There have been projects to systematically catalog all the synapses in the flatworm. The problem is that neural plasticity means these connections change dynami

There have been projects to systematically catalog all the synapses in the flatworm. The problem is that neural plasticity means these connections change dynamically over time based on the needs of the organism. Since the only way we can study the flatworm at the synapse level is by killing the worm and mounting it on slides and staining it and viewing it through a high power microscope, we can only analyze its structure at points frozen in time (and formaldehyde). The reason we will never be able to truly model and understand neural networks (irl) is because their plasticity is very difficult to study with our current methods. Not only do the quantity and location of the synapses change, but the concentration and type of neurotransmitters at the synapses change. And on top of that the concentration of the neurotransmitter receptors are constantly being up regulated and down regulated by the receiving neuron. Each of these factors is really important to what the neuron is actually doing. This is why even a simple organism can have basically an unlimited amount of complexity. To understand a dynamic system like this would require very precise measurements of very small particles in vivo which is currently impossible with our tools.