A quantitative meta-analysis of fMRI studies investigating emotional processing in excessive worriers: Application of activation likelihood estimation analysis

Background: Excessive worry is a highly impairing cognitive activity which features a range of psychological disorders. Investigations of its disturbed underlying neural mechanisms have presented largely heterogeneous results. This quantitative neuroimaging meta-analysis aims to identify consistent functional disturbances in emotional processing associated with excessive worry across previously published studies. Methods: We used the activation likelihood estimation (ALE) method to test for significant convergence across findings of 16 neuroimaging experiments reporting functional aberrations during emotional processing between individuals experiencing high versus normal levels of worry. Results: Results demonstrated convergent aberrations in high compared to normal worriers mainly in a left-hemispheric cluster comprising parts of the middle frontal gyrus, inferior frontal gyrus and anterior insula. Behavioral characterization indicated the identified cluster to be associated with language processing and memory, while meta-analytic connectivity mapping yielded strong functional connections between the observed convergent regions and parts of the salience network as well as the default mode network. Limitations: The ALE method cannot consider findings based on regions of interest analyses and studies without significant group differences. Conclusion: Our results indicate that in response to emotional contexts worry prone individuals exhibit disturbed functioning in brain areas which are possibly associated with deviant inner speech processes experienced by these individuals. The observed clusters may further constitute key nodes within interacting neural networks that support internally and externally oriented cognition and control the dynamic interplay among these processes.