Artificial Neural Network Classifier in Matlab
I'm not a code reviewer, but I'd like to comment on the design of your network, which you certainly seem to be doing just fine.


It might be rather difficult to make any judgment, given that the application is undefined, while it seems you are designing a neural-network based detector. 
Numerically speaking, you might focus on your validation performance, by constantly redesigning your network architecture (e.g., number of hidden layers, number of hidden neurons, reducing and increasing batch sizes, training functions/methods as you mentioned, etc.), input preprocessing (e.g., smoothing, input interpolation or extrapolation in case possible, artifact removal, etc.). 
Not knowing what your datasets might be and how sophisticated that may be, you may focus on 10^-3 to 10^-6 convergence range. It might increase the performance (e.g., confusion matrices) of your network.


Overall, it seems your input is pretty stochastic. Input preprocessing may be worth looking into.