Abstract

Recent in vivo intracellular measurements indicate that cortical neurons operate in a high-conductance state mainly caused by intense network activity. Biophysical models of morphologically-reconstructed neocortical neurons with thousands of random synaptic events successfully reproduce intracellular measurements and the high discharge variability. Here we compare several classes of simplified models. Experimental findings are reproduced when the high-conductance component is explicitly taken into account. In contrast to integrate-and-fire models, the high discharge variability does not depend on the balance between excitation and inhibition. We suggest that basic electrophysiological properties and irregular activity of cortical neurons in vivo can be optimally captured by high-conductance models.