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: spm_dem_ERP.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/toolbox/DEM
    
    the code of the file until where you have to start completion: function [R] = spm_dem_ERP(varargin)

    
function [R] = spm_dem_ERP(varargin)
% simulated electrophysiological response based on conditional estimates
% FORMAT [R] = spm_dem_ERP(qU,qU,...)
% qU - conditional estimates of states
% R  - summed response over peri-stimulus time
%
% These simulated response assume that LFPs are generated by superficial
% pyramidal cells that correspond to units encoding prediction error.
% Peristimulus time histograms (PSTH) assume that states (U) are encoded
% using a non-negative firing rate that is proportional to exp(U), using
% an opponent system
%__________________________________________________________________________


% loop over ERPs
%--------------------------------------------------------------------------
clf
N     = length(varargin);
color = {'r','b','g','y','c','m'};
for i = 1:N
    
    
    % loop over ERPs
    %----------------------------------------------------------------------
    qU = varargin{i};
    n  = length(qU.z);
    for  j = 1:n
        
        % PST (assuming 8ms times bins)
        %------------------------------------------------------------------
        try
            EEG = qU.Z{j};
        catch
            EEG = qU.z{j};
        end