RtST boutons that form reticulo-propriospinal contacts contain synaptophysin (a). RtST collateral (green), PrIN cell body (red), and synaptophysin (blue). An orthogonal z-view of the x-axis is shown on the right hand side, and an orthogonal z-view of the y-axis is shown in the bottom. The thin yellow lines indicate the location of the orthogonal views. (b) High-magnification image of RtST bouton, forming a contact with PrIN cell body process. Individual channels are displayed diagonally, down, and to the right. Orthogonal z-views of the y-axis are shown on the right side and orthogonal z-views of the x-axis are shown in the bottom. Orthogonal views demonstrate colabeling of the bouton, process, and synaptophysin on the same focal plane. The site of contact is indicated by the arrowhead on the x-axis, and synaptophysin immunoreactivity within the RtST bouton is indicated by the arrow on the y-axis. Scale bar = 20 μm (a). Scale bar = 5 μm (b).