Correlation between Gyral Size, Brain Size, and Head Impact Risk across Mammalian Species

TL;DR

This study investigates the relationship between gyral size, brain size, and head impact risk across various mammalian species, suggesting that gyral size may influence vulnerability to head impacts and varies with lifestyle.

Contribution

It extends prior primate research by analyzing multiple species, revealing that gyral size is largely independent of brain size and correlates with head impact risk and lifestyle.

Findings

Gyral size is largely independent of brain size across species.

Species with headbutting behaviors have smaller gyral sizes.

Lissencephalic brains are associated with lower head impact risk.

Abstract

A study on primates has established that gyral size is largely independent of overall brain size. Building on this, and other research suggesting that brain gyrification may mitigate the effects of head impacts, our study aims to explore potential correlations between gyral size and the risk of head impact across a diverse range of mammalian species. Our findings corroborate the idea that gyral sizes are largely independent of brain sizes, especially among species with larger brains, thus extending this observation beyond primates. Preliminary evidence also suggests a correlation between an animal's gyral size and its lifestyle, particularly in terms of head-impact risk. For instance, goats, known for their headbutting behaviors, exhibit smaller gyral sizes. In contrast, species such as manatees and dugongs, which typically face lower risks of head impact, have lissencephalic brains. Additionally, we explore mechanisms that may explain how narrower gyral sizes could offer protective advantages against head impact. Finally, we discuss a possible trade-off associated with gyrencephaly.