The meta-analysis by Wager and Smith (2003) examines the neural basis of working memory (WM) across 60 neuroimaging studies using PET and fMRI. The study considers three types of storage material (spatial, verbal, and object) and three types of executive functions (continuous updating, memory for temporal order, and manipulation of information). Key findings include: 1. **Material Type Dissociation**: Spatial and nonspatial storage show a dorsal-ventral dissociation in the posterior cortex, with spatial storage preferentially activating the superior parietal cortex and nonspatial storage activating the inferior temporal cortex. Verbal storage shows left lateralization, particularly in the left frontal cortex. 2. **Executive Functions**: Executive demand increases right lateralization in the frontal cortex for spatial WM. Tasks requiring executive processing generally produce more dorsal frontal activations than storage-only tasks. Brodmann's areas (BAs) 6, 8, and 9 in the superior frontal cortex are involved in continuous updating and memory for temporal order. BAs 10 and 47 in the ventral frontal cortex are more active with demand for manipulation. BA 7 in the posterior parietal cortex is involved in all types of executive function. 3. **Selective Attention**: Selective attention to features of a stimulus to be stored in WM leads to increased activation in the medial prefrontal cortex (BA 32). The study uses quantitative meta-analysis techniques, including chi-square analysis and cluster analysis, to test for differences in regional activation based on material type and executive requirements. The results provide a comprehensive understanding of the neural mechanisms underlying WM and highlight the importance of considering both material type and executive function in WM research.The meta-analysis by Wager and Smith (2003) examines the neural basis of working memory (WM) across 60 neuroimaging studies using PET and fMRI. The study considers three types of storage material (spatial, verbal, and object) and three types of executive functions (continuous updating, memory for temporal order, and manipulation of information). Key findings include: 1. **Material Type Dissociation**: Spatial and nonspatial storage show a dorsal-ventral dissociation in the posterior cortex, with spatial storage preferentially activating the superior parietal cortex and nonspatial storage activating the inferior temporal cortex. Verbal storage shows left lateralization, particularly in the left frontal cortex. 2. **Executive Functions**: Executive demand increases right lateralization in the frontal cortex for spatial WM. Tasks requiring executive processing generally produce more dorsal frontal activations than storage-only tasks. Brodmann's areas (BAs) 6, 8, and 9 in the superior frontal cortex are involved in continuous updating and memory for temporal order. BAs 10 and 47 in the ventral frontal cortex are more active with demand for manipulation. BA 7 in the posterior parietal cortex is involved in all types of executive function. 3. **Selective Attention**: Selective attention to features of a stimulus to be stored in WM leads to increased activation in the medial prefrontal cortex (BA 32). The study uses quantitative meta-analysis techniques, including chi-square analysis and cluster analysis, to test for differences in regional activation based on material type and executive requirements. The results provide a comprehensive understanding of the neural mechanisms underlying WM and highlight the importance of considering both material type and executive function in WM research.