Sequential Multiple Trains (using Loops within Loops)

2)  Patch Sealtest Protocol implemented

In WinLTP096, a patch-clamp Sealtest Protocol has been implemented for making easier patch-clamp gigohm seal whole-cell recordings, in particular reading out pipette resistance (Rpipette) when the electrode is in the bath, seal resistance (Rseal), when forming the seal, and series resistance (Rs), the input resistance (Rm) and the steady state DC current (Idc) when going/gone whole-cell.

  With WinLTP in the Normal Mode, to go to SealTest, click on the "SealTest AD0" or "AD1" button.  In order for these SealTest buttons to appear, AD0 and/or AD1 datatype must be in "pA" (set by the File->Edit Protocol File dialog box).

For Electrode in Bath, put the patch electrode or pipette in the bath and record the electrode or pipette resistance (Rpipette) by clicking the Electrode in Bath "Start (F5)" button (or by pressing F5).  Set the appropriate pulse amplitude in the Pulse Amp edit field.

For Form Seal, once the electrode is on the cell surface, click the "Start - Low Pulse Amp (F6)" button (or press F6) to output the low pulse amplitude pulse to approximately measure the seal resistance, Rseal.  Once the seal is coming into the Gohm range, click the "Start - High Pulse Amp (F7)" button (or press F7) to output the high pulse amplitude to accurately measure the seal resistance, Rseal.  Set the appropriate low and high pulse amplitudes in the neighboring pulse amplitude edit fields.

For Go Whole Cell (see Fig), when ready to go whole cell, click the Go Whole Cell "Start" button to record the seal resistance (Rs, in Mohms), the input resistance (Rm, in Mohms) and the steady state DC current (Idc, in pA).  Set the appropriate pulse amplitude in the Pulse Amp edit field.  Also when going whole cell, you can plot the Rs and Rm values, write the Rs and Rm values to the spreadsheet, and save the Rs/Rm sweep files to disk by checking the appropriate checkboxes.  Return to the Normal Mode Protocol by clicking "Return to Protocol" button.

For Go Whole-Cell, after the gigaohm seal has been formed and you are ready to go whole cell, click the Go Whole Cell "Start (F8) " button (or press F8) to record the seal resistance (Rs, in Mohms), the input resistance (Rm, in Mohms) and the steady state DC current (Idc, in pA) (see the figure, bottom left).  Set the appropriate pulse amplitude in the Pulse Amp edit field.  Also when going whole cell, you can plot the Rs and Rm values and them the spreadsheet by checking the “Plot and Print Rs/Rm Values” checkbox, and you can save the Rs/Rm sweep files to disk by checking the “Save RsRm Sweeps to Disk” checkbox.  Note that in Fig. 5.3.1, the “Plot and Print Rs/Rm Values” checkbox is checked, and so Rs and Rm are plotted before and after going whole-cell (see Fig. 5.3.1, top right), and the Rs and Rm values are put into the spreadsheet (see Fig. 5.3.1, bottom).

The Sweep Duration can be set between 10 and 1000 msec and repeat between 10 Hz and 1 Hz, and the test stimulation can be stopped by pressing the “Stop (F4)” button (or pressing F4).

Return to the Normal Mode Protocol by clicking "Return to Protocol" button.

3.  Rs single or double exponential curve fitting

Measuring hippocampal cell Rs by exponential curve fitting

Double Exponential (correct)

Single Exponential (incorrect)

4.  MaximumSlope Measurement

To use the MaximumSlope measurement, set the MaxSlope time field ("1 ms" in this example, marked by a red slope line) so that it is within the larger BegTime/EndTime range ("2 to 8 ms after pulse" in this example, marked by solid vertical lines on the trace).  In this example, the MaxSlope algorhythm will start at 2 ms after the pulse and calculate the value of a 1 ms slope every 0.1 ms until the EndTime point is reached at a slope between 7 and 8 ms after the pulse.  The absolute largest positive or negative slope will be the one chosen and plotted using the red slope line).

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