function defineGlobals()
%define global constants
global SVMCROSSVAL_USE_DRIVE_CHECK_HACK;
%enables subroutine to check if image path starts with 'D'
SVMCROSSVAL_USE_DRIVE_CHECK_HACK                  = 1;  

global SVMCROSSVAL_CROSSVAL_METHOD_DEF;
% supported classification methods
SVMCROSSVAL_CROSSVAL_METHOD_DEF.svmcrossval       = 'svm crossval';
SVMCROSSVAL_CROSSVAL_METHOD_DEF.classPerformance  = 'svm class performance';
SVMCROSSVAL_CROSSVAL_METHOD_DEF.crossSubject      = 'svm across subject testing';
SVMCROSSVAL_CROSSVAL_METHOD_DEF.somTraining       = 'som Training';

global SVMCROSSVAL_VOXEL_SELECTION_MODE_DEF;
% supported voxel selection methods
SVMCROSSVAL_VOXEL_SELECTION_MODE_DEF.manualGui    = 'manually defined in GUI';
SVMCROSSVAL_VOXEL_SELECTION_MODE_DEF.roiImage     = 'use ROI image by pop-up image selector';

global SVMCROSSVAL_SUBJECT_PREFIX;
% internally used to prefix subject-ids starting with numbers.
SVMCROSSVAL_SUBJECT_PREFIX                        = 'subject';
end