neuRosim (version 0.2-14)

canonicalHRF: Double-gamma Haemodynamic reponse function

Description

Specifies a double-gamma variate haemodynamic response function for the given time vector and parameters.

Usage

canonicalHRF(x, param = NULL, verbose = TRUE)

Value

Vector representing the values of the function for the given time vector and parameters.

Arguments

x

Time vector in seconds.

param

List of parameters of the haemodynamic response function. The list should contain the following:

a1

Delay of response relative to onset (default: 6)

a2

Delay of undershoot relative to onset (default:12)

b1

Dispersion of response (default:0.9)

b2

Dispersion of undershoot (default:0.9)

c

Scale of undershoot (default:0.35)

verbose

If TRUE, warnings are displayed.

Author

M. Welvaert

References

[1] Friston, KJ, Fletcher, P, Josephs, O, Holmes, AP, Rugg, MD and Turner, R (1998). Event-related fMRI: Characterising differential responses. NeuroImage, 7, 30-40.

[2] Glover, GH (1999). Deconvolution of impulse response in event-related BOLD fMRI. NeuroImage, 9, 416-429.

See Also

gammaHRF, balloon

Examples

t <- 1:100
out <- canonicalHRF(t, verbose=FALSE)
rm(out, t)