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Stability of function and variability of conductances in a crustacean motor network| old_uid | 3643 |
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| title | Stability of function and variability of conductances in a crustacean motor network |
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| start_date | 2007/12/10 |
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| schedule | 11h30 |
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| online | no |
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| details | Invité par David Perrais |
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| summary | Computational models have demonstrated that highly similar neuronal output can be generated from disparate densities of underlying conductances. We used the stomatogastric nervous system (STNS) of the crab Cancer borealis to test the biological validity of this paradox. The Central Pattern Generator (CPG) of the STNS is located in the stomatogastric ganglion (STG) which produces the pyloric and gastric rhythms driving the movements of the stomach. This ganglion is composed of 25-30 neurons in the crab, each of these neurons being reliably identifiable from animal to animal based on their activity and projection patterns. We analyzed the properties of the pyloric rhythm in 55 animals and found the properties of the rhythm to be very stable across animals : the phase relationships between the different cell types are maintained throughout a wide range of cycle periods. Moreover, for the Lateral Pyloric (LP) neuron, the frequency of spiking during the burst is also scaling with cycle period. However, when we analyzed the pattern of expression of ion channels in different pyloric and gastric cells, we found a systematic 3-4 fold variability in the expression of potassium, sodium, and H-type channel. This was even true for two LP cells presenting an almost superimposable activity. A more thorough analysis showed that this variability is present at the single channel level, but the combined analyses of several channels (up to 6) revealed strong correlations in the level of expression of different channels. Moreover, these patterns of correlations were specific to each cell type. In conclusion, we confirmed that a same neuronal output can be generated from disparate densities of underlying conductances, and revealed that this variability might be masking a stability of quantitative relationships in the expression of channels. |
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| responsibles | Deris |
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