Simplified models of neocortical pyramidal cells preserving somatodendritic voltage attenuation

Simplified models are needed for performing large-scale network simulations involving thousands of cells. Ideally, these models should be as simple as possible, but still capture important electrotonic properties, such as voltage attenuation. Here, we propose a method to design simplified models with correct voltage attenuation, based on camera-lucida reconstructions of neurons. The simplified model geometry is fit to the detailed model such that it preserves: (i) total membrane area, (ii) input resistance, (iii) time constant and (iv) voltage attenuation for current injection in the soma. Using the three dimensional reconstruction of a layer VI pyramidal cell, we show that this procedure leads to an efficient simplified model which preserves voltage attenuation for somatic current injection as well as for distributed synaptic inputs in dendrites. Attenuation was also correctly captured in the presence of synaptic background activity. These simplified models should be useful for performing network simulations of neurons with electrotonic properties consistent with detailed morphologies.