A comparative volumetric analysis of the prefrontal cortex in human and baboon MRI.
Level 5 - mechanism / opinion, no new human data
Comparative animal and human anatomical neuroimaging study (bench/animal research category).
PubMed 10559553 · doi:10.1159/000006620
What was done
Prefrontal cortex, dorsal prefrontal cortex, orbital prefrontal cortex, and total brain volumes were measured from magnetic resonance images in 20 healthy adult human females and 5 adult female baboons (*Papio anubis*).
What was found
The prefrontal cortex comprised a significantly larger proportion of total brain volume in humans than in baboons (12.51% vs 10.68%). Dorsal prefrontal volume accounted for 8.22% of total brain volume in humans versus 7.21% in baboons, and orbital prefrontal cortex accounted for 4.29% in humans versus 3.47% in baboons. Regression analysis indicated the human prefrontal cortex was larger than predicted for a baboon of equivalent total brain volume.
Why it matters
It demonstrates that while the human prefrontal cortex is proportionally larger than that of baboons, the magnitude of the relative volumetric difference is modest.
Limits
The sample size is very small, especially for baboons (n = 5). Only female subjects were examined, limiting generalizability across sexes. Gross volumetric MRI comparisons do not assess differences in cytoarchitecture, neuron density, or functional connectivity.
Cited by
- contradicts The prefrontal cortex constitutes 30% of the human brain by weight.