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initially used the same parameters as previously published by [4]. Accordingly, membrane capacitance was set at 1.64 pF/cm2, membrane resistance (Rm) was 0.44 kΩ⋅cm2 in the soma and 110 kΩ⋅cm2 in the dendrites, and axial resistance was given a value of 250 kΩ⋅cm. With these parameters we obtained a τ) of 46 ms and an Rm of 12.6 MΩ, which is almost identical to the values of 46 ms and 12.9 MΩ reported by [4]. However, initial simulations with active membrane showed that it was not possible to reproduce the characteristic firing pattern of Purkinje cells with these membrane parameters. In particular, the low Rm value in the soma caused a huge current sink, so that the model could not fire somatic Na+ spikes. For this reason the model presented here had an Rm of 10 kΩ⋅cm2 in the soma and 30 kΩ⋅cm2 in the rest of the cell, which are comparable with values for Rm in other neuron models [2]. This model had an Rmof 19.6 MΩ under conditions of simulated external Cs+ block (i.e., Kdr, KM, and Kh channels blocked; [1]) which is a realistic Rm value for Purkinje cells in slice [3].
[1] B Hille. Ionic Channels of Excitable Membranes. Sunderland MA: Sinauer, 1991.
[2] WR Holmes and W Rall. Electrotonic models of neuronal dendrites and single neuron computation. In T McKenna, J Davis, and S Zornetzer, editors, Single Neuron Computation, pages 7–25. NY: Academic, 1992.
[3] RR Llinás and M Sugimori. Electrophysiological properties of in vitro Purkinje cell somata in mammalian cerebellar slices. Journal of Physiology (Lond.), 305:171–195, 1980.
[4] M Rapp, Y Yarom, and I Segev. The impact of parallel fiber background activity on the cable properties of cerebellar Purkinje cells. Neural Computation, 4:518–533, 1992.