Do mouse sex differences in brain volume match humans?
Human males have larger/more variable total brain volume (mice do not); after TTV control, sex-effect sizes across 60 homologous regions correlate modestly (r=0.30), higher in cortex, tracking congruence of 2835 homologous genes.
Source
Comparative neuroimaging of sex differences in human and mouse brain anatomy
Study at a glance
- Design
- Cross-sectional — Comparative structural MRI of sex differences in human and mouse brains plus regional gene-expression congruence
- N
- N=1522 · Humans 597F/496M; mice 213F/216M (TTV analysis)
- Population
- Healthy young adult humans and mice with homologous regional atlases
- Outcome
- Cross-species congruence of volumetric sex effects and linked gene-expression profiles
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Do mouse sex differences in brain volume match humans?
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Human sample 597F/496M; mouse 213F/216M for TTV.
Results Males have larger brains than females in humans but not in mice We first examined the effects of sex on total tissue volume (TTV) in humans (597 females/496 males) and mice (213 females/216 males) using structural MRI data from healthy young adults in both species.
Cross-species volumetric sex-effect congruence r=0.30 across 60 regions.
After controlling for total brain volume, we observe modest cross-species congruence in the volumetric effect size of sex across 60 homologous regions ( r =0.30).
What they did
Used structural MRI to compare sex differences in total and regional volumes between humans and mice, then related regional volumetric sex-effect congruence to cross-species gene-expression profiles.
What they found
Humans: males ~13.5% larger TTV; mice: no significant TTV sex difference. After TTV correction, ~65.8% of human and ~58.6% of mouse regions showed sex differences. Cross-species volumetric sex-effect congruence r=0.30 overall (cortex r=0.33; non-cortex r=0.16), aligning with expression congruence of 2835 homologous genes especially in primary sensory cortex.
The limits
What it doesn't show
Congruence is correlational and atlas-dependent; it does not prove shared developmental mechanisms for every homologous region.
Key terms
- Total tissue volume (TTV)
- Whole-brain volume measure compared between sexes/species.
- Homologous regions
- Corresponding brain areas mapped across human and mouse atlases.
- Effect-size congruence
- Correlation of regional sex-effect magnitudes across species.
- Structural MRI
- Imaging modality used to measure regional volumes.
- Gene-expression profile
- Regional expression of homologous genes linked to volumetric congruence.
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Quiz yourself
Human male TTV vs female:
Common questions
Human TTV sex difference?
~13.5% larger in males.
Mice TTV sex difference?
Not statistically significant (~0.3%).
Overall regional congruence r?
0.30 across 60 homologous regions.
Genes in expression analysis?
2835 homologous genes.