Laterality issue on fMRI image

The laterality issue: different software will interpret fMRI images in different way (mainly refer to right/left side display), so will the functions offered by them. NIFTI toolbox provides series explanations on the issued. Here are some notes.

Definition of LEFT and RIGHT
If the display does not have labels, we define LEFT as the Left-Hand-Side
of the Axial view, and RIGHT as the Right-Hand-Side of the Axial view.
RAS (neurological convention): left cerebral hemisphere is at LEFT and
right cerebral hemisphere is at RIGHT;
LAS (radiological convention): right cerebral hemisphere is at LEFT and
left cerebral hemisphere is at RIGHT;
If the display has labels, note will be added to bring your attention.

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Laterality case in common softwares

Software	Input format	Input laterality	Input display	Output format	Output laterality
SPM5/later	ANALYZE	RAS	LAS	NIfTI	LAS
SPM5/later	ANALYZE	LAS	RAS	NIfTI	RAS
MRIcro	ANALYZE	RAS	RAS	ANALYZE	RAS
MRIcro	ANALYZE	LAS	LAS	ANALYZE	LAS
MRIcron	ANALYZE	RAS	RAS	NIfTI	RAS
MRIcron	ANALYZE	LAS	LAS	NIfTI	LAS
load/save/view_nii	ANALYZE	RAS	RAS	NIfTI	RAS
load/save/view_nii	ANALYZE	LAS	LAS	NIfTI	LAS
load/save_untouch_nii	ANALYZE	RAS	N/A	ANALYZE	RAS
load/save_untouch_nii	ANALYZE	LAS	N/A	ANALYZE	LAS

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Interpret laterality using load_nii command

1. NIfTI toolbox never saves any file with sform = qform = 0. When you see that sform = qform = 0 in the structure that is loaded by "load_nii.m", it only means that the affine matrix has been properly interpreted. As a matter of fact, the file written by "save_nii.m" is always a NIfTI file with sform = 1 and qform = 0, and you can always check the real header information stored in any NIfTI (ANALYZE) file by using "load_untouch_nii.m". In other words, you can never save your data to a NIfTI file with sform = qform = 0.
   If you want to save your data to an ANALYZE format, you can do so by using "save_untouch_nii.m". In that case, there is neither sform nor qform in the
   ANALYZE header.
2. Many other software assume that ANALYZE files are in neurological convention (RAS). Because there is really no orientation information stored in ANALYZE header, the laterality of an ANALYZE file is all based on the assumption.