The neuromodulatory response: Integrating second messenger pathways

The three themes of this chapter develop upon the nature of the neuromodulatory response. First, the neuromodulatory response is shaped by multiple second messenger pathways acting within positive and negative feedback loops. Second, second messenger pathways are interwoven, and it is their interactions that complete the feedback loops of the response. Third, the evolution of the neuromodulatory response in a special command system for a fixed action pattern of behavior is considered by comparative analysis and found to be elaborated simply from second messenger and ion conductance properties shared by many neurons.