function [conv, conv1] = convolution_type2 (conv1, tau_m, eps0, X)
% exponential decay
% input = conv1= convolution, decay component
% tau_m = decay time constant
% eps0= multiplying constant, scales the whole convolution
% X = spike train vector, if there is a spike the convolution jumps by 1
%output = conv = total convolution (scaled by eps0)
% conv1 = convolution, decay component (updated)
conv1 = conv1 + (-conv1)/tau_m + X;
conv = eps0.*(conv1);
end