Measuring Input Resistance: Ramps vs pulses

[Trent A. Basarsky]

Hello,

I have noticed that some labs measure input resistance as the inverse
of the slope from a ramp voltage command, while others measure it simply
as the quotient of voltage divided by the steady state current in response
to a square pulse.  I am referring to measuring input resistance in 
astrocytes.

Does anyone have some insight on what the advantages or disadvantages of either
of these techniques are?  I am curious as to whether either of these techniques
are more senstive, or possibly less prone to error.

Any info appreciated. E-mail preferred.

Thank you
Trent


_______________________________________________________________
Trent A. Basarsky                      Internet :  tab at iastate.edu
Dept. of Zoology and Genetics          Voice :  (515) 294-4054
Iowa State University
Ames, Iowa 50011