All behaviors require coordinated activation of motoneurons from central command and premotor networks. The genetic identities of premotoneurons providing behaviorally relevant excitation to any pool of mammalian motoneurons remain unknown. Recently we established in vitro that Dbx1-derived preBötzinger complex neurons are critical for rhythm generation and that a subpopulation serves a premotor function (Wang et al., 2014). Here we further show that a subpopulation of Dbx1-derived intermediate reticular (IRt) neurons are rhythmically active during inspiration and project to the hypoglossal (XII) nucleus that contains motoneurons important for maintaining airway patency. Laser ablation of Dbx1 IRt neurons, 57% of which are glutamatergic, decreased ipsilateral inspiratory motor output without affecting frequency. We conclude that a subset of Dbx1 IRt neurons is a source of premotor excitatory drive, contributing to the inspiratory behavior of XII motoneurons, as well as a key component of the airway control network whose dysfunction contributes to sleep apnea.
Animal experimentation: Ethics Statement: All experiments were performed in accordance with guidelines laid down by the NIH in the US regarding the care and use of animals for experimental procedures, the Institute for Laboratory Animal Research, and in compliance with protocols approved by the College of William & Mary Institutional Animal Care and Use Committee (protocol #8828), the Animal Studies Committee at Washington University School of Medicine (protocol #20110249) and the University of Alberta of Medicine Animal Welfare Committee (protocol #255).
- Ole Kiehn, Karolinska Institutet, Sweden
© 2015, Revill et al.
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