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INSTRUMENT OPERATION
Axopatch 200B, Copyright 1997-1999, Axon Instruments, Inc.
MODE TELEGRAPH OUTPUT
Provides a series of voltages that can be read by the computer to determine the
setting on the MODE switch. The voltages and their associated switch settings are
as follows:
I-CLAMP I-CLAMP
Mode: TRACK V-CLAMP I = 0 NORMAL FAST
Scaled Output: I I V
m
V
m
V
m
Telegraph (volts): 4 6 3 2 1
SCALED OUTPUT
Provides the current (filtered and scaled) in V-CLAMP and TRACK modes or the
membrane voltage (filtered and scaled) in I-CLAMP modes. This BNC is
duplicated on the front and back panels. On the front panel, two LEDs specify
whether the output is current (I) or membrane voltage (V
m
). The current gain is
α
βmV/pA. The voltage gain is
α
mV/mV.
10 V
m
OUTPUT
Provides the membrane voltage multiplied by ten (x10) for use in current-clamp
experiments.
In V-CLAMP mode, 10 V
m
is ten times the command potential. If the pipette
current is zero, or if the series resistance correction is 100%, the command
potential is identical to the actual membrane potential. The actual membrane
potential is given by the following equation:
10 V
m
(100 -
CORR
)
Actual Membrane Potential (mV) =
_______ _ ________
I R
s
10 100
where I = pipette current in nA
CORR = % correction set on SERIES RESISTANCE
CORRECTION control
R
s
= resistance in MΩ set on SERIES RESISTANCE control
In TRACK mode, 10 V
m
is ten times the actual potential.
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