 phenotype NIfTI image
    based on a chosen human or mouse brain atlas. The atlas can be automatically
    resampled to match the phenotype image resolution if needed.

    Parameters
    ----------
    phenotype_nii_path : str
        Path to the input phenotype NIfTI file. Should be in MNI space for human atlases,
        or Allen CCFv3 space for mouse atlas.
    atlas_dict : dict
        A dictionary containing the following keys:

            - &#39;atlas&#39;: The loaded Mouse atlas image.
           