ACTIVITY-DEPENDENT CURRENT DISTRIBUTIONS IN MODEL NEURONS

The electrical activity of a neuron can affect its intrinsic physiolog ical characteristics through a wide range of processes. We study a com puter-simulated multicompartment model neuron in which channel density depends on local Ca2+ concentrations. This has three interesting cons equences for the spatial distribution of conductances and the physiolo gical behavior of the neuron: (i) the model neuron spontaneously devel ops a realistic, nonuniform distribution of conductances that is linke d 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 cont ribution from dendritic regions receiving unequal stimulation, and (ii i) intrinsic plasticity establishes a biophysical gain control that re stores the neuron to its optimal firing range after synapses are stren gthened by ''Hebbian'' long-term potentiation.