Thanks Andy, much appreciated. The readme that is distributed with the "IBSR_V2.0 skull-stripped NIfTI" download doesn't list the ages, but I see now that the other readme file does - sorry for missing that. So in this case I'm guessing that "JUV" stands for "juvenille"? Are these ages just unknown, or are they a catch all for some range under 7 years? We're doing work related to creation of age-appropriate MRI templates and evaluating the errors caused by use of segmentation priors from very different ages, so you can see how detailed age info would be crucial. Also, is there an easy way to translate the IBSR20 images into NIFTI format? As those images seem to be from a more homogenous age range than the IBSR18, those might also be quite useful. It's great that you guys have put together this resource for the neuroimaging community, it's very helpful!
All the best,
Paul