CinePlex v3 Manual - Plexon Inc

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or clear the Write? checkboxes for any markers that should be exported or
not exported into the new PLX file. Click Export! to write the file.
4.6.4 Freeze Detection
CinePlex Studio can detect freeze behavior using recorded data with the Motion
Measure option. The user may define a new interval that occurs whenever a rat
freezes. The user may set a threshold level for the motion measure and define a
freeze to be whenever the motion measure falls below that level. The user may
then export the freezing episodes to a text file.
The procedural approach here is to use the Levels Editor to define the freezing
threshold and apply it to the Motion Measure data generated by CinePlex Studio,
and then import it into CinePlex Editor as the “Centroid Motion” Scalar marker.
This generates occurrences of a newly labelled “Rat Froze” marker. The user may
then export this marker to a text file.
Detecting freezing behavior
1 Define a new Interval marker (see “Defining a New Marker” on
page 169). Label it “Rat Froze”. From the Define New Marker dialog box,
click Generate Occurrences. This opens the Levels Editor dialog box,
which is described in detail in “Using the Levels Editor” on page 185.
2 In the Levels Editor dialog box, make sure to select the “Centroid Motion”
variable in the Scalar Marker To Use list. The display window opens showing
the Centroid Motion values over the duration of the file.
3 Click Center Lev 1 to get the line to the middle of the display window. Adjust it
to a reasonable freeze threshold.
4 Since we want to generate intervals when the “Centroid Motion” value falls
below the threshold, click Below from the list in the first Abv/Blw column for
the “Rat Froze” line in the grid.
5 Click Generated Selected because we only have one Level Interval marker
and it is selected. Click Done.
The Marker Occurrences window and the Activity window now show the
new “Rat Froze” intervals.
6 To write the intervals to a text file, from the File menu, select Export Markers.
In the Export Marker Data dialog box, accept the default settings, which
produce a reasonable output file. The user may change the Delimiter to use
between values, select Export a Row of Column Headers, and clear some
of the checkboxes under What to Export for Each Marker Occurrences.
For a more information, see “Export Markers” on page 239. Type a file
204 CinePlex