[Meta-analyses in clinical brain research]

Positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) have brought about an immense increase in findings on the localization of motor, cognitive, and affective processes in the human brain. However, considerable discrepancy still exists between the multitude of available studies and the limited validity of the individual experiments. Quantitative, coordinate-based meta-analyses are suited to objectively integrate these numerous findings as completely as possible. There are a number of different methods for coordinate-based voxel-wise meta-analyses, but the technique of"activation likelihood estimation" (ALE) has largely prevailed. This contribution describes the principles, methods, and statistical analysis of ALE meta-analyses and their potential for basic research in neuroscience and clinical brain research.