Fig. 2: Mafa⁺ neurons of the reticular formation in the caudal medulla are inhibitory.

a Whole mount (ventral view) of a Mafa ^LacZ/+ brain at E15 showing Mafa expression (Xgal staining, dark blue) restricted to the olfactory bulb (OB), to the pre-optic area of the hypothalamus (POA) to the brainstem (pons and medulla) and to the spinal cord. b Hemi-transverse section (medial left, dorsal top) of a Mafa^LacZ/+ pup at P0 showing that the preBötC area, below ChAT⁺ neurons (white) of the nucleus ambiguous (nAmb), is devoid of gal+ cells (red). c Same as b showing the absence of bgal+ cells (red) in the RTN, below ChAT+ neurons (white) of the facial motor nucleus (Mo7). d Transverse section of a Mafa^LacZ/+ pup at P0 (at the d axial position indicated in a) showing Mafa⁺ cells immunostained for bgal (black) in the caudal medulla in the spinal part of the trigeminal nucleus (sp5), in the peri12 reticular formation laterally to the hypoglossal motor nucleus (Mo12), in motoneurons of the accessory hypoglossal motor nucleus (acc-Mo12). e Close-up view of Mafa⁺ peri12 neurons (red) counterstained for ChAT⁺ (black) motoneurons at the same axial level as d. Transverse section (at the f axial position indicated in a) showing Mafa⁺ cells in the Sp5 and medial to the nucleus ambiguus in the peri-nAmb area. g Close up view of a hemi-transverse section (medial left, dorsal top) showing Mafa⁺ cells (red labeling) combined to Gad1 in situ hybridization (black) at the same axial level as (f) showing Gad1⁺/Mafa⁺ cells in the peri12 and peri-nAmb. Close-up view from the (h) inset in (g). Close-up view from the i inset in (g). j Quantification of neurochemical types of Mafa⁺ neurons of the caudal medulla reticular formation by in situ hybridization for VGlut2 (13 section counts), Glyt2 (11 section counts), Gad1 (10 section counts) and Gad2 (12 section counts). Note that Mafa⁺ neurons of the caudal reticular formation (peri12 and peri-nAmb regions) are predominantly inhibitory. Plots represent mean ± sem. Scale bars (μm): 100 (b–g), 20 (h, i).