Male prevalent enhancement of leftward asymmetric development of the cerebellar cortex in ferrets (Mustela putorius)

Abstract

The present study was conducted in MRI-based volumetry to characterize the sexual dimorphism of the cerebellum in young adult ferrets. High spatial resolution 3D anatomical MRI at 7-tesla were acquired ex vivo from fixed cerebella of 90-day-old male and female ferrets. The 3D morphology and topology of cerebellar structures were reproduced well by volume-rendered images obtained from MRI. Volume of the whole cerebellum was significantly larger in males than in females. The cerebellar cortex was further divided into five transverse domains: the anterior zone (AZ; lobules I-V), central zone anterior (lobule VI), central zone posterior (CZp; lobule VII), posterior zone (PZ; lobules VIII-IXa) and nodular zone (NZ; lobules IXb -X). Significantly greater volumes in males than in females were detected bilaterally in the AZ, CZp, and NZ, and leftward in PZ. Notably, the significant volume asymmetry was detected leftward in the CZp of males. By asymmetry quotient analysis, the counterclockwise torque asymmetry of the cerebellum was revealed, and it was more striking in males than in females. The present results suggest that sexual dimorphism of the ferret cerebellum is characterized by enhancing the leftward laterality in the CZp in males, forming the distinctive counterclockwise torque asymmetry.

Keywords:

• Cerebellum
• Sex difference
• Carnivore
• MRI
• Volumetry.

The authors wish to thank Mr. Nobuhiro Nitta (Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan) for MRI measurements.No potential conflict of interest was reported by the authors.This study was supported by JSPS KAKENHI (23590223), and partly supported by “the Center of Innovation Program from Japan Science and Technology Agency, JST” for MRI study.

The authors wish to thank Mr. Nobuhiro Nitta (Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan) for MRI measurements.No potential conflict of interest was reported by the authors.This study was supported by JSPS KAKENHI (23590223), and partly supported by “the Center of Innovation Program from Japan Science and Technology Agency, JST” for MRI study.

Supplementary material

Supplementary figure is available via the “Supplementary” tab on the article's online page (http://dx.doi.org/10.1080/1357650X.2015.1047379).