Calcium-dependent subthreshold fluctuations in membrane voltage; a modeling study
© Bardakjian et al; licensee BioMed Central Ltd. 2010
Published: 20 July 2010
Membrane potential noise plays multiple functional roles in the nervous system, as described in the review by Faisal et al. Calcium-dependent potassium (KCa) channels are ion channels whose conductance depends on intracellular calcium concentration. Previous work by Diba et al suggests that such channels play a central role in subthreshold voltage noise . While most channels generate noise through their inherent thermal fluctuations, we hypothesize that KCa channels also generate low-frequency subthreshold oscillations by transmitting stochastic fluctuations in intracellular calcium.
We have produced a stochastic computer model that incorporates KCa channels and calcium dynamics into a CA3 pyramidal neuron, which is based on the biophysically realistic Traub model . To introduce channel noise, we replaced all Hodgkin-Huxley (HH) channels with equivalent Markov models . There is also an intracellular calcium pool, with Ca2+ levels that vary stochastically due to influx through Markovian calcium channels.
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