Elsevier

NeuroImage

Volume 125, 15 January 2016, Pages 144-152
NeuroImage

Morphological maturation of the mouse brain: An in vivo MRI and histology investigation

https://doi.org/10.1016/j.neuroimage.2015.10.009Get rights and content
Under a Creative Commons license
open access

Highlights

  • Mouse brain volume is already stable at three weeks of age.

  • Mouse brain cortex continues to flatten till three months of age.

  • Myelination in mouse brain still increases till three months of age.

  • Mice need to be three months or older, when brain studies are to be done on adult animals.

Abstract

With the wide access to studies of selected gene expressions in transgenic animals, mice have become the dominant species as cerebral disease models. Many of these studies are performed on animals of not more than eight weeks, declared as adult animals. Based on the earlier reports that full brain maturation requires at least three months in rats, there is a clear need to discern the corresponding minimal animal age to provide an “adult brain” in mice in order to avoid modulation of disease progression/therapy studies by ongoing developmental changes. For this purpose, we have studied anatomical brain alterations of mice during their first six months of age. Using T2-weighted and diffusion-weighted MRI, structural and volume changes of the brain were identified and compared with histological analysis of myelination. Mouse brain volume was found to be almost stable already at three weeks, but cortex thickness kept decreasing continuously with maximal changes during the first three months. Myelination is still increasing between three and six months, although most dramatic changes are over by three months. While our results emphasize that mice should be at least three months old when adult animals are needed for brain studies, preferred choice of one particular metric for future investigation goals will result in somewhat varying age windows of stabilization.

Keywords

MRI
Mouse brain
Brain development
Cortex
Myelination
DTI

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