Dear Luis,
> Could anyone give me a reference of who came up with the use of a gamma
> variate function to model the HRF, and the justification?
> thank you very much,
I believe the first references for the gamma pdf were Nick Lange and Mark
Cohen. The justification is that it is "plausible" and flexible given that
it contains only two parameter, -- in comparison with the one-parameter
global Poisson model (Friston, 1994, HBM 1:153).
@Article{Lange1997NonLinear,
author = {Nicholas Lange and Scott L. Zeger},
title = {Non-linear Fourier Time Series Analysis for Human
Brain Mapping by Functional Magnetic Resonance
Imaging (with discussion)},
journal = {Applied Statistics, Journal of the Royal
Statistical Society, Series C},
year = {1997},
volume = {46},
number = {1},
pages = {1--29},
}
@Article{Cohen1997Parametric,
author = {Mark S. Cohen},
title = {Parametric Analysis of {fMRI} Data Using Linear
Systems Methods},
journal = {NeuroImage},
year = {1997},
volume = {6},
pages = {93--103},
}
Regards
Finn
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Finn Årup Nielsen, DSP IMM DTU, Lyngby, Denmark
http://hendrix.imm.dtu.dk/staff/fnielsen/
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