simTSfmri: Simulate fMRI time series
In neuRosim: Simulate fMRI Data

simTSfmri

R Documentation

Simulate fMRI time series

Description

Simulates an fMRI time series for the specified design and noise type.

Usage

simTSfmri(design = list(), base=0, nscan = NULL, TR = NULL, SNR=NULL,
	 noise = c("none", "white", "temporal", "low-frequency", 
	"physiological", "task-related", "mixture"), type = c("gaussian", "rician"),
	 weights, verbose = TRUE, rho = 0.2, freq.low = 128, freq.heart = 1.17, 
	freq.resp = 0.2, vee=1)

Arguments

`design`	List generated by `simprepTemporal` specifying the design. If not specified, noise time series are generated.
`base`	Baseline value of the time series.
`nscan`	Number of scans.
`TR`	Repetition time in seconds.
`SNR`	Signal-to-noise ratio of the time series.
`noise`	Type of noise (white is default).
`type`	If `noise==white`, `noise==task-related` or `noise==mixture`, type of system noise (gaussian is default).
`weights`	If `noise==mixture`, vector of weights with 5 elements to specify the fraction of the noise components.
`verbose`	Logical indicating if warnings should be returned.
`rho`	If `noise==temporal` or `noise==mixture`, value of autocorrelation coefficients. The length of the vector indicates the order of the autoregressive model.
`freq.low`	If `noise==low-frequency` or `noise==mixture`, frequency of the low-frequency drift in seconds.
`freq.heart`	If `noise==physiological` or `noise==mixture`, frequency of heart rate in Hz.
`freq.resp`	If `noise==physiological` or `noise==mixture`, frequency of respiratory rate in Hz.
`vee`	If `type=="rician"`, non-centrality parameter of the distribution.

Value

A vector representing the fMRI time series.

Author(s)

M. Welvaert

Examples

design <- simprepTemporal(totaltime=200, onsets=seq(1,200,40), 
	durations=20, effectsize=1, TR=2, hrf="double-gamma")
ts <- simTSfmri(design=design, SNR=1, noise="white")
plot(ts, type="l")

neuRosim documentation built on Oct. 18, 2023, 5:09 p.m.