>I was wondering if anyone out here in bionet.neuroscience have tried to
>implement it using discrete components to model a "single" neuron.
>Specifically, does anyone know of any commercial transistors having
>the same I-V characteristics (i.e. similar sigmoidal shape) as the
>sodium and potassium conductance described in the paper.
I did build the Mahowald & Douglas model on an analog VLSI chip a couple of
year ago, however I don't think it would be possible to reproduce their model
using discrete components.
This stems from the fact that the model relies upon analog VLSI circuits
operating in the subthreshold domain. The performance of the circuits is
tied strongly to the equations describing MOS subthreshold behavior
(specifically, the exponential relationship between current and gate voltage)
In addition, the sigmoid I-V characteristic arises not from single
transistors, but from their configuration into differential pairs and current
mirrors to form the model's Na and K channels.
Elliot Menschik Graduate Group in Neuroscience
menschik at eniac.seas.upenn.edu University of Pennsylvania
School of Medicine
Philadelphia, PA 19104