Mukunda, L Chinmayee and Narayanan, Rishikesh (2017) Degeneracy in the regulation of short-term plasticity and synaptic filtering by presynaptic mechanisms. In: JOURNAL OF PHYSIOLOGY-LONDON, 595 (8). pp. 2611-2637.
Full text not available from this repository. (Request a copy)Abstract
Information processing in neurons is known to emerge as a gestalt of pre-and post-synaptic filtering. However, the impact of presynaptic mechanisms on synaptic filters has not been quantitatively assessed. Here, we developed a biophysically rooted, conductance-based model synapse that was endowed with six different voltage-gated ion channels, calcium pumps, calcium buffer and neurotransmitter-replenishment mechanisms in the presynaptic terminal. We tuned our model to match the short-term plasticity profile and band-pass structure of Schaffer collateral synapses, and performed sensitivity analyses to demonstrate that presynaptic voltage-gated ion channels regulated synaptic filters through changes in excitability and associated calcium influx. These sensitivity analyses also revealed that calcium-and release-control mechanisms were effective regulators of synaptic filters, but accomplished this without changes in terminal excitability or calcium influx. Next, to perform global sensitivity analysis, we generated 7000 randomized models spanning 15 presynaptic parameters, and computed eight different physiological measurements in each of these models. We validated these models by applying experimentally obtained bounds on theirmeasurements, and found 104 (similar to 1.5%) models to match the validation criteria for all eight measurements. Analysing these valid models, we demonstrate that analogous synaptic filters emerge from disparate combinations of presynaptic parameters exhibiting weak pairwise correlations. Finally, using virtual knockout models, we establish the variable and differential impact of different presynaptic channels on synaptic filters, underlining the critical importance of interactions among different presynaptic components in defining synaptic physiology. Our results have significant implications for protein-localization strategies required for physiological robustness and for degeneracy in long-termsynaptic plasticity profiles.
| Item Type: | Journal Article |
|---|---|
| Publication: | JOURNAL OF PHYSIOLOGY-LONDON |
| Publisher: | WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA |
| Additional Information: | Copy right for this article belongs to the WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA |
| Department/Centre: | Division of Biological Sciences > Molecular Biophysics Unit |
| Date Deposited: | 20 May 2017 06:52 |
| Last Modified: | 20 May 2017 06:52 |
| URI: | http://eprints.iisc.ac.in/id/eprint/56945 |
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