# basisFunctions: Informed basis set In FIACH: Retrospective Noise Control for fMRI

## Description

This function produces the impulse response for the canonical haemodynamic response function and its derivatives in time and space at a desired sampling rate.

## Usage

 `1` ```basisFunctions(RT,orth=TRUE) ```

## Arguments

 `RT` RT is the time between samples. It must be specified in seconds (e.g. 1/16). `orth` Boolean describing whether or not the basis should be orthogonalised.

## Value

A matrix is returned containing all three impulse responses.

Tim Tierney

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19``` ```RT=1/16 basis<-basisFunctions(RT=RT) basis<-basis/max(basis) x<-seq(0,32,RT) ylim<-c(min(basis)-sd(basis),max(basis)+sd(basis)) plot(x,basis[,1],lwd=7,col="red",type="l", main="Informed Basis Set",xlab="Time(seconds)", ylab="Intensity(A.U.)",ylim=ylim) y<-seq(min(ylim),max(ylim),length.out=10) abline(h=y,col="grey") legend(x="topright", legend=c("Canonical HRF", "Temporal Derivative", "Dispersion Derivative"), col=c("red","blue","green"),lwd=2) lines(x,basis[,1],lwd=7,col="red") lines(x,basis[,2],lwd=7,col="blue") lines(x,basis[,3],lwd=7,col="green") ```

FIACH documentation built on May 1, 2019, 8:02 p.m.