ROI Toolbox Docs

Documentation: Movement Parameters (plot_move.m)
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Jeff Cooper
12/10/02

1. Summary

plot_move.m is a simple script designed to allow easy viewing of a
subject’s movement parameter file, as generated by SPM’s Realign
facility.  Given a movement parameter file, the script displays 
that text file broken into two viewing windows: one which displays
a plot of the subject’s x, y and z movement in mm, and one which
displays a plot of the subject’s pitch, roll, and yaw movement in
radians.  Both windows are plotted vs. time, as measured in scans.


2. Usage

plot_move

This script takes no inputs; it runs only in a graphical interactive
mode.  When run, the user is queried for a realignment parameter text
file, as generated by SPM’s Realign facility.  This text file must 
be formatted in a particular way, or else an error will be generated;
the file is generally generated on a session-by-session basis, one for
each session of a subject’s scan, and generally appears in the same
directory as the functional images for that session.  The text file
stores the parameters in six columns, with as many rows as there are
images in that session.  The first three columns of the file store 
the x, y, x, movements, while the second three store the pitch, roll, 
yaw movements at each TR.
	Once given this text file, the script pops up a figure divided
into two viewing windows.  The upper window plots the subject’s x, y
and z movements in mm, and the lower window plots the subject’s pitch,
roll and yaw movements in radians, although the scale for the lower
window may be difficult to see.  
       Both windows have legends labeling each line with the according 
movement, and the lower window’s legend also contains the max and min 
values for that plot, so that the scale is more obvious.  These legends 
have a way of appearing in the most inconvenient spot, but they can be 
easily picked up and moved out of the way with the mouse.
	The y-axis scale for both plots is displayed on the left side; the
x-axis scale for both plots is identical and in scans.  This allows easy 
identification of movements significant in both translational and
rotational terms.
	The script can be closed by closing the viewing window in the normal
way. 


3. Output

None.


4. Last Bits

plot_move.m was written as part of the Gabrieli Lab ROI Toolbox,
a package of utilities to examine ROI data in SPM99.  

This code is in a very fluid state of development, and any suggested
modifications are welcomed and invited.  Please contact Jeff Cooper
in the Stanford Psychology Department at jcooper@stanford.edu with 
any questions about usage, bug reports, or suggestions for further
revision.  Good luck...

