An electrophysiology quesiton

Doktor DynaSoar targeting at OMCL.mil
Tue Feb 10 00:21:07 EST 2004


I concur. EPSC = currents, ie. charge flow as opposed to potential
difference (EPSP). The measures are proportional per Ohm's Law, and
current (ion) flow is responsible for the apparent voltage changes.

The zero point is an arbitrary setting based on *not* changing cell
behavior, in order to compare with changes in behavior later; a
baseline "chosen" by the cell's own (in- or minimal) activity.


On Mon, 9 Feb 2004 19:30:01 -0400, "NMF" <nm_fournier at ns.sympatico.ca>
wrote:

} A "passive" clamp is an oxymoron.  It really means that you are clamping the
} membrane potential of the cell at its resting potential.  Therefore, you
} change the cell potential by 0 mV and thus the term "passive" clamp is used.
} It isn't really or truly a passive condition because the current you see or
} measure (the EPSC) is the actual the current the voltage amplifier had to
} deliver to maintain the cell at fixed potential.
} 
} Hope that helps,
} 
} Neil
} 
} "Xiaoshen Li" <xli6 at gmu.edu> wrote in message
} news:c08fgr$pm9 at portal.gmu.edu...
} > Hi,
} > I have an electrophysiology question. I read somewhere "somatic EPSCs
} > under passive voltage clamp conditions...". What is "passive voltage
} > clamp"? I am always confused EPSC and EPSP. In voltage clamp condition,
} > are we measuring EPSCs?
} >
} > Thank  you very much for your help.
} >
} > Best Regards,
} > Xiaoshen
} >
} 




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