We are carrying out an fMRI study for 3-year-olds (from a non-standard international population) and are currently evaluating our options for creating both surface and volumetric templates without any adult reference templates. We have thoroughly read the FreeSurfer wiki, and the template creation steps in FreeSurfer always seem to involve adult priors. Our problem with this is that we are unsure if it might bring bias into our analysis.
We are thinking about these questions and would appreciate any input:
- Is it possible to create the surface template for FreeSurfer without the adult reference image (and how complex, it terms of time and effort, would it be)?
- How large would you expect the bias to be if using a study specific template using the standard FreeSurfer process (using adult priors)?
- Is it possible to create a volumetric template for children without an adult reference image (ANTs template construction e.g. starts with an initial template)?
- What would the bias/effect be if creating a pediatric volumetric template by starting with an adult template?