Fig. 4.

Computational analysis of cortical odor representations. Shown is a hierarchical cluster analysis of c-Fos labeling patterns. Cortical patterns are grouped according to similarity (average linkage). Pattern similarity is expressed as cluster distance. The 42 cortices analyzed form four large groups. Patterns elicited by the same odorant in different individuals and the two hemispheres are almost invariably in the same group. Odorants are as follows: And, androstenone; Amy, amyl cinnamic aldehyde; Ben, benzyl mercaptan; Cam, camphor; Con, coniferan; Dim, dimethylpyrazine; Eth, ethyl butyrate; Fru, fructone; Men, menthol; MeA, methylamine; MeB, methyl butane thiol; Ora, orange flower ether; Pen, pentadecalactone; and Van, vanillin. Different mice exposed to the same odorant are indicated by numbers. L, left hemisphere; R, right hemisphere.