A 12-step user guide for analyzing voxel-wise gray matter asymmetries in statistical parametric mapping (SPM)

Nat Protoc. 2015 Feb;10(2):293-304. doi: 10.1038/nprot.2015.014. Epub 2015 Jan 15.


Voxel-based morphometry (VBM) has been proven capable of capturing cerebral gray matter asymmetries with a high (voxel-wise) regional specificity. However, a standardized reference on how to conduct voxel-wise asymmetry analyses is missing. This protocol provides the scientific community with a carefully developed guide describing, in 12 distinct steps, how to take structural images from data pre-processing, via statistical analysis, to the final interpretation of the significance maps. Key adaptations compared with the standard VBM workflow involve establishing a voxel-wise hemispheric correspondence, capturing the direction and degree of asymmetry and preventing a blurring of information across hemispheres. The workflow incorporates the most recent methodological developments, including high-dimensional spatial normalization and partial volume estimations. Although the protocol is primarily designed to enable relatively inexperienced users to conduct a voxel-based asymmetry analysis on their own, it may also be useful to experienced users who wish to efficiently adapt their existing scripts or pipelines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain Mapping / methods*
  • Gray Matter* / anatomy & histology
  • Humans
  • Image Processing, Computer-Assisted / methods*
  • Magnetic Resonance Imaging*
  • Mathematical Computing
  • Workflow