Figure 3. Subnucleus interpolaris from a postnatal day 5 C57 mouse processed for cytochrome oxidase to reveal the barrelettes.

The whiskers have an inverted representation with the 5 rows of large whiskers represented ventrally whereas the chin is represented dorsally in a separate module. A small cleft in the barrelette pattern (N) is congruent with the position of the nose on the mouse's face. The designations for chin (filled arrowhead) nose (filled arrow) and dorsal whiskers (open arrow) are used to designate the same parts of the water shrew whisker pad and SpVi barrelettes (Figure 4).