SDM reference manual

Introduction

This manual focuses on the software developed for the Signed Differential Mapping (SDM) method, an improved meta-analytic approach for voxel-based neuroimaging studies. Please read "Voxel-wise meta-analysis of grey matter changes..." at the British Journal of Psychiatry and "Meta-analytical comparison of voxel-based..." at the Archives of General Psychiatry for more information on the method.

Index

	Introduction	Summary of the method and its main features.
	Changes in v1.21	Changes in the behaviour of SDM software in v1.21 as compared to previous versions.
	Preparation	Retrieved neuroimaging data must be included in a folder (see Preparing the folder), and information on samples, groups or variables must be introduced in the SDM table (see Creation of the SDM table). The last step of the preparation is the preprocessing of the studies and their Monte Carlo randomizations (see Preprocessing).
	Globals analysis	You can conduct a (rather simple) meta-analysis of the global variables, e.g. the global gray matter in a meta-analysis of VBM studies, optionally adjusting for groups or covariates.
	Calculations	It is possible to calculate meta-analytic means (see Mean analyses), quartiles (see Descriptive analysis of quartiles), jackknife sensitivity analysis (see Jackknife sensitivity analysis), comparisons between groups including covariates (see Linear model analyses: comparing groups) and meta-regressions (see Linear model analyses: meta-regression).
	Results	Results from previous calculations can be thresholded obtaining meta-analytic peak coordinates, clusters breakdowns and NIfTI (Analyze-compatible) images (see Thresholding the results) which will be authomatically open in an MRIcron template (see Settings). Results can also be extracted extracted from a Talairach label or coordinate (see Extracting masked values) using a mask (see Creation of a mask).
	Batch processing	At the moment only one parameter must be specified to run SDM, the brain viewer, useful for authomatically seeing the results with MRIcron after thresholding.
	Settings	At the moment only one parameter must be specified to run SDM, the brain viewer, useful for authomatically seeing the results with MRIcron after thresholding.
	Running SDM as SPM extension	SDM can also be run as an SPM (Statistical Parametric Mapping) extension.
	How to cite	We have invested a lot of time and effort in creating SDM, please cite it when using it for a meta-analysis.
	Troubleshooting	Reported problems and solutions in SDM software.

The authors | IoP King's College London | NeuroImageN