Analysis of complex bursting in cortical pyramidal neuron models

Burst firing is a prominent feature of cortical pyramidal cells and is thought to have significant functional roles in reliable signaling and synaptic plasticity. Modeling studies have successfully elucidated possible biophysical mechanisms underlying complex bursting in pyramidal cells. Based on these results (Pinsky, Rinzel, J. Comput. Neurosci. 1 (1994) 39-60), we have built a simplified two-compartment burst model. Using the fast- and slow-variable analysis method, we show that complex bursting is an instance of square-wave bursting, where the dendritic slow potassium conductance is the single slow variable. The coupling parameters between the two compartments change the topological class of bursting thereby altering the firing patterns of the neuron. These results explain the diverse set of firing patterns seen with different dendritic morphologies (Mainen, Sejnowski, Nature 382 (1996) 363-366). (C) 2000 Elsevier Science B.V. All rights reserved.