ET_PDToolkit/PDToolkit/@PDTrial/prf.m

25 lines
782 B
Matlab

function[obj h] = pupil_response_function(obj, t, n=10.1, t_max=930, f=1/(10^27))
%% Hoeks and Levelt, Behavior Research Methods 1993, vol 25(1) pp 16-26:
%
% Parameters of the Erlang Gamma are n, t_max
% # n+1 = number of laters
% # t_max = response maximum
% # f = scaling factor
%
% Erlang Gamma = Gamma distribution with shape parameter (k) set to an integer
% For more information, see: https://en.wikipedia.org/wiki/Erlang_distribution
%
% Hoeks and Levelt reported for n a range of 10.1 +/- 4.1,
% NB: They question the use of 10.1 as a value for all subjects,
% but following deconvolution this is a minor issue.
%
% t_max value reported in H&L : 930 ms with a standard deviation of 190
% ms.
%
h = f.*(t.^n) .* exp(-n .*t ./ t_max);
h(0) = 0;