In MI cortex, a large bundle of labeled projections from SI coursed rostrally through cortical layer VI and abruptly turned toward the pial surface to form a vertical column of labeling (Figure 3C ). The labeled column was 400–500 ?m in width and extended upwards from upper layer VI to layer I. Inspection of the adjacent Nissl-stained section indicated that this labeling was located in the MI region that represents the transition from AGm to AGl. Collator note: seee Fig 3D, Swanson Atlas Levels 8-11 ( +3.00 - +1.50 mm from bregma).

[…] corresponding whisker representations were injected in both areas as indicated by the presence of BDA-labeled neurons at the FR injection site. Collator note: rostral double labeling of the Mop, rostrally. See Fig 5D, Swanson Atlas Levels 8-10 ( +3.10 - +2.20 mm from bregma). The amount of overlap is about 18-19% for SI and SII in layers III and V of the primary motor cortex (Fig. 7A).