How to view averaged event responses

Note: This utility is still under development - it should ultimately give you fit statistics.

Indications:

You acquired fMRI data as a series of single event trials, and want to see the average response.
What to do:

What to do:

Type:

> Averager -i infile.ext -o outfile.ext -a ControlFile [ -I -R]

where infile.ext is the raw image file in any of our standard formats and outfile.ext is the desired output file. Note that Averager will perform in-line image type conversion, so that you can choose the output data type..

Each line of the ControlFile should contain the time point numbers (counting from 1) of images to be averaged together.

For example, if the control file reads:

1 6 11 16
2 7 12 17
3 8 13 18
4 9 14 19
5 10 15 20

the output file will contain 6 images. The first will be the average of time points 1, 6, 11 and 16, the second will be the average of time points 2, 7, 12 and 17, etc... In this example, the global average will be formed from images 1 through 20 even if the input file contains more images. The output will be scaled as percent changes from this global average.

If -R is set, the final iamge will be the average of all images in the range from the first to the last image in the control file and the averaged images in the output file will not be scaled to percent change.

Every attempt was made to be tolerant of aberrations in the controlfile. Nevertheless, it is strongly recommended that the numbers be separated only by tabs or spaces, that only numbers appear, and that each line ends with a carriage return.

By default, the output files will be expressed as percent signal change referred to the global average of the data, from the first to the last time point.

**Options**
-I	Force output data type to short integer, if saving as analyze (.img) file types. This is NOT* recommended unless the -R option is set, as the data range may be made too small to be useful.
-R	The output file will be kept in its (raw) original unscaled units, and a final image will be appended that is the average of all images from the first to the last in the control file.

The full source for Averager can be found [HERE]

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This page is maintained by Mark Cohen [updated 4.16.02]