>Psychtoolbox>PsychFiles

directory=FindFolder(name)
Searches the Matlab ‘path’ for the path to the named folder.
There may be no matches, one match, or multiple matches.
Each unique match appears as a row in “directory”.
If there are no matches then “directory” will be an empty matrix.
Matching ignores case.
You should DEBLANK a row of “directory” before using it.

Also see Matlab’s MKDIR, TEMPDIR, ISDIR, LOOKFOR, WHAT.
Try HELP PsychFiles.