Lesson 12 - Surface analysis of data

In this lesson you will be demonstrated a further possibility of graphical data analysis in Wintrack which also relies on custom variable definition files. Using file drag and drop, you will generate a surface plot which illustrates spatial preferences during the probe trial of a Morris watermaze experiment.

Running the analysis...

1. Select Close All from Wintrack's Window menu to close all open documents. Do not save documents if you are asked to do so. Load the custom setup file POOL1.WSP which you find in the WINTRACK directory of your hard disk.
2. Next, you must open your WINTRACK folder, so you can examine its content. You may achieve this using Windows™ Explorer. Arrange the folder window and the Wintrack program window on your screen in such a way that the folder window is in the foreground without completely covering the Wintrack program window.
3. In the WINTRACK folder, select the sample files SWIM1.WTR through SWIM5.WTR. Drag the selected files to the Wintrack program window and drop them onto any part of it. A menu pops up from which you should select the option Analyze…
4. The Open Case Document dialog pops up. Select the option minimize and click Ok.
5. Next, the Analyze Case Document dialog pops up:
   • In the dialog field labeled Variable definition, select the option from custom file.
   • Press the button which is associated to the option from custom file in order to open a Windows™ standard File Open dialog box. Pick the file SURFACE1.VDF in the WINTRACK directory and click Ok.
   • Set the dialog field labeled Report to merge.
   • In the dialog field labeled Trial range and blocks, enter 19 for range. This restricts the analysis to trial 19 which is the probe trial.
   • Click Ok to close the dialog box and start the analysis.
6. Wintrack processes SURFACE1.VDF for all dropped case documents and successively adds the results to a newly created scrollsheet.
7. Click the New Surface Document button of the toolbar while pressing and holding down the Shift key. The New Surface Document dialog is displayed:
   • In the dialog field labeled Surface name prefix, enter Example.
   • In the dialog field labeled Window, select the option fit to data.
   • Click Ok to close the dialog box and create the surface document.
8. The Surface Properties dialog is displayed:
   • In the dialog field labeled Color scheme, select the option rainbow.
   • In the dialog field labeled Scale, select the option auto with centered mean.
   • Click Ok to close the dialog box and display the surface document.

The scrollsheet which you generated in this lesson has 4 columns and 81 rows. For the analysis, the arena is divided up into 9x9 square tiles. Each tile is represented in the scrollsheet by one row. The first two columns, xpos and ypos, indicate the tile position. The column vtimSE indicates the time spent in each tile, relative to the amount of time expected by chance. The column ntimSE indicates the number of cases contributing to the value in the corresponding time. Because the analysis is a compilation of 5 cases, the values in this column are 5 or less. Together, the last two columns of the scrollsheet are an example for a surface variable, here called timSE. In the surface document you have just created, each tile corresponds to a row of the scrollsheet and its color represents the respective value of the timSE variable. A color scale defines the translation from variable values in the scrollsheet to tile colors in the surface document. The surface variable timSE is defined in the custom variable definition file SURFACE1.VDF which we are going to inspect below.

The syntax of the custom variable definition file...

1. Run Windows™ NotePad and open the file SURFACE1.VDF. The structure of the file is similar to the one you have seen before. However, it also contains a new statement:

   Surface variable, example 1
   
   [variables]
   
   Matrix Data=Time
   Include Rule=All 
   Surface Tgt=s1 Xres=9 Yres=9 Field=Arena Range=1-30 Goal=NE Mode=Ratio
   Tabulate Sce=s1 Name=timSE Fmat=2 Cmnt=[s]
   
   [end]

   • All text above [variables] is free commentary. Between [variables] and [end] are the statements which define the sequence of analysis. You are already familiar with the Matrix, Include and Tabulate statements.
   • The Surface statement is new. It computes a data surface called s1 (Tgt=s1) using the current data matrix of Time values. This data surface covers the entire arena (Field=Arena) and is divided up into 9x9 square tiles (Xres=9, Yres=9). Cell values of the data matrix are mapped to the surface using the xy position coordinates of the respective data points in order to determine the time spent in each tile. Range=1-30 instructs Wintrack to merge all 30 trials of each case when computing the data surface. However, in the Analyze Case Document dialog we have entered 19 in the respective dialog field to restrict this potential range to the probe trial which is trial 19. As indicated by Goal=NE, all trials are first virtually rotated to move the goal is to the NE quadrant. This feature allows meaningful merging of trials and cases even if the goal positions are not identical. Mode=Ratio triggers a transformation which divides the time spent in each tile by the time expected there by chance. Thus, values >1 indicate a preference for the respective part of the arena.
2. When you are done studying the text, terminate Windows™ NotePad and return to Wintrack. There, close all open documents by selecting Close All from the Window menu. Do not save documents if you are asked to do so.

Lesson 13 - Wintrack macros will introduce Wintrack macros, the most powerful, but also most complicated feature of Wintrack.