A thermal stressor, propranolol and LTM formation in freshly collected Lymnaea

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.

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 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>


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

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

2019 ◽  
Author(s):  
cika suteja

In daily life, humans can not be separated from the name of learning and remembering. Learning and remembering is the basis for someone to adapt their behavior to the environment. The brain is the organ that regulates learning and memory. The brain will store and bring back the information needed. Decline in memory usually occurs during old age but does not rule out the possibility of happening at a young age too. Decreasing memory recall at a young age is usually caused by a lack of physical activity. Sports is one of the factors that can improve memory. Exercise can improve blood circulation so that the brain can be well-nourished and will work optimally. To make our memories into long-term memories can be done by repeating the information obtained. Because repetition can accelerate and increase consolidation. Information entered in long-term memory will be grouped according to the type of information. This grouping serves to facilitate the search for the desired information. Short-term information will forever be forgotten, but long-term information can last up to a lifetime.


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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