Collect per-subject result maps into a group_data object

Globs the per-subject statistical maps written by reduce_write_results() under dir, pairs them by subject, and builds a group_data() object for fmri_meta(). When both beta and se maps are present the result carries variance (suitable for inverse-variance meta-analysis); a beta-only result is returned otherwise.

Usage

collect_results(
  dir,
  space = NULL,
  beta_desc = "beta",
  se_desc = "se",
  format = c("nifti")
)

Arguments

dir: Directory (searched recursively) containing the written maps.
space: Optional BIDS space label to filter on (e.g. "MNI152NLin2009cAsym"); NULL takes all.
beta_desc, se_desc: The BIDS desc- labels of the effect and standard-error maps (defaults "beta" / "se").
format: Group-data backend format (currently "nifti").

Value

A group_data object.

Note

Pairing by BIDS subject requires fmrigds with BIDS-aware subject keying. Multi-file "h5" aggregation is not yet supported upstream.

Examples

if (FALSE) { # \dontrun{
tmpl <- fmri_template(onset ~ hrf(trial_type, contrasts = con), ~ run,
                      reducer = reduce_write_results(format = "nifti",
                                                     stats = c("beta", "se"),
                                                     path = "study/glm"))
run_jobs(instantiate(tmpl, manifest))
gd <- collect_results("study/glm", space = "MNI152NLin2009cAsym")
fm <- fmri_meta(gd, ~ 1, method = "fe")
} # }