Sex-specific, postpuberty changes in mouse brain structures revealed by three-dimensional magnetic resonance...

Area of Science:

• Neuroscience
• Developmental Biology
• Comparative Anatomy

Background:

• Sexual dimorphism in brain structures is known in various species.
• The C57Bl/6(J) mouse is a widely used model for genetic brain function studies.
• Understanding sex-specific brain development is crucial for interpreting research findings.

Purpose of the Study:

• To investigate sex-dependent developmental changes in mouse brain structures.
• To characterize structural brain alterations from peripuberty to adulthood.
• To identify sexual dimorphisms in specific brain regions and ventricles.

Main Methods:

• High-resolution 3D magnetic resonance microscopy (MRM) was employed.
• Brains of adult and peripubertal male and female C57Bl/6(J) mice were imaged.
• Key brain structures (ventricles, hippocampus, amygdala, striatum) and total brain volume were reconstructed and analyzed.

Main Results:

• Both sexes showed overall brain growth from peripuberty to adulthood.
• The hippocampus and amygdala were disproportionately larger in adults compared to peripubertal mice, independent of brain size.
• Females had larger lateral ventricles and smaller amygdala (left side) than males.
• Lateral and third ventricles reduced in males only, indicating sex-specific developmental trajectories.
• Striatal size remained uniform across all groups.

Conclusions:

• Sex-specific brain transformations occur around puberty and continue into adulthood in mice.
• These findings reveal a more complex pattern of sexual dimorphism than previously recognized.
• The study provides valuable insights into the developmental neurobiology of sex differences.