Convert a NeuroVec to GDS

Import a neuroim2::NeuroVec (4D brain volume) as a GDS object. The 4th dimension can represent subjects OR contrasts.

Usage

# S3 method for class 'NeuroVec'
as_gds(
  x,
  assay_name = "beta",
  along = c("subject", "contrast"),
  subjects = NULL,
  contrasts = NULL,
  mask = NULL,
  ...
)

# S3 method for class 'DenseNeuroVec'
as_gds(
  x,
  assay_name = "beta",
  along = c("subject", "contrast"),
  subjects = NULL,
  contrasts = NULL,
  mask = NULL,
  ...
)

Arguments

x

A neuroim2::NeuroVec object.

assay_name

Name for the assay (default: "beta").

along

What does the 4th dimension represent? One of:

• "subject": Each volume is a different subject (single contrast)

• "contrast": Each volume is a different contrast (single subject)

subjects

Character vector of subject IDs. Length must match the 4th dimension when along = "subject", or length 1 when along = "contrast".

contrasts

Character vector of contrast names. Length must match the 4th dimension when along = "contrast", or length 1 when along = "subject".

mask

Optional mask. See as_gds.NeuroVol for options.

...

Additional arguments passed to new_gds().

Value

A gds object with voxel space.

Examples

if (requireNamespace("neuroim2", quietly = TRUE)) {
  sp4 <- neuroim2::NeuroSpace(c(4, 4, 2, 3), spacing = c(2, 2, 2))
  vec4d <- neuroim2::NeuroVec(array(rnorm(96), c(4, 4, 2, 3)), sp4)

  # 4D volume where each volume is a subject
  gds_obj <- as_gds(vec4d, along = "subject",
                    subjects = c("sub-01", "sub-02", "sub-03"))
  print(subjects(gds_obj))

  # 4D volume where each volume is a contrast
  gds_obj <- as_gds(vec4d, along = "contrast",
                    contrasts = c("faces", "places", "objects"))
  print(contrasts(gds_obj))
}
#> [1] "sub-01" "sub-02" "sub-03"
#> [1] "faces"   "places"  "objects"