WinLTP
Version 2.20b
Leading-Edge Features
Special Features
Ordinary Features
Additional Features
Sweeps can be Signal Averaged, Stimulus Artifact Blanked, or Digitally Filtered Online
 

In addition to capturing and analyzing raw sweeps, the WinLTP can also do on- and off-line signal averaging of these sweeps, blank out the stimulus artifacts if required, and low-pass filter the sweeps.  Signal averaging occurs first, then stimulus artifact blanking, and finally low pass filtering.

Single raw sweeps can either be (i) low-pass filtered, (ii) stimulus artifact blanked, or (iii) stimulus artifact blanked and then filtered (top part of the figure below), but not first filtered and then stimulus artifact blanked.  The insets show a patch-clamp recording of an EPSC from one raw sweep (left trace) showing substantial noise and a large stimulus artifact at the left of the trace, the sweep that has been digitally filtered to reduce the noise (note the large filtered artifact, right top trace), the sweep with the stimulus artifact removed (middle trace), and the stimulus artifact blanked sweep that has then been filtered (right bottom trace).

Alternatively, raw sweeps can first be (i) signal averaged, then this signal averaged sweep can either be (ii) low-pass filtered, (iii) stimulus artifact blanked, or (iv) stimulus artifact blanked and then filtered (bottom part of the figure below), but not first filtered and then stimulus artifact blanked.  The insets show EPSCs from two raw sweeps showing substantial noise and a large stimulus artifact (left traces), the signal averaged sweep also with a large stimulus artifact (2nd trace) obtained from averaging the two raw sweeps, the signal averaged sweep that has been digitally filtered (right top trace), the signal averaged sweep has had the stimulus artifact removed (3rd trace), and the averaged, stimulus artifact blanked sweep that that has been filtered (right bottom trace).

For more information see Section 4.5 in the on-line WinLTP Manual.

  

All these traces can be shown on the screen and saved to a data file.  Calculations of slopes and peaks are made on the latest processed sweep.  For example, if signal averaging, stimulus artifact blanking and digital filtering are being used, then the averaged, blanked and filtered sweep is the one that will be analyzed.