You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: getPriors.m
    path of file: ./repos/PsPM/src/ext/VBA/subfunctions
    
    the code of the file until where you have to start completion: function [priors] = getPriors(nreg,n_t,options,reduced_f,stochastic)
% builds priors for DCM inversion
% function [priors] = getPriors(nreg,n_t,options,reduced_f,stochastic)
% IN:
%   - nreg: # regions in the network
%   - n_t: length of the time series
%   - options: options structure, containing at least the .inF and .inG
%   fields, as built using prepare_fullDCM.m
%   - reduced_f: a flag for fixing a subpart of the hemodynamic parameters
%   (oxygen extraction fraction at rest, vasodilatory signal feedback rate
%   and vessel stifness) to their prior value

    
function [priors] = getPriors(nreg,n_t,options,reduced_f,stochastic)
% builds priors for DCM inversion
% function [priors] = getPriors(nreg,n_t,options,reduced_f,stochastic)
% IN:
%   - nreg: # regions in the network
%   - n_t: length of the time series
%   - options: options structure, containing at least the .inF and .inG
%   fields, as built using prepare_fullDCM.m
%   - reduced_f: a flag for fixing a subpart of the hemodynamic parameters
%   (oxygen extraction fraction at rest, vasodilatory signal feedback rate
%   and vessel stifness) to their prior value
%   - stochastic: a flag for stochastic DCM
% OUT:
%   - priors: the 'priors' structure that can be used to invert the DCM
%   using VBA_NLStateSpaceModel.m

extend