The young adult human brain: an MRI-based morphometric analysis

Area of Science:

• Neuroimaging
• Human Anatomy
• Radiology

Background:

• Establishing normative volumetric data for the young adult brain is crucial for clinical and research applications.
• Understanding sex-based differences (sexual dimorphism) in brain structure is essential for interpreting neurological conditions.

Purpose of the Study:

• To characterize in vivo brain and substructure volumes using 3D MRI.
• To assess volumetric symmetry in bilateral brain structures.
• To investigate sex-based volumetric differences in the young adult brain.
• To create a normal volumetric database for young adult brains.

Main Methods:

• Three-dimensional magnetic resonance imaging (MRI) scans were acquired from 10 male and 10 female young adults.
• Morphometric analysis was performed to quantify whole brain and substructure volumes.
• Discriminant analysis was used to assess the predictive power of volumetric measures for gender.

Main Results:

• Total brain volumes ranged from 1173 to 1626 cm³.
• Most bilateral structures exhibited symmetry, with minor exceptions (e.g., right neocortex, right amygdala, left lateral ventricle).
• Male brains were significantly larger in cerebellar volume compared to females; cerebral hemisphere volume did not differ significantly.
• Females had less cerebral white matter but larger caudate volumes; proportions of caudate and hippocampus relative to total cerebral volume were greater in females.
• Volumetric measures accurately predicted gender in 85% of subjects.

Conclusions:

• The study provides a foundational database for young adult brain morphometry.
• Unexpected findings regarding brain symmetry and sexual dimorphism were observed.
• Morphometric parameters, particularly caudate and hippocampal proportions, show potential for gender prediction.