Activity-dependent current distributions in model neurons.

The electrical activity of a neuron can affect its intrinsic physiological characteristics through a wide range of processes. We study a computer-simulated multicompartment model neuron in which channel density depends on local Ca2+ concentrations. This has three interesting consequences for the spatial distribution of conductances and the physiological behavior of the neuron: (i) the model neuron spontaneously develops a realistic, nonuniform distribution of conductances that is linked both to the morphology of the neuron and to the pattern of synaptic input that it receives, (ii) the response to synaptic input reveals a form of intrinsic localized plasticity that balances the synaptic contribution from dendritic regions receiving unequal stimulation, and (iii) intrinsic plasticity establishes a biophysical gain control that restores the neuron to its optimal firing range after synapses are strengthened by "Hebbian" long-term potentiation.