Parabrachial tachykinin1-expressing neurons involved in state-dependent breathing control

Breathing is regulated automatically by neural circuits in the medulla to maintain homeostasis, but breathing is also modified by behavior and emotion. Mice have rapid breathing patterns that are unique to the awake state and distinct from those driven by automatic reflexes. Activation of medullary neurons that control automatic breathing does not reproduce these rapid breathing patterns. By manipulating transcriptionally defined neurons in the parabrachial nucleus, we identify a subset of neurons that express the Tac1, but not Calca, gene that exerts potent and precise conditional control of breathing in the awake, but not anesthetized, state via projections to the ventral intermediate reticular zone of the medulla. Activating these neurons drives breathing to frequencies that match the physiological maximum through mechanisms that differ from those that underlie the automatic control of breathing. We postulate that this circuit is important for the integration of breathing with state-dependent behaviors and emotions. Breathing is controlled automatically but is also conditionally integrated with behavior and emotion in awake animals. Here, authors identify brainstem neurons that are important for controlling awake-state-dependent breathing patterns in mice.

Automated summary

Breathing is regulated automatically by neural circuits in the medulla, but it is also influenced by behavior and emotion. Researchers identified a subset of neurons in the parabrachial nucleus that control specific breathing patterns in awake mice. These neurons exert conditional control over breathing in the awake state through projections to the ventral intermediate reticular zone of the medulla.