Abstract
Given their importance in language comprehension, the human temporal lobes and/or some of their component structures might be expected to be larger than allometric predictions for a nonhuman anthropoid brain of human size. Whole brain, T1-weighted MRI scans were collected from 44 living anthropoid primates spanning 11 species. Easyvision software (Philips Medical Systems, The Netherlands) was used to measure the volume of the entire brain, the temporal lobes, the superior temporal gyri, and the temporal lobe white matter. The surface areas of both the entire temporal lobe and the superior temporal gyrus were also measured, as was temporal cortical gyrification. Allometric regressions of temporal lobe structures on brain volume consistently showed apes and monkeys to scale along different trajectories, with the monkeys typically lying at a higher elevation than the apes. Within the temporal lobe, overall volume, surface area, and white matter volume were significantly larger in humans than predicted by the ape regression lines. The largest departure from allometry in humans was for the temporal lobe white matter volume which, in addition to being significantly larger than predicted for brain size, was also significantly larger than predicted for temporal lobe volume. Among the nonhuman primate sample, Cebus have small temporal lobes for their brain size, and Macaca and Papio have large superior temporal gyri for their brain size. The observed departures from allometry might reflect neurobiological adaptations supporting species-specific communication in both humans and old world monkeys.
Original language | English (US) |
---|---|
Pages (from-to) | 505-533 |
Number of pages | 29 |
Journal | Journal of Human Evolution |
Volume | 42 |
Issue number | 5 |
DOIs | |
State | Published - 2002 |
Funding
This project was supported by grants to JKR from the Leakey Foundation and the Markey Foundation for Neurological Sciences, as well as the Yerkes Center base grant NIH RR-00165. We thank Tom Insel for his support and guidance in collecting and analyzing these data and we thank Melvin Konner for invaluable input and advice.
Keywords
- Allometry
- Brain
- Comparative study
- Evolution
- MRI
- Primates
- Temporal lobe
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Anthropology