If you don't mind, could you share some resources on existing models that approximate the neuron behaviour more accurately? If you're talking about feedback-driven models like RNNs/LSTMs/GRUs/etc, then I can safely say that there are people working on realising these models on custom computing architectures. The simple feed-forward neural network could be thought of as the low-hanging fruit in this regard, which, nevertheless, is still an impressive feat.