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Abstract:
Stochastic fluctuations of voltage-gated ion channels
generate current and voltage noise in neuronal membranes. This
noise may be a critical determinant of the efficacy of information
processing within neural systems. Using Monte-Carlo simulations, we
carry out a systematic investigation of the relationship between
channel kinetics and the resulting membrane voltage noise using a
stochastic Markov model of dendritic excitability in cortical
neurons. Our simulations show that kinetic parameters which lead to
an increase in membrane excitability (increasing channel densities,
decreasing temperature) also lead to an increase in the magnitude
of the sub-threshold voltage noise. Noise also increases as the
membrane is depolarized from rest towards threshold. This suggests
that channel fluctuations may interfere with a neuron's ability to
function as an integrator of its synaptic inputs and may limit the
reliability and precision of neural information processing.
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