A gamma function hrf model, with two parameters, based on [Boynton1996]
Parameters : | duration: float :
A: float :
tau: float :
n: int :
delta: float :
Fs: float :
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Returns : | h: the gamma function hrf, as a function of time : |
Notes
This is based on equation 3 in [Boynton1996]:
h(t) = \frac{(\frac{t-\delta}{\tau})^{(n-1)} e^{-(\frac{t-\delta}{\tau})}}{\tau(n-1)!}
[Boynton1996] | (1, 2) Geoffrey M. Boynton, Stephen A. Engel, Gary H. Glover and David J. Heeger (1996). Linear Systems Analysis of Functional Magnetic Resonance Imaging in Human V1. J Neurosci 16: 4207-4221 |
HRF based on [Polonsky2000]
H(t) = exp(\frac{-t}{\tau_1}) sin(2\cdot\pi f_1 \cdot t) -a\cdot exp(-\frac{t}{\tau_2})*sin(2\pi f_2 t)
[Polonsky2000] | Alex Polonsky, Randolph Blake, Jochen Braun and David J. Heeger. Neuronal activity in human primary visual cortex correlates with perception during binocular rivalry. Nature Neuroscience 3: 1153-1159 |