Physiological and morphological properties of Dbx1‐derived respiratory neurons in the pre‐Bötzinger complex of neonatal mice

•  The transcription factor Dbx1 gives rise to putatively respiratory rhythm‐generating neurons in the pre‐Bötzinger complex. Comparative analysis of Dbx1‐derived (Dbx1+) and non‐Dbx1‐ derived (Dbx1−) neurons can help elucidate the cellular bases of respiratory rhythm generation. •  In vitro, Dbx1+ neurons activate earlier in the respiratory cycle, discharge larger magnitude inspiratory bursts and exhibit a lower rheobase compared with Dbx1− neurons. •  The Dbx1+ neurons tend to express the intrinsic currents IA (transient outward A‐current) and Ih (hyperpolarization‐activated current) in diametric opposition, which may facilitate temporal summation of excitatory synaptic inputs, whereas the Dbx1− neurons show no significant pattern of expression regarding IA and Ih. •  The Dbx1+ neurons exhibit smooth, spineless dendrites that project in the transverse plane, whereas the Dbx1− neurons are confined to the transverse plane to a lesser extent and sometimes exhibit spines. •  The properties of Dbx1+ neurons that may contribute to respiratory rhythmogenesis include a high level of excitability linked to ongoing network activity and dendritic properties that may facilitate synaptic integration.

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