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Substance use disorder (SUD) – including substance abuse and dependence - is characterized by impairments in a range of emotional and cognitive processes, mediated by imbalanced communication across distributed brain networks. In this meta-analysis, we aim to include resting-state studies from previous case-control studies comparing individuals with SUD and healthy control subjects to specify robust patterns of aberrant brain functional connectivity.

Compulsivity represents an underlying behavioral dysregulation across obsessive-compulsive disorder, substance use disorders. The present meta-analysis aims at determining common grey matter (GM) deficits in these disorders by capitalizing on previous voxel-based morphometry studies conducted in individuals with obsessive-compulsive disorder (OCD) and substance use disorders (SUD).

In the current diagnostic systems for mental disorders (e.g. DSM-5), anxiety disorders encompass a phenomenologically heterogenous group of disorders. Some of the diagnostic entities subsumed under anxiety disorders are predominantly characterized by exaggerated anxiety (i.e. Generalized Anxiety Disorder, GAD) while other disorders are characterized by exaggerated fear (i.e. phobic and panic disorders) (Vahabzadeh et al., 2015). Previous meta-analytic studies examining brain-structural alterations in anxiety disorders either focused on specific anxiety disorders (e.g., Kolesar et al., 2019; Wang et al., 2018; Wu et al., 2018) or pooled data from all types of anxiety disorders (e.g. Shang et al., 2014). Moreover, epidemiological, symptomatic and pathogenetic perspectives suggest a strong overlap between GAD and Major Depressive Disorder (MDD), leading to a continuous debate about their nosological and neurobiological uniqueness and the categorization of GAD as primary anxiety disorder. Against this background, the present meta-analysis aims at determining common and distinct grey matter (GM) abnormalities between generalized anxiety disorder (GAD) , fear-related disorders (i.e., social anxiety disorder (SAD), panic disorder (PD), specific phobia (SP) and post-traumatic stress disorder (PTSD)) and major depression (MDD). To this end the present meta-analysis capitalizes on previous case control studies employing voxel-based morphometry (VBM) to determine the common and distinct brain structural alterations in patients with these disorders relative to healthy controls. Note that the meta-analysis on fear-related disorders includes SAD, PD, SP and PTSD. The search terms for fear-related anxiety disorders are: “Social Anxiety Disorder” OR “Social phobia” OR “Specific phobia” OR “panic disorder” OR “Phobia” OR “agoraphobia” OR "post-traumatic stress disorder" OR "PTSD" AND (“voxel-based morphometry” OR “VBM”).

During the past two decades several brain imaging studies have examined the neural correlates of disgust (the first study employing functional MRI was published by Phillips et al. (Phillips et al., 1997)). These studies usually combined the presentation of disgust-associated stimuli during neuroimaging acquisition and examined associated increases in regional brain activity. However, the original studies reported a number of different brain regions and it is still a matter of debate which regions may underlie disgust processing. On the one hand characteristics of the original studies such as low sample size, lack of power and robustness or differences in the recruited samples may have contributed to the inconsistent findings. On the other hand, differences in the employed stimuli may account for the inconsistent results. Among the previous studies, different kinds of stimuli have been employed, which could be classified into two main domains. The first domain contains facial expressions of disgust and film clips (also, static and dynamic disgust facial expressions) depicting disgusted facial expressions on the basis of their ability to evoke a vicarious experience of disgust, the second domain includes generally disgust-inducing pictures and film clips (also, static and dynamic disgust elicitors) which can evoke strong disgust-related feelings. The static and dynamic disgusted facial expressions carry strong socially communicative and interpersonal meaning and convey the experience of disgust of the depicted person to the observer whereas the disgusting stimuli induce directly a disgusting experience in the observer. It is therefore conceivable that the stimuli which vary along a social dimension (non-social, direct disgust inducing stimuli vs social communicative and interpersonal disgust stimuli) may induce differential as well as common neural activity. Despite a large number of disgust-related fMRI studies there is to our knowledge not a single neuroimaging meta-analysis that capitalized on the previous original studies to robustly determine the neural correlates of disgust processing or differences between the social and non-social disgust stimuli. To this end the present activation likelihood estimation (ALE) meta-analysis aims at investigating brain regions engaged during disgust processing in healthy subjects and to determine common and distinct neural correlates along the social and non-social dimensions. The ALE meta-analysis approach is not limited by experimental design, paradigm, task, number of subjects and data analysis methods (Eickhoff, Bzdok, Laird, Kurth, & Fox, 2012; Laird et al., 2005; Wager, Lindquist, & Kaplan, 2007), thus allowing general inferences to be drawn, which can help to resolve previous inconsistencies in the literature.

The first neuroimaging meta-analysis on cognitive benefits of exercise intervention through activation likelihood estimation (ALE).

This is a coordinate based meta-analysis on fMRI reward processing in depression.