Quantitative Analysis Linking Inner Hair Cell Voltage Changes and Postsynaptic Conductance Change: A Modelling Study

Figure 10

Presynaptic calcium and postsynaptic conductance voltage dependence. (a) Average rate of vesicle release (vesicles per millisecond) when presented with a 100 ms depolarising voltage pulse of varying strength. Note that the blue lines represent ribbon tethered vesicles while the red lines represent free floating vesicles being released. Clearly the presence of the synaptic ribbon facilitates an almost linear release of vesicles and thus the ability to separate different voltage levels. (b) A histogram of all released vesicles’ diameters during this analysis. The model randomises the diameter of a released vesicle by fitting a normal distribution with a mean diameter of 35 nm and a SD of 10 nm [41, 56]. (c) The superimposed result of a number of simulation runs (between 30 and 40 repetitions) where 100 ms depolarising voltage pulses of varying strength were used. The red line shows the normalised presynaptic calcium current, while the blue line shows the normalised postsynaptic conductance change. Both agree with published results [11, 52, 57].

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