Construct a Baseline Model — baseline

Builds a baseline model to account for noise and non-event-related variance. This model may include a drift term, a block intercept term, and nuisance regressors.

Usage

baseline_model(
  basis = c("constant", "poly", "bs", "ns"),
  degree = 1,
  sframe,
  intercept = c("runwise", "global", "none"),
  nuisance_list = NULL
)

Arguments

basis: Character; type of basis function ("constant", "poly", "bs", or "ns").
degree: Integer; degree of the spline/polynomial function.
sframe: A sampling_frame object.
intercept: Character; whether to include an intercept ("runwise", "global", or "none"). Ignored when basis == "constant" because the drift term already provides the constant baseline.
nuisance_list: Optional list of nuisance matrices or data frames (one per fMRI block).

Value

An object of class "baseline_model".

Examples

sframe <- fmrihrf::sampling_frame(blocklens = c(100, 100), TR = 2)
bmod <- baseline_model(basis = "bs", degree = 3, sframe = sframe)
bmod_global <- baseline_model(basis = "bs", degree = 3, sframe = sframe, intercept = "global")
bmod_nointercept <- baseline_model(basis = "bs", degree = 3, sframe = sframe, intercept = "none")
stopifnot(ncol(design_matrix(bmod)) == 8)