Long-term memory of an operantly conditioned respiratory behaviour pattern in lymnaea stagnalis

1998 ◽  
Vol 201 (6) ◽  
pp. 877-882 ◽  
Author(s):  
K Lukowiak ◽  
R Cotter ◽  
J Westly ◽  
E Ringseis ◽  
G Spencer ◽  
...  

The freshwater snail Lymnaea stagnalis breaths bimodally either through its skin (cutaneous respiration) or via a rudimentary lung opening called the pneumostome (aerial respiration). Aerial respiratory behaviour can be operantly conditioned. Animals placed in an aquatic, hypoxic environment received a tactile stimulus to the pneumostome area every time they attempted to breathe. Over a period of five training sessions (2.5 days), the animals learned not to breathe, and the number of stimuli received in the fifth session was significantly lower than in the first session. These changes in the respiratory behaviour following the operant paradigm were shown to persist for at least 24 h. We aimed to determine whether the changes in the learned behaviour would persist for longer. We obtained direct evidence that the behavioural changes following operant conditioning persisted for at least 4 weeks following the last training session. However, we found that the persistence of this memory was dependent upon the training procedure used. Memory persisted longer following a spaced training procedure (4 weeks) as opposed to a massed training procedure (2 weeks). Yoked control animals showed no changes in their respiratory behaviour over the same time periods. However, if these yoked control animals were subjected to an operant conditioning procedure, their ability to learn was not impeded. This study demonstrated that operant conditioning of a behaviour pattern in a molluscan preparation can result in long-term memory and that the persistence of the memory is contingent on the training procedure used. <P>

2002 ◽  
Vol 205 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Kim Smyth ◽  
Susan Sangha ◽  
Ken Lukowiak

SUMMARY Aerial respiratory behaviour can be operantly conditioned in Lymnaea stagnalis and, depending on the interval between the training sessions, memories of significantly different durations are produced. In naïve snails, a 15 min training procedure with a 30 min interval between three training sessions results in memory that persists for only 3 h (intermediate-term memory, ITM); whilst if the three 15 min training sessions are separated by a 1 h interval memory persists for 48 h (long-term memory, LTM). We found that if ITM training preceded LTM training, then LTM would persist for 24 h longer. This augmenting effect on LTM persistence could be demonstrated for up to 5 h following the last ITM training session, even though ITM was not observed at that time. However, if LTM training ensued 8 h after the last ITM training session, an augmented LTM did not occur. Extinguishing the memory produced by the ITM training procedure also prevented augmentation of LTM. That is, if an extinction procedure was given to the snails after the ITM training procedure, LTM did not persist longer than 48 h. Thus, at the behavioural level, ITM and LTM are interconnected.


2002 ◽  
Vol 205 (8) ◽  
pp. 1171-1178 ◽  
Author(s):  
Susan Sangha ◽  
Chloe McComb ◽  
Andi Scheibenstock ◽  
Christine Johannes ◽  
Ken Lukowiak

SUMMARY A continuous schedule of reinforcement (CR) in an operant conditioning procedure results in the acquisition of associative learning and the formation of long-term memory. A 50 % partial reinforcement (PR) schedule does not result in learning. The sequence of PR—CR training has different and significant effects on memory retention and resistance to extinction. A CR/PR schedule results in a longer-lasting memory than a PR/CR schedule. Moreover,the memory produced by the CR/PR schedule is resistant to extinction training. In contrast, extinction occurs following the PR/CR schedule.


1998 ◽  
Vol 5 (3) ◽  
pp. 204-219 ◽  
Author(s):  
Dina Botzer ◽  
Silvia Markovich ◽  
Abraham J. Susswein

In many organisms, memory after training can be separated into a number of processes. We now report that separable memory processes are also initiated by a training procedure affectingAplysia feeding behavior, a model system for examining the neural mechanisms underlying the regulation of a complex behavior. Four distinct memory process were identified: (1) a very short-term memory that declines within 15 min, (2) a short-term memory that persists for 0.5–1.0 hr, (3) an intermediate-term memory, observed 4 hr after training, and (4) a long-term memory that is seen only after a 12- to 24-hr delay. The four memory processes can be distinguished by the different training procedures that are required to elicit them. A single 5-min training session is sufficient to elicit the very short-term memory. However, a longer training session that continues until the animal stops responding to food is needed to elicit short-term memory. Intermediate-term memory is observed only after a spaced training procedure (three 5-min training sessions separated by 30-min intervals). A single 5-min training session that does not cause either short-term or intermediate-term memory is sufficient to induce long-term memory, indicating that short- and long-term memory are independent, parallel processes. Short- and long-term memory can also be separated by the effects of a post-training experience. Long-term, but not short-term, memory can be attenuated by cooling animals immediately after training. Cooling before the training does not affect either the training or the subsequent short- or long-term memory.


Author(s):  
Cayley Swinton ◽  
Erin Swinton ◽  
Iain Phillips ◽  
Ken Lukowiak

A heat stressor (1h at 30o C) in Lymnaea stagnalis before operant conditioning training of aerial respiration is sufficient to enhance long-term memory (LTM) formation in average cognitive-ability, laboratory-reared, inbred snails. However, in freshly collected outbred snails the same heat stressor blocks LTM formation in smart cognitive phenotype but not in average cognitive phenotype strains. Here we hypothesize that: 1) preventing the stress associated with the heat stressor before training allows LTM to form in the smart phenotype strains ; and 2) alleviating the stress before a memory recall session allows a formed LTM to be recalled in the smart phenotype strains. We found that an injection of propranolol, which mitigates the stressor, before snails experience the heat stressor enabled two strains of the smart phenotype snails to form LTM formation, consistent with our first hypothesis. However, the injection of propranolol before a memory test session, did not alleviate a memory recall block in the smart phenotype snails. Thus, our second hypothesis was not supported. Thus, smart cognitive phenotype snails encountering a heat stressor have an inability to form LTM, but this inability can be overcome by the pre-injection of propranolol.


2012 ◽  
Vol 215 (24) ◽  
pp. 4322-4329 ◽  
Author(s):  
M. L. Teskey ◽  
K. S. Lukowiak ◽  
H. Riaz ◽  
S. Dalesman ◽  
K. Lukowiak

1977 ◽  
Vol 196 (1123) ◽  
pp. 171-195 ◽  

Cycloheximide injected into the brains of chickens 10 min before training does not effect their learning of a visual discrimination task, or memory of that task for at least 1 h after training. When tested 24 h later no memory of the training procedure is detectable. In contrast, ouabain injected 10 min before training prevents the expression of learning during training. The block lasts for up to 1 h, but from that time on memory begins to appear. Ouabain does not affect performance when injected just before testing for memory retention 24 h after training. It therefore affects neither the readout of long-term memory nor motivation nor perceptual abilities necessary for performance of the learning task. In birds treated with ouabain, after training on an operant task for heat reward by a procedure requiring a fixed number of reinforcements, memory is absent 20 min later but is well established at 24 h. Cycloheximide blocks long-term memory of this task. Like ouabain, ethacrynic acid, injected into the brain of chickens 10 min before training prevents the expression of learning of visual discrimination. Ethacrynic acid hastens the decline of memory after one-trial passive avoidance learning. It also blocks observational learning. We conclude that ouabain and ethacrynic acid block access to short-term memory, whereas cycloheximide interferes with the registration of long-term memory. Comparing the pharmacology of ethacrynic acid and ouabain their common known actions are on the Na/K fluxes across cell membranes. We suggest that long lasting changes in distribution of these ions in recently active nerve cells may be at the basis of access to memory during and shortly after learning.


2011 ◽  
Vol 82 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Sarah Dalesman ◽  
Simon D. Rundle ◽  
Ken Lukowiak

2002 ◽  
Vol 88 (4) ◽  
pp. 1584-1591 ◽  
Author(s):  
Andi Scheibenstock ◽  
Darin Krygier ◽  
Zara Haque ◽  
Naweed Syed ◽  
Ken Lukowiak

The cellular basis of long-term memory (LTM) storage is not completely known. We have developed a preparation where we are able to specify that a single identified neuron, Right Pedal Dorsal 1 (RPeD1), is a site of LTM formation of associative learning in the pond snail, Lymnaea stagnalis. We demonstrated this by ablating the soma of the neuron but leaving behind its functional primary neurite, as evidenced by electrophysiological and behavioral analyses. The soma-less RPeD1 neurite continues to be a necessary participant in the mediation of aerial respiratory behavior, associative learning, and intermediate-term memory (ITM); however, LTM cannot be formed. However, if RPeD1's soma is ablated after LTM consolidation has occurred, LTM can still be accessed. Thus the soma of RPeD1 is a site of LTM formation.


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