A comparison of label‐based review and ALE meta‐analysis in the Stroop task

Abstract

Meta-analysis is an important tool for interpreting results of functional neuroimaging studies and is highly influential in predicting and testing new outcomes. Although traditional label-based review can be used to search for agreement across multiple studies, a new functionlocation meta-analysis technique called activation likelihood estimation (ALE) offers great improvements over conventional methods. In ALE, reported foci are modeled as Gaussian functions and pooled to create a statistical whole-brain image. ALE meta-analysis and the label-based review were used to investigate the Stroop task in normal subjects, a paradigm known for its effect of producing conflict and response inhibition due to subjects' tendency to perform word reading as opposed to color naming. Both methods yielded similar activation patterns that were dominated by response in the anterior cingulate and the inferior frontal gyrus. ALE showed greater involvement of the anterior cingulate as compared to that in the label-based technique; however, this was likely due to the increased spatial level of distinction allowed with the ALE method. With ALE, further analysis of the anterior cingulate revealed evidence for somatotopic mapping within the rostral and caudal cingulate zones, an issue that has been the source of some conflict in previous reviews of the anterior cingulate cortex. Hum Brain Mapp 25:6 -21, 2005.

Automated analysis of meta‐analysis networks

“…Experiments using verbal response had the highest similarity with node 5 (left inferior frontal gyrus, BA44). These response-to-node relationships, based only on ranking of similarity coefficients from the pooled Stroop meta-analysis data, are consistent with findings from the more detailed verbal and manual Stroop meta-analyses reported in Table V of Laird et al [2005a].…”

“…These subsets are special subnets of the meta-analysis network. As such, anterior and posterior rostral caudate zones rCZa (node 8) and rCZp (node 1) were naturally parcellated into different subnets, consistent with the somatotopic assignments reported by Laird et al [2005a]. Inspection of Table VI shows that node 8 (rCZa) was reported most often in experiments using manual response with nonlexical or combined controls whereas node 1 (rCZp) was reported with similar incidence among control and response types, i.e., most involved with the paradigm.…”

“…These nodes were most often reported in experiments using nonlexical or combination-type control and manual response (Table VI). Although not providing the level of detail as seen in Figure 6 in Laird et al [2005a], these findings are important because they were obtained using pooled Stroop data without separate verbal and manual Stroop analyses.…”

“…When multiple studies are pooled in a voxel-based ALE meta-analysis, not all regions (network nodes) are activated in each contributing study (e.g., see Table II in Turkeltaub et al [2002] and Table VI in Laird et al [2005a]). Although it is possible that the pattern of presences/absences is random, it is far more likely that occurrence patterns are meaningful, reflecting interpretable variations among the studies.…”

Beyond hypofrontality: A quantitative meta‐analysis of functional neuroimaging studies of working memory in schizophrenia

“…ALE is a voxel-based method for finding concordance within a neuroimaging literature that does not rely upon author-assigned anatomical labels [Laird et al, 2005b]. Rather, the ALE method requires only that activation foci be reported in standard stereotactic space.…”