How Stress Alters Memory in ‘Smart’ SnailsReportar como inadecuado

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Cognitive ability varies within species, but whether this variation alters the manner in which memory formation is affected by environmental stress is unclear. The great pond snail, Lymnaea stagnalis, is commonly used as model species in studies of learning and memory. The majority of those studies used a single laboratory strain i.e. the Dutch strain originating from a wild population in the Netherlands. However, our recent work has identified natural populations that demonstrate significantly enhanced long-term memory LTM formation relative to the Dutch strain following operant conditioning of aerial respiratory behaviour. Here we assess how two populations with enhanced memory formation i.e. ‘smart’ snails, one from Canada Trans Canada 1: TC1 and one from the U.K. Chilton Moor: CM respond to ecologically relevant stressors. In control conditions the Dutch strain forms memory lasting 1–3 h following a single 0.5 h training session in our standard calcium pond water 80 mg-l Ca2+, whereas the TC1 and CM populations formed LTM lasting 5+ days following this training regime. Exposure to low environmental calcium pond water 20 mg-l Ca2+, which blocks LTM in the Dutch strain, reduced LTM retention to 24 h in the TC1 and CM populations. Crowding 20 snails in 100 ml immediately prior to training blocks LTM in the Dutch strain, and also did so in TC1 and CM populations. Therefore, snails with enhanced cognitive ability respond to these ecologically relevant stressors in a similar manner to the Dutch strain, but are more robust at forming LTM in a low calcium environment. Despite the two populations CM and TC1 originating from different continents, LTM formation was indistinguishable in both control and stressed conditions. This indicates that the underlying mechanisms controlling cognitive differences among populations may be highly conserved in L. stagnalis.

Autor: Sarah Dalesman , Ken Lukowiak



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