Can we even understand what the responses of a neuron ‘represent’?

tl;dr: - Deep neural networks are forcing us to rethink what it means to understand what a neuron is doing - Does it make sense to talk about a neuron representing a single feature instead of a confluence of features (a la Kording)? Is understanding the way a neuron responds in one context good enough? - If a neural response is correlated with something in the environment, does it represent it? - There is a difference in understanding encoding versus decoding versus mechanistic computations -...