The exact location and functionality of the cough center has remained somewhat elusive: while Johannes Peter Müller observed in 1838 that the medulla coordinates the cough reflex, investigating it has been slow because the usual anaesthetics for experimental animals were morphine or opiates, drugs which strongly inhibit cough. In addition, the center likely overlaps with the respiratory rhythm generator networks. It is hence not so much a specific area, but a function within the respiration and reflex networks of the brainstem.
Cough receptors project to relay neurones in the solitary nucleus, which project to other parts of the respiratory networks. In particular, the pre-Bötzinger complex may act as a pattern generator for the cough response. Parts of the caudal medullary raphe nucleus (nucleus raphe obscurus and nucleus raphe magnus) are known to be essential for the cough response. Other systems that may be involved in pattern generation and regulation are the pontine respiratory group, the lateral tegmental field and the deep cerebellar nuclei. Successful joint models of medullary systems coordinating breathing, coughing and swallowing has been constructed based on this model.
Coughing can occur or be inhibited as a voluntary action, suggesting control from higher systems in the brain. Functional brain imaging of voluntary, suppressed, and induced coughing show that a number of cortical areas can get involved and may be important even for non-voluntary coughing. In contrast, voluntary coughing does not seem to activate medullary systems.
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