Last data update: 2014.03.03
|
R: Simulate fMRI time series
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
See Also
simVOLfmri , simprepTemporal
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")
## Not run: plot(ts, type="l")
Results
|