Location: BG_SOC @ 28e64c6cee18 / parameter_finder / find_G_GHK.m

Author:

Shelley Fong <sfon036@UoA.auckland.ac.nz>

Date:

2025-07-03 11:06:11+12:00

Desc:

Adding BG diagram

Permanent Source URI:

https://staging.physiomeproject.org/workspace/d41/rawfile/28e64c6cee18d3c7b7f6cba44fd400ca290b91e9/parameter_finder/find_G_GHK.m

% adapted from Pan

clear;
% clc;
close all;

%% Options
run_optimisation = true;

%% Set up directories
current_dir = cd;
Idx_backslash = find(current_dir == filesep);
main_dir = current_dir;%(1:Idx_backslash(end));
data_dir = [main_dir '\data' filesep];
output_dir = [main_dir '\output' filesep];
storage_dir = [main_dir '\storage' filesep];

%% Define constants
R = 8.314;
T = 310;
F = 96485;

%% Plot I-V curves
cCao_st = 1.8;
cCao = 1.8;
cCai_st = 0.12e-3;
cCa_SR = 1.8;

g_kinetic = 0.1; % nS
% Original
G_SOC = g_kinetic*1e-6; % Unit mA/V = mS

V = (-120:1:60)/1000;
E_Ca = R*T/F*log(cCao/cCai_st);
I_lin = G_SOC*(V-E_Ca); % Unit mA
fit_range = 10:round(length(I_lin)*0.75); % 31:91
error_func = @(G_GHK) square_error(I_lin(fit_range) - calc_IGHK(G_GHK,V(fit_range),cCai_st,cCao));

A = [];
b = [];
Aeq = [];
beq = [];
lb = [-Inf];
ub = [Inf];

options_ps = optimoptions('particleswarm','UseParallel',true,'HybridFcn',@fminunc,'SwarmSize',2000);

if run_optimisation
    [G_GHK,fval,exitflag,output] = particleswarm(error_func,1,lb,ub,options_ps);
    save([storage_dir 'SOC_G_GHK.mat'],'G_GHK');
else
    load([storage_dir 'SOC_G_GHK.mat']);
end
I_GHK = calc_IGHK(G_GHK,V,cCai_st,cCao);

h = figure;
plot(1000*V,1e6*I_lin,'k--',1000*V,1e6*I_GHK,'k','LineWidth',2);
legend('LRd','BG','Location','southeast');
ylabel('Current (nA)');
xlabel('Voltage (mV)');
set(gca,'FontSize',16);

% print_figure(h,output_dir,'SOC_IV_curve');