Neurons "reuse"
There is an inportant subtlety when on is trying to interpret what a Neural Network actually does – each neuron, it seems, gets activated on a different set of inputs which corresponds to very different set of features. It is most prominent in a computer vision settings, when a selected neuron reacts on completely unrelated parts of inputs, say of cats and of cars. Let’s see what is going on out there. The problem comes from the fact that the same “early” layers of neurons has been given completely unrelated sets of inputs. In other words, there is no specialization yet. On the other hand, the “wiring” of the visual system is deliberate and specialized, which is opposite of a “fully connected” networks. ...