(A) Summary of time course of the IPSC decay for the GABAergic component for different regions of the IO (from Turecek and Regehr, 2019). Abbreviations are defined in Figure 7. (B) Low-magnification of coronal sections of the IO immunolabeled for Vgat (green, left) to mark GABAergic and glycinergic inputs in a GlyT2Cre; R26LSL-synaptophysin-TdT (Ai34) mouse, Synaptophysin TdT labeled glycinergic boutons (cyan, middle), and immunostaining labeled Syt1/2 (magenta, right). Images are of the rostral (top) and caudal (bottom) IO. Scale bar is 200 µm. (C) High-magnification single plane images of inhibitory boutons from each subnucleus of the IO and the surrounding reticular formation (RF). From top to bottom: Vgat (green), Synaptophysin TdT in glycinergic boutons (cyan), Syt1/2 (purple), and a combined image of Vgat and Syt1/2. The lower three panels show analysis of each identified bouton. Boutons are color-coded for the degree of signal correlation of Vgat and Syt1/2 (R2). Boutons are separated into Vgat-positive (top), glycinergic boutons (GlyT2+, middle), and non-glycinergic Vgat-positive boutons (GlyT2-, bottom). Scale bar is 1 µm. (D) Distribution of R2 for all boutons in identified regions of the IO for glycinergic (top) and GABAergic synapses (bottom). (E) Signal correlation (R2) of Vgat and Syt1/2 for all identified Vgat-positive boutons (left), for glycinergic boutons expressing TdT and Vgat (middle), and for exclusively GABAergic synapses expressing Vgat but not TdT (right).