Normative brain size variation and brain shape diversity in humans.

Area of Science:

• Neuroscience
• Human Evolution
• Brain Development

Background:

• Brain size varies significantly in humans, impacting organization.
• Understanding how individual brain size variation affects brain structure is crucial.

Purpose of the Study:

• To investigate the relationship between brain size and brain organization in humans.
• To explore how brain size variation impacts cortical network expansion.

Main Methods:

• Utilized in vivo neuroimaging data from over 3000 typically developing individuals.
• Analyzed areal expansion across different brain regions and networks.

Main Results:

• Larger human brains exhibit greater areal expansion in frontoparietal cortical networks and associated subcortical regions.
• This expansion is disproportionately greater compared to limbic, sensory, and motor systems.
• The observed areal redistribution mirrors evolutionary cortical remodeling and is present from early childhood.

Conclusions:

• Human brain shape is systematically linked to natural variations in brain size.
• A specific scaling map integrates evolutionary and developmental neurobiology.
• This coupling is associated with increased metabolic cost and neuronal connectivity in larger brains.