How much does the SPAUN and the Semantic Pointer Architecture (SPA) that was used to build it take neurotransmitters into account? In the book How to Build a Brain, various inhibitory and excitatory connections are mentioned as supplying a biological foundation for implementing the Basal Ganglia. Additionally, it's mentioned that the learning rule that the SPA uses, hPES, uses dopamine to modulate learning. However, I'm still a bit confused on the details of all this. How do neurotransmitters fit into Nengo? How much detail does Nengo go into in regards to neurotransmitters? Does it take into account the neurotransmitter distribution and consumption as observed in the brain?
Note: For more information on the relation between Nengo, SPA and SPAUN, please see my previous question.