fmri.detrend: Detrend fMRI time series
In neuroconductor/fmri: Analysis of fMRI Experiments

Description Usage Arguments Details Value Author(s) References See Also Examples

Detrend fMRI dataset with a polynomial of given degree

1	fmri.detrend(data, degree = 1, nuisance=NULL, accoef = 0)

`data`	fMRI dataset of class ”`fmridata`”
`degree`	Degree of the polynomial used to detrend the data. defaults to 1 (linear trends).
`nuisance`	Matrix of additional nuisance parameters to regree against.
`accoef`	Coefficient of AR(1) model used for prewhitening. default 0.

The function can be used to detrend the time series of an fMRI dataset data (of class ”fmridata” using polynomials. If the argument degree is larger than 0 (default: 1) the polynomial trends up to the given degree are removed from the data. If the argument accoef is larger than 0 (default: 0) prewhitening using an AR(1) model is performed.

Detrended data object of class ”fmridata”.

Joerg Polzehl polzehl@wias-berlin.de

Polzehl, J. and Tabelow, K. (2007). fmri: A Package for Analyzing fmri Data, R News, 7:13-17.

fmri.lm

  # Example 1
  data <- list(ttt=writeBin(rnorm(32*32*32*107),raw(),4),
               mask=array(1,c(32,32,32)),dim=c(32,32,32,107))
  class(data) <- "fmridata"
  data <- fmri.detrend(data,2)