Supplementary Figure 4: Virus was well-restricted to MEC, with little spread to LEC.

Histological analysis of 4 hemispheres revealed only minor leakage of virus into the LEC (5.0 ± 3.5% of LEC). Images of DAPI and GFP were taken separately and then combined in Photoshop. The intensities of the blue and green channels were adjusted separately to allow for clear visualization of the GFP expression. (a) Sagittal brain sections showing virus expression across the medial–lateral axis (left to right: lateral to medial). Images of Cre-GFP (green) are overlaid on images of DAPI (blue). The white dotted lines depict the dorsal MEC border (top), the MEC–LEC border (middle), and the ventral LEC border (bottom). Each row shows slices from a different mouse (n = 3). (b) Horizontal brain sections from an individual mouse showing virus expression. Dorsal to ventral sections are shown from left to right. The white dotted lines depict the anterior LEC border (left), MEC-LEC border (middle), and MEC-parasubiculum border (right). Scale bars: 1 mm.