conditioning procedure. When we examined the time-window necessary for the memory consolidation, we found that if we cooled snails to 4 degrees C for 30 min within 10 min after the one-trial conditioning, LTM was blocked. However, with delayed cooling (i.e. longer than 10 min), LTM was present. We could further interfere with LTM formation by inducing inhibitory learning (i.e. backward conditioning) after the one-trial conditioning. Finally, we examined whether we could motivate snails to acquire LTM by depriving them of food for 5 days before the one-trial conditioning. Food-deprived snails, however, failed to exhibit LTM following the one-trial conditioning. These results will help us begin to clarify why some individuals are better at learning and forming memory for specific tasks at the neuronal level.
authors: Division of Biological Sciences, Graduate School of Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo 060-0810, Japan.
authors: Rio
authors: R
authors: Sugai
authors: Sachiyo
authors: S
authors: Azami
authors: Hatsuki
authors: H
authors: Shiga
authors: Takayuki
authors: T
authors: Watanabe
authors: Hisayo
authors: H
authors: Sadamoto
authors: Suguru
authors: S
authors: Kobayashi
authors: Dai
authors: D
authors: Hatakeyama
authors: Yutaka
authors: Y
authors: Fujito
authors: Ken
authors: K
authors: Lukowiak
authors: Etsuro
authors: E
authors: Ito
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003213:Conditioning, Psychological; D005508:Food Deprivation / Q000502:physiology; D008195:Lymnaea / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D011189:Potassium Chloride; D013395:Sucrose; D013649:Taste / Q000502:physiology*; D013696:Temperature
chemical_list: D013395:Sucrose; D011189:Potassium Chloride