Figure 3. Word frequencies across species. A, Hinton plots for anatomic, neurochemical, and disease-related terms in papers focused on the prefrontal cortex of mice, rats, monkeys, and humans. In each plot, columns denote species and rows denote terms. The relative frequency of each term is represented by a square, and the size of the square is defined as the word count divided by total words. Plots are color coded using the same colors as in Figure 2. Most notable, was the use of certain anatomic terms in monkey studies (e.g., FEF, OFC, vlPFC) that are not common in the human or rodent literature. B, Bar plots of the most common terms for rodents (mice and rats) and primates (monkeys and humans). Anatomic terms were sharply divided across orders (rodents versus primates). Rodent studies were focused on the “mPFC,” and primate studies were focused on the “dlPFC.” By contrast, publications focused on neurotransmitters such as dopamine and serotonin were more common in rodent studies, but the relative frequencies of these terms were not discordant across species. A somewhat different finding was apparent in relative word frequencies for diseases and disorders. Rodent studies, especially in rats, more often addressed stress than studies in primates, and primate studies more often addressed schizophrenia compared to the rodent literature.