Calculate initial values of current variance parameter for source connectivity estimation Input: bayesinitfile : Bayes file.(.bayes.mat) brainfile : Cortical model file(.brain.mat) dmri_file : diffusion MRI file(.dmri.mat) bsnorm : Normalization constant of lead field matrix a_min : Minimum value of current variance parameter (= vb_parm.a_min) Output: a_init [~1840 x 1] Initial values of current variance parameter (= vb_parm.a) 2015/01/29 M.Fukushima Copyright (C) 2011, ATR All Rights Reserved. License : New BSD License(see VBMEG_LICENSE.txt)
0001 function [a_init] = vb_calc_initialvalue_a... 0002 (bayesinitfile, brainfile, dmri_file, bsnorm, a_min) 0003 % Calculate initial values of current variance parameter for source 0004 % connectivity estimation 0005 % 0006 % Input: 0007 % bayesinitfile : Bayes file.(.bayes.mat) 0008 % brainfile : Cortical model file(.brain.mat) 0009 % dmri_file : diffusion MRI file(.dmri.mat) 0010 % bsnorm : Normalization constant of lead field matrix 0011 % a_min : Minimum value of current variance parameter (= vb_parm.a_min) 0012 % 0013 % Output: 0014 % a_init [~1840 x 1] 0015 % Initial values of current variance parameter (= vb_parm.a) 0016 % 0017 % 2015/01/29 M.Fukushima 0018 % 0019 % Copyright (C) 2011, ATR All Rights Reserved. 0020 % License : New BSD License(see VBMEG_LICENSE.txt) 0021 0022 load(bayesinitfile, 'Model'); 0023 0024 % [membershipmat] = make_membershipmat(proj_root, brainfile, parcelsfile); 0025 % note: this information is contained in Diffusion mri file(.dmri.mat) 0026 load(dmri_file, 'membershipmat'); 0027 0028 0029 Model.a = membershipmat(:,Model.ix)*Model.a; % Works only if patch_norm == OFF 0030 0031 % Initial values of current variance parameter 0032 a_init = max(Model.a*(bsnorm^2), a_min);