Current Source Density Approximations

Managing anatomically complex model cells with the CellBuilder. Importing morphometric data with NEURON's Import3D tool or Robert Cannon's CVAPP. Where to find detailed morphometric data.
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Joined: Wed May 18, 2005 10:37 pm

Current Source Density Approximations

Post by wwlytton »

Apparently there are differences in approach as to whether capacitative current should or should not be included as one of the currents that constitutes the Current Source Density (CSD) that is approximated via an inverse solution using a 2nd spatial deriv of voltages.

In reading the documentation on extracellular it was also not clear to me whether i_cap was included in i_membrane but Hines informed me that it does. This would suggest that i_cap should be incorporated in a CSD calc.

From Ted Carnevale:
It must be included. Accumulation (or depletion) of charge on the inside surface of the membrane is accompanied by accumulation (or depletion) of an equal amount of charge (but opposite in sign) on the external surface of the membrane. The external medium can't tell whether this charge movement is caused by membrane current that is capacitive or ionic, but the charge movement amounts to a current and so

(1) contributes to the extracellular potential that one would observe
(2) will be part of the total current that is calculated if one starts with recorded extracellular potential and tries to solve for the current that generated it.
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