(red) and DAPI (blue) to show nuclei.
Epifluorescence. Sometimes called the
olfactory cortex,
olfactory lobe or
paleopallium, piriform cortical regions are present in the brains of
amphibians,
reptiles and
mammals. The piriform cortex is among three areas that emerge in the
telencephalon of amphibians, situated
caudally to a dorsal area, which is caudal to a hippocampal area. Further along the
phylogenic timeline, the telencephalic bulb of reptiles as viewed in a cross section of the transverse plane extends with the
archipallial hippocampus folding toward the midline and down as the dorsal area begins to form a recognizable cortex. As mammalian brains developed, volume of the dorsal cortex increased in slightly greater proportion, as compared proportionally with increased overall brain volume, until it enveloped the
hippocampal regions. Recognized as
neopallium or
neocortex, enlarged dorsal areas envelop the
paleopallial piriform cortex in
humans and
Old World monkeys. Among
taxonomic groupings of mammals, the piriform cortex and the
olfactory bulb become proportionally smaller in the brains of
phylogenically younger species. The piriform cortex occupies a greater proportion of the overall brain and of the telencephalic brains of
insectivores than in
primates. The piriform cortex continues to occupy a consistent albeit small and declining proportion of the increasingly large
telencephalon in the most recent primate species while the volume of the olfactory bulb becomes less in proportion. ==See also==