Multichannel Systems Roboocyte2 Manual - Manual (Page 101)

Analysis with Roboocyte2+
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Drift Correction
The two cursors appearing in green color are used for correcting a (linear) drift of the holding
current. To do so, current values at the two cursor positions are measured, a straight line is
calculated and subtracted from the original current trace. To perform a drift correction, you
should move both cursors to a position representative for the linear drift, typically but not
necessarily at the beginning and end of the current trace, or before and after the ligand
application. Then, you can activate the drift correction by the check box "Drift Correction"
and the drift will be more or less compensated.
Without Drift Correction With Drift Correction
Now, you can move the cursors around to get an optimal correction; the current trace will
be updated automatically according to the position of the cursors.
Baseline Subtraction
In addition to drift correction, a baseline subtraction often makes sense. For example, if you
record ligand gated ion channels, a baseline subtraction will cause a read-out from the ROI which
represents the ligand gated ion channel current unbiased by the leak current. Taking the example
shown in the last figure, a leak current of about -70 nA remains after drift correction. Activating
the baseline subtraction subtracts the baseline current and the current trace runs close to 0 nA
at the baseline cursor position.
Without Baseline Subtraction With Baseline Subtraction
For performing baseline subtraction, the average current between the baseline cursors is
calculated and subtracted from the current trace.