Extended Data Fig. 5: Characteristics of the midbrain projecting types 16–31.
From: Projectome-based characterization of hypothalamic peptidergic neurons in male mice
a. A dot plot depicting selective projections of each type (row) in each brain area (column). The dot circle’s size and color intensity indicate the percentage of neurons in each type that project to the indicated brain area and the average projection length (in μm) in a heatmap fashion, respectively, with the scale on the right. b–i. The total axon projections of neurons of the indicated type are plotted in a 3D brain on the left. Zoom-in views of representative axon projections from three representative neurons (color-coded) from each type in defined subdomains of the indicated target areas are shown on the right. Scale bar, 500 μm. j. Schematics showing the nuclei and column structures of the PAG, which includes anterior PAG (aPAG) and rostral nuclei (INC, Su3, ND, and PRC), as well as four longitudinally organized PAG columns - dorsomedial (dm), dorsolateral (dl), lateral (l), and ventrolateral (vl) PAG. k. A dot plot depicting selective projections of each type (row) in each PAG column/nucleus on the ipsilateral or contralateral side. The dot circle’s size and color intensity indicate the percentage of neurons in each type that project to the indicated brain area and the average projection length (in μm) in each column/nucleus in a heatmap fashion with the scale shown on the right. l. Zoom-in views of representative axon projections of three neurons (color-coded) from the indicated type in a coronal (top) and sagittal (bottom) plane of a PAG section. Scale bar, 500 μm. Dashed lines show the position of the coronal section on the sagittal plane. m. Correlation (corr) analysis of preference index in the ipsilateral (ipsi) and contralateral side (contra) of the indicated PAG column/nucleus for bilaterally PAG-projecting neurons. Representative images on the bottom show a coordinated innervation pattern of a similar column/nucleus in both hemispheres by two bilaterally PAG-projecting neurons. n. Heatmap representation (sorted) of column/nucleus preference score for projections in the ipsilateral PAG, calculated as the fold difference of projection density (total arbor length divided by the volume of targeted area) for a particular column/nucleus relative to the average projection density for all areas, of individual neurons in each type.
