Example script showing how to simulate responses of the SOC model

Contents

Add code to the MATLAB path

addpath(genpath(fullfile(pwd,'code')));

Load some stimuli

load('stimuli.mat','images');
stimulus = images(69+[16 70]);  % pick two stimuli
stimulus = cellfun(@(x) x(:,:,1),stimulus,'UniformOutput',0);  % use just the first frame
stimulus = cat(3,stimulus{:});

Compute the response of the SOC model

% initialize
cache = [];

% here, we compute the response of the SOC model, specifying certain values for the
% parameters of the model.  the values used for the <sd>, <n>, and <c> parameters
% are matched to the typical values found in V3.
[response,cache] = socmodel(stimulus,150,[0 254 127],1.2,{37.5 -1 1 8 2 .01 2 0}, ...
                            1,.5,1.5,1/1.5,.12,.99,cache);

grid is 90 x 90, gbrsize is 14 (sd is 2.2486875016), indices is [1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 101 103 105 107 109 111 113 115 117 119 121 123 125 127 129 131 133 135 137 139 141 143 145 147 149 151 153 155 157 159 161 163 165 167 169 171 173 175 177 179]
grid is 90 x 90, gausize is 9, indices is [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90]
working....................done.

% here, we compute the responses again, but this time we set the <c> parameter to 0
[response2,cache] = socmodel(stimulus,150,[0 254 127],1.2,{37.5 -1 1 8 2 .01 2 0}, ...
                             1,.5,1.5,1/1.5,.12,  0,cache);

working....................done.

% visualize the results
figure; setfigurepos([100 100 700 300]);
for p=1:2
  subplot(2,3,(p-1)*3+1);
  imagesc(stimulus(:,:,p),[0 254]); axis image tight; colormap(gray); colorbar; title('Stimulus');
  subplot(2,3,(p-1)*3+2);
  imagesc(response(:,:,p),[0 1.5]); axis image tight; colormap(gray); colorbar; title('Response (c=0.99)');
  subplot(2,3,(p-1)*3+3);
  imagesc(response2(:,:,p),[0 1.5]); axis image tight; colormap(gray); colorbar; title('Response (c=0)');
end

Published with MATLAB® R2012b