Aye, there's the rub. Some available ones have artificial brightness patterns and things.
I might try out these MNI McGill infant templates:
https://nist.mni.mcgill.ca/infant-atlases-0-4-5-years/
to start. I am a little surprised they are not sharper/crisper. The package name is a bit confusing, I think, since they don't have reference atlases (= ROI maps) associated with them, which might also be slightly difficult for analysis.
NB: when downloading the zipped dir of NIFTIs, note that they just unpack into your current working directory, not into a subdirectory of the basename of the zipped archive. Grumble.
--pt
