Is it possible to decode which neuron represent which feature and why does it represent it?
Short answer: NO. 

Think about it, you could have 5 or 5000 neurons, and each neuron would represent a different thing in different models with different inputs. 

One of the problems of neural networks is that it is quite difficult to understand what is going inside them, they are a bit of a black box. Other techniques such as decision trees are much more easy to understand or explain to non-technical people.

The closest thing you could do is visualize the hidden layers and that might give you some sort of insight.