Brief communication: how much larger is the relative volume of area 10 of the prefrontal cortex in humans?
Level 5 - mechanism / opinion, no new human data
Secondary re-analysis and theoretical commentary on published comparative primate datasets (level assigned by non-clinical design analogy).
PubMed 12124920 · doi:10.1002/ajpa.10090
What was done
The author performed an allometric re-analysis of published comparative neuroanatomical datasets (Semendeferi et al., 2001; Stephan et al., 1981) to calculate the relative volume increase of Brodmann's area 10 in the human prefrontal cortex compared to non-human hominoid brains based on allometric scaling with total brain weight.
What was found
The relative increase in human prefrontal area 10 volume was calculated to be 6% larger than predicted by allometric scaling. The abstract notes that this 6% residual value indicates human frontal lobe and prefrontal cortex volume conforms to expected primate brain-size allometry, contradicting claims of a ~200% relative expansion.
Why it matters
It challenges widespread claims of massive, disproportionate prefrontal cortex expansion in humans, demonstrating that human prefrontal volume largely reflects expected scaling for a primate of human brain size.
Limits
The paper is a brief communication based entirely on secondary calculations of previously published data rather than new primary anatomical measurements. Sample sizes, species counts, variance metrics, and confidence intervals are not reported in the abstract.
Cited by
- contradicts The relative size of the human prefrontal cortex is uniquely large compared to close animal relatives.