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. 2021 Nov 10;237:102903. doi: 10.1016/j.autneu.2021.102903

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© 2021 The Authors

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Fig. 2 — Autonomic nervous system and immune system: central and peripheral communication (more details in Fig. 3).

Positive feedback loops exist between AND within the central and peripheral communication. Example: Elements of peripheral communication sensitize each other: Thus, immune cells AND nerve fibers produce cytokines and substance P (SP), which in turn induce the immune cells and nerve fibers to produce even more cytokines and SP (positive feedback loop). The brain is then informed of the cytokine and SP concentration; it knows via the afferent nerve fibers the site of tissue damage and the incipient inflammation. Now, this information is processed (central communication) and the resulting output is then communicated to the periphery by means of the efferents shown here (communication between center and periphery).