Figure 1.

Injection sites and resultant retrograde labeling. A, B, Examples of injection sites limited to the ventral posterior or posterior medial nucleus. The dashed line indicates the border between these two nuclei. C, Retrograde labeling of primary somatosensory cortex after injection into the ventral posterior nucleus. The layers are indicated and were determined from staining with bisbenzamide and viewed through the appropriate filter (image not shown). Furthermore, alternate sections were stained with cytochrome oxidase to demonstrate the location of barrel and nonbarrel cortex as in F and G. D, E, Retrograde labeling of primary somatosensory cortex after injection into the posterior medial nucleus. The layers are indicated and were determined as in C. F, G, Alternate sections showing cytochrome oxidase staining (F) and retrograde labeling (G). The arrows in F indicate barrels and are repeated in G.