Satoshi Takigami1, Hiroshi Sunada2, Ken Lukowiak2, Etsuro Ito3, Manabu Sakakibara4. 1. Graduate School of Bioscience, Tokai University, 317 Nishino, Numazu 410-0321, Shizuoka, Japan. 2. Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1. 3. Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki 769-2193, Japan. 4. Graduate School of Bioscience, Tokai University, 317 Nishino, Numazu 410-0321, Shizuoka, Japan. Electronic address: manabu@tokai.ac.jp.
Abstract
BACKGROUND: The pond snail Lymnaea stagnalis is capable of taste avoidance classical conditioning (TAC) with sucrose as the conditional stimulus (CS) and mechanical prodding as the unconditional stimulus (US). After successful training, feeding behavior is significantly suppressed in response to CS presentation. NEW METHOD: An automated apparatus is described for the training of multiple snails up to 10 snails at the same time. The new apparatus employs an electrical shock obtained from a 9-V dry cell to deliver a consistent and effective current amplitude of 0.4μA (i.e., the US). RESULTS: Using this apparatus, 10 snails can be conditioned simultaneously. We found that the optimal parameters to result in both short (STM) and long-term memory (LTM) were 15 paired presentations of the CS and US with a 5-min inter-trial interval (ITI) and 0.2-s current duration. However, both STM and LTM were observed with other ITIs tested. Successful TAC with only a single pairing of the CS-US occurred with a CS of 100mM sucrose solution for 60s followed by a US of 9V with 0.4μA for 5s. COMPARISON WITH EXISTING METHOD: The use of automated training apparatus for TAC will enable us to better examine the relationship between strength of CS and US.
BACKGROUND: The pond snail Lymnaea stagnalis is capable of taste avoidance classical conditioning (TAC) with sucrose as the conditional stimulus (CS) and mechanical prodding as the unconditional stimulus (US). After successful training, feeding behavior is significantly suppressed in response to CS presentation. NEW METHOD: An automated apparatus is described for the training of multiple snails up to 10 snails at the same time. The new apparatus employs an electrical shock obtained from a 9-V dry cell to deliver a consistent and effective current amplitude of 0.4μA (i.e., the US). RESULTS: Using this apparatus, 10 snails can be conditioned simultaneously. We found that the optimal parameters to result in both short (STM) and long-term memory (LTM) were 15 paired presentations of the CS and US with a 5-min inter-trial interval (ITI) and 0.2-s current duration. However, both STM and LTM were observed with other ITIs tested. Successful TAC with only a single pairing of the CS-US occurred with a CS of 100mM sucrose solution for 60s followed by a US of 9V with 0.4μA for 5s. COMPARISON WITH EXISTING METHOD: The use of automated training apparatus for TAC will enable us to better examine the relationship between strength of CS and US.