Laser ablation of Dbx1 neurons in the pre-Bötzinger complex stops inspiratory rhythm and impairs output in neonatal mice.
Bottom Line: To understand the neural origins of rhythmic behavior one must characterize the central pattern generator circuit and quantify the population size needed to sustain functionality.Breathing-related interneurons of the brainstem pre-Bötzinger complex (preBötC) that putatively comprise the core respiratory rhythm generator in mammals are derived from Dbx1-expressing precursors.These results demonstrate that a single canonical interneuron class generates respiratory rhythm and contributes in a premotor capacity, whereas these functions are normally attributed to discrete populations.
Affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, United States.Show MeSH
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Mentions: (A) Fluorescent image of a transverse slice from a Dbx1+/CreERT2; Rosa26tdTomato mouse pup. Anatomical landmarks are illustrated including: XII, the hypoglossal motor nucleus; scNA, semi-compact nucleus ambiguus; and IOP, the principal inferior olive. The domain for detection and ablation is indicated by the white boxes, bilaterally. Scale bar is 500 µm. (B) Mask of targets showing validated Dbx1 (red) and invalidated (blue) cells for all focal planes to a depth of −80 µm. Each image is 412 × 412 µm2 (as in Figure 1C). Image processing routines for detecting and validating Dbx1 neuron targets are detailed in ‘Materials and methods’, Figure 1—figure supplement 2, and a methodological paper (Wang et al., 2013). Note that the highest fraction of validated Dbx1 target cells is found at deeper focal planes, e.g., −80 µm due to the ‘priority rule’, which applies to overlapping ROIs in adjacent focal planes. According to the priority rule, the ROI from the deeper focal is accepted as a ‘bona fide’ target and the redundant ROI at the superficial level is rejected. Also see Figure 1—figure supplement 2C,D.
Affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, United States.