fmri (version 1.7-2)

fmri.detrend: Detrend fMRI time series

Description

Detrend fMRI dataset with a polynomial of given degree

Usage

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

Arguments

data

fMRI dataset of class ''fmridata''

degree

Degree of the polynomial used to detrend the data. defaults to 1 (linear trends).

accoef

Coefficient of AR(1) model used for prewhitening. default 0.

Value

Detrended data object of class ''fmridata''.

Details

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.

References

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

See Also

fmri.lm

Examples

# NOT RUN {
  # 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)
# }