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Background: Paediatric bipolar disorder (PBD) is characterized by severe mood fluctuations that deviate from typical childhood emotional development. Despite the efforts, the pathophysiology of this disorder is not well understood yet. In this review, we aimed to synthesize existing diffusion magnetic resonance imaging (dMRI) research findings in PBD., Methods: A literature search was conducted using PubMed, Embase, Scopus, and Web of Science databases to identify relevant studies published before April 2024., Results: A total of 23 studies were included in the review. The findings showed variations of fractional anisotropy (FA), axial diffusivity, radial diffusivity, and apparent diffusion coefficient in PBD compared to healthy controls (HCs). Key findings included decreased FA in the anterior cingulate, anterior corona radiata, and corpus callosum, particularly the genu, which correlated with clinical symptoms. Furthermore, longitudinal studies emphasized the significance of the uncinate fasciculus as having atypical developmental trajectories in PBD compared to HCs. In addition, graph analysis revealed widespread changes in structural connectivity, especially affecting the orbitofrontal cortex, frontal gyrus, and basal ganglia. Lastly, machine learning models showed promising results in differentiating PBD from HCs., Limitations: Cross-sectional design of the studies, small sample sizes, and different imaging protocols preclude integration of the findings., Conclusion: PBD seems to be associated with widespread structural changes compared to HC. Understanding these changes, which might account for the clinical manifestations of this disorder, increase our knowledge of the neurobiological underpinnings of PBD. This, in turn, may help develop more effective treatments for this disorder., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The early years after the onset of psychotic disorders, known as "early psychosis" (EP) are critical to determining the path of psychosis trajectory. We used a Diffusion Magnetic Resonance Imaging (DMRI) connectometry approach to assess the microstructural changes of white matter (WM) associated with EP., Methods: We used the Human Connectome Project in Early Psychosis (HCP-EP) dataset to collect DMRI data from patients with EP. The imaging data were processed in the Montreal Neuroimaging Initiative space and transformed into quantitative anisotropy (QA). The QA value was translated into the WM connectivity of each tract and used in the subsequent analysis., Results: 121 patients with EP (94 non-affective/27 affective) and 56 healthy controls were recruited. EP was associated with increased QA in the body and tapetum of corpus callosum (CC) and decreased QA in the bilateral cerebellum, and middle cerebellar peduncle. Compared to non-affective psychosis, affective psychosis showed increased QA in the bilateral cerebellum and vermis and decreased QA in the forceps minor, body of CC, right cingulum, and bilateral inferior fronto-occipital fasciculus. Furthermore, QA changes in several WM tracts were correlated with positive and negative symptom scale scores., Limitations: DMRI intrinsic limitations, limited sample size, and neurobiological effects of psychotropic treatment., Conclusions: EP is associated with alterations in WM connectivity primarily in the CC and cerebellar regions. Also, affective and non-affective psychosis have distinct alterations in WM connectivity. These results can be used for the early diagnosis and differentiation of psychotic disorders., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Social anxiety disorder (SAD) is a psychiatric condition characterized by impaired social functioning that negatively impacts individuals' quality of life. Previous neuroimaging studies have revealed morphological and functional changes in various brain regions associated with SAD. Recent advances in diffusion tensor imaging (DTI) and diffusion-weighted imaging (DWI) have enabled the investigation of microstructural white matter (WM) alterations in SAD. This study aims to provide an overview of DTI/DWI studies exploring WM microstructure changes in SAD., Methods: A systematic search on PubMed, Scopus, Web of Science, and PsycINFO was conducted for relevant records on July 8, 2023. An exploratory meta-analysis was also performed., Results: Eight studies were reviewed. Consistent findings indicated reduced fractional anisotropy and increased diffusivity measures in different WM tracts in SAD patients compared to healthy controls. These alterations were mostly observed within regions of the fronto-limbic network, like uncinate fasciculus (UF) and superior and inferior longitudinal fasciculi (SLF and ILF). Finally, our exploratory meta-analysis on four studies utilizing a voxel-wise analytic approach yielded no significant differences between SAD patients and controls., Limitations: Limited number of studies, small sample sizes, and heterogeneity in analysis methods., Conclusions: Patients with SAD exhibited altered WM integrity, particularly in the UF, SLF, and ILF, compared to healthy controls. However, due to the limited number of included studies, our meta-analysis yielded no significant differences between SAD patients and controls. Therefore, future research is crucial to unravel the link between altered WM structure and the involvement of other limbic and cortical structures in SAD pathogenesis., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Understanding the microstructure of the brain that underlies emotions is of pivotal importance for psychology and psychiatry. Herein, we investigated white matter (WM) tracts associated with anger using the diffusion magnetic resonance imaging (DMRI) connectometry approach while exploring potential sex differences., Methods: 225 healthy participants from the LEMON database were evaluated using the State-Trait Anger Expression Inventory (STAXI). WM images were prepared and analyzed with DMRI. Multiple regression models were fitted to address the correlation of local connectomes with STAXI components with age and handedness as covariates., Results: There were no statistically significant differences in state anger and trait anger between males and females (p = 0.55 and 0.30, respectively). DMRI connectometry revealed that quantitative anisotropy (QA) values in the bilateral corticospinal tract (CST), splenium of corpus callosum (SCC), middle cerebellar peduncle, left inferior cerebellar peduncle, left cingulum, and left fornix were negatively correlated with trait anger and trait anger temperament (TAT) in males. In contrast, the QA values in the bilateral CST and SCC showed a positive correlation with trait anger and TAT in females, which, however, did not reach statistical significance., Limitations: The cross-sectional design and self-reported measures of anger limit the generalizability of our results., Conclusions: This is the first DMRI connectometry study to investigate WM circuits involved in anger. We found that the pathways associated with the limbic system and movement-related regions were involved in trait anger and anger expression in men, while no brain pathways showed a significant relationship with anger in women., Competing Interests: Conflict of interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Treatment-resistant depression (TRD) is a severe disorder characterized by high relapse rates and decreased quality of life. An effective strategy in the management of TRD is deep brain stimulation (DBS), a technique consisting of the implantation of electrodes that receive a stimulation via a pacemaker-like stimulator into specific brain areas, detected through neuroimaging investigations, which include the subgenual cingulate cortex (sgCC), basal ganglia, and forebrain bundles. In this context, to improve our understanding of the mechanism underlying the antidepressant effects of DBS in TRD, we collected the results of diffusion tensor imaging (DTI) studies exploring how WM microstructure is associated with the therapeutic effects of DBS in TRD. A search on PubMed, Web of Science, and Scopus identified 11 investigations assessing WM microstructure in responders and non-responders to DBS. Altered WM microstructure, particularly in the sgCC, medial forebrain bundle, cingulum bundle, forceps minor, and uncinate fasciculus, was associated with the antidepressant effect of DBS in TRD. Overall, the results show that DBS targeting selective brain regions, including the sgCC, forebrain bundle, cingulum bundle, rectus gyrus, anterior limb of the internal capsule, forceps minor, and uncinate fasciculus, seem to be effective for the treatment of TRD.

The pathophysiology of migraine as a headache disorder is still undetermined. Diffusion tensor imaging (DTI) has significantly improved our knowledge about brain microstructure in this disease. Here, we aimed to systematically review DTI studies in migraine and survey the sources of heterogeneity by investigating diffusion parameter changes associated with clinical characteristics and migraine subtypes. Microstructural changes, as revealed by widespread alteration of diffusion metrics in white matter (WM) tracts, subcortical and cortical regions, were reported by several migraine DTI studies. Specifically, we reported changes in the corpus callosum, thalamic radiations, corona radiata, and brain stem. These alterations showed high variability across migraine cycle phases. Additionally, migraine associated with depressive/anxiety symptoms revealed significant changes in the corpus callosum, internal capsule, and superior longitudinal fasciculus. No significant WM microstructural differences were observed between migraine patients with and without aura. Overall, differences between chronic and episodic migraine showed inconsistency across studies. Migraine is associated with microstructural changes in widespread regions including thalamic radiations, corpus callosum, and brain stem. These alterations can highlight neuronal damage and neuronal plasticity mechanisms either following pain stimulations occurring in migraine cycle or as a compensatory response to pain in chronic migraine. Longitudinal studies applying advanced modalities may shed new light on the underlying microstructural changes in migraine subtypes., (© 2022. The Author(s).)

Perinatal Depression (PND) is a severe mental disorder that appears during pregnancy or in the post-partum. Although PND has been associated with behavioral problems in the offspring, its effects on brain development are unclear. With this review we aimed at summarizing the existing literature on the effects of perinatal depressive symptoms on children's brains. A search on PubMed and Embase of structural, functional Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI) studies exploring the effect of PND on offspring's brain was conducted. We selected twenty-six studies, ten structural MRI, five DTI, six fMRI and five with combined techniques. Overall, the studies showed: a) gray matter alterations in amygdala and fronto-temporal lobes; b) microstructural alterations in amygdala, frontal lobe, cingulum, longitudinal fasciculus and fornix; and c) functional alterations between limbic and mesocortical networks. The small sample size and the heterogeneity in populations and methodologies limit this review. In conclusion, PND seems to influence structure and function of offspring, that may contribute to the risk of behavioral disturbances later in life., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

22q11.2 deletion syndrome (22q11DS) is a severe genetic syndrome characterized by cognitive deficits and neuropsychiatric disorders, particularly schizophrenia. Neuroimaging alterations have been extensively reported in 22q11DS, both in gray and white matter structures. However, a considerable variability among the results affects the generalizability of the findings to date. Herein, we reviewed diffusion tensor imaging (DTI) findings in 22q11DS, their association with psychosis and cognition, and the implications of DTI studies on neurodevelopment in 22q11DS. We also investigated differences between 22q11DS and schizophrenic patients without 22q11DS. Using an online search of PubMed and Embase, we identified studies investigating DTI findings in 22q11DS. After selecting eligible studies in accordance with the preferred reporting items for systematic reviews and meta-analyses guideline, we included thirty-one studies. Overall, 22q11DS patients show altered structural connectivity and disrupted microstructural organization of most cortical and subcortical structures and white matter tracts. Moreover, despite a significant heterogeneity in the results, reduced diffusivity measures and elevated fractional anisotropy were observed. However controversial, compared to typically developing children, 22q11DS patients reached the peak of fractional anisotropy (FA) and the trough of radial diffusivity (RD) at an older age, which shows neurodevelopmental delay. DTI measures were also associated with psychotic symptoms and cognitive deficits. In conclusion, this study provides a comprehensive review of microstructural alterations in 22q11DS. Future larger investigations on this syndrome could potentially lead to the detection of early diagnostic imaging markers for genetically induced schizophrenia, thus improving the treatment and, ultimately, the outcome., Competing Interests: Declaration of Competing Interest None of authors has any financial and personal relationships with other people or organizations to report that could inappropriately influence or bias this work., (Copyright © 2021. Published by Elsevier B.V.)