The Insula: An Underestimated Brain Area in Clinical Neuroscience, Psychiatry, and Neurology

Neural correlates of communication modes in medical students using fMRI

This study aims to determine if the six different types of communication (Directive, Imaginative, Reflective, Persuasive, Harmonizing, Promoting), as presented in the Process Communication Model, correlate with a respective neural pathway. Participants were 30 medical students with no past medical history. They underwent functional magnetic resonance imaging (fMRI) while watching videos typical of each communication type. By comparing each of the six experimental conditions with all the other ones, common activations were detected in the core memory network. Assertive communication styles (Directive, Imaginative) generated activations in conflict detection and resolution related areas, with a predominance in the frontal lobe. Emotive communication (Harmonizing, Promoting) highlighted activations associated with the interpretation of social and emotional cues, with a temporo-occipital predominance. There were no significant activations for the Reflective and Persuasive channel, the two channels that were most coherent with the subjects' base patterns and communication. This study indicated that out of the six communication types that were analyzed, four have a specific and congruous underlying cerebral process. This shows that neural response patterns vary across different communication styles, reflecting differences in cognitive and emotional processing.

Brain structural correlates of an impending initial major depressive episode

Neuroimaging research has yet to elucidate whether reported gray matter volume (GMV) alterations in major depressive disorder (MDD) exist already before the onset of the first episode. Recruitment of presently healthy individuals with a subsequent transition to MDD (converters) is extremely challenging but crucial to gain insights into neurobiological vulnerability. Hence, we compared converters to patients with MDD and sustained healthy controls (HC) to distinguish pre-existing neurobiological markers from those emerging later in the course of depression. Combining two clinical cohorts (n = 1709), voxel-based morphometry was utilized to analyze GMV of n = 45 converters, n = 748 patients with MDD, and n = 916 HC in a region-of-interest approach and exploratory whole-brain. By contrasting the subgroups and considering both remission state and reported recurrence at a 2-year clinical follow-up, we stepwise disentangled effects of (1) vulnerability, (2) the acute depressive state, and (3) an initial vs. a recurrent episode. Analyses revealed higher amygdala GMV in converters relative to HC (ptfce-FWE = 0.037, d = 0.447) and patients (ptfce-FWE = 0.005, d = 0.508), remaining significant when compared to remitted patients with imminent recurrence. Lower GMV in the dorsolateral prefrontal cortex (ptfce-FWE < 0.001, d = 0.188) and insula (ptfce-FWE = 0.010, d = 0.186) emerged in patients relative to HC but not to converters, driven by patients with acute MDD. By examining one of the largest available converter samples in psychiatric neuroimaging, this study allowed a first determination of neural markers for an impending initial depressive episode. Our findings suggest a temporary vulnerability, which in combination with other common risk factors might facilitate prediction and in turn improve prevention of depression.

Symptom perception in adults with chronic physical disease: A systematic review of insular impairments

BACKGROUND

To perform self-care, individuals with a chronic illness must be able to perceive bodily changes (ie., interoception) so they can respond to symptoms when they arise. Interoception is regulated by the insular cortex of the brain. Symptom perception is poor in various physical diseases, which may be associated with impairments in the insular cortex.

OBJECTIVE

The purpose of this study was to explore whether patterns of insular impairment exist among adults with chronic physical diseases and to analyze the relationship with disease-related symptoms.

METHODS

We identified studies that assessed the structure and/or activity of the insula through MRI and/or (f)MRI in adults with chronic physical diseases (vs. healthy controls) by searching five databases. Results are reported as a narrative synthesis.

RESULTS

Fifty studies were conducted to investigate the structure or activity of the insula among adults with diabetes, cancer, heart failure, or chronic pulmonary disease. In 19 studies investigators found that patients with a chronic disease had lower/damaged insular volume/density/thickness than healthy controls or reduced insular blood flow. When insular activity was explored in 22 studies, most investigators reported higher insular activity and lower neural connectivity. Five studies explored the association between insular volume/activity and symptom severity: four reported a positive trend.

CONCLUSION

People with chronic physical diseases have lower insular grey matter volume/density/thickness and abnormal insular activity when compared to healthy people. Insular activity may be related to symptom severity. These results suggest that insular structure and/or activity may explain poor symptom perception.

Bridging the gap: The endocannabinoid system as a functional fulcrum for benzodiazepines in a novel frontier of anxiety pharmacotherapy

While benzodiazepines have been a mainstay of the pharmacotherapy of anxiety disorders, their short-term efficacy and risk of abuse have driven the exploration of alternative treatment approaches. The endocannabinoid (eCB) system has emerged as a key modulator of anxiety-related processes, with evidence suggesting dynamic interactions between the eCB system and the GABAergic system, the primary target of benzodiazepines. According to the existing literature, the activation of the cannabinoid receptors has been shown to exert anxiolytic effects, while their blockade or genetic deletion results in heightened anxiety-like responses. Moreover, studies have provided evidence of interactions between the eCB system and benzodiazepines in anxiety modulation. For instance, the attenuation of benzodiazepine-induced anxiolysis by cannabinoid receptor antagonism or genetic variations in the eCB system components in animal studies, have been associated with variations in benzodiazepine response and susceptibility to anxiety disorders. The combined use of cannabinoid-based medications, such as cannabinoid receptor agonists and benzodiazepine co-administration, has shown promise in augmenting anxiolytic effects and reducing benzodiazepine dosage requirements. This article aims to comprehensively review and discuss the current evidence on the involvement of the eCB system as a key modulator of benzodiazepine-related anxiolytic effects, and further, the possible mechanisms by which the region-specific eCB system-GABAergic connectivity modulates the neuro-endocrine/behavioral stress response, providing an inclusive understanding of the complex interplay between the eCB system and benzodiazepines in the context of anxiety regulation, to inform future research and clinical practice.

Effectiveness of mindfulness-based online therapy or internet-delivered cognitive behavioral therapy compared with treatment as usual among patients with persistent somatic symptoms: Protocol for a randomized controlled trial

BACKGROUND

Persistent somatic symptoms unexplained by a defined medical or psychiatric condition often include a component of central sensitization. Many treatment options are based on cognitive behavioral therapy. Effective widely available therapies are scarce. There are self-management programs and e-therapies that aim at overcoming the central sensitization by modifying interoceptive neural networks in the brain.

OBJECTIVES

This study aims to investigate the effect of a mindfulness-based amygdala and insula retraining (AIR) online program and an internet delivered therapist assisted therapy offered by Helsinki University Hospital (HUS iCBTpss) compared to treatment as usual (TAU) in the treatment of conditions causing persistent somatic symptoms.

METHODS

We will perform a randomized controlled trial aiming at 360 patients. Consenting patients will be randomized to three study arms: online AIR program, HUS iCBTpss (both interventions as add-ons to TAU); and TAU. Functional ability and quality of life surveys will be collected from participants at baseline and at 3, 6, and 12 months after entering the study.

CONCLUSIONS

This study is one of the first to explore non-drug based online interventions developed to overcome the brain's central sensitization and are available and accessible to patients both in primary and secondary care. The results will develop the management of the common, often debilitating persistent somatic symptoms related to many conditions unexplained by a defined somatic or psychiatric illness.

TRIAL REGISTRATION NUMBER

NCT05212467.

Effects of intranasal oxytocin on fear extinction learning

Once a threat no longer exists, extinction of conditioned fear becomes adaptive in order to reduce allotted resources towards cues that no longer predict the threat. In anxiety and stress disorders, fear extinction learning may be affected. Animal findings suggest that the administration of oxytocin (OT) modulates extinction learning in a timepoint-dependent manner, facilitating extinction when administered prior to fear conditioning, but impairing it when administered prior to extinction learning. The aim of the present study was to examine if these findings translate into human research. Using a randomized, double-blind, placebo-controlled, 2-day fear conditioning and extinction learning design, behavioral (self-reported anxiety), physiological (skin conductance response), neuronal (task-based and resting-state functional magnetic resonance imaging), and hormonal (cortisol) data were collected from 124 naturally cycling (taking no hormonal contraceptives) healthy females. When administered prior to conditioning (Day 1), OT, similar to rodent findings, did not affect fear conditioning, but modulated the intrinsic functional connectivity of the anterior insula immediately after fear conditioning. In contrast to animal findings, OT impaired, not facilitated, extinction learning on the next day and increased anterior insula activity. When administered prior to extinction learning (day 2), OT increased the activity in the bilateral middle temporal gyrus, and similar to animal findings, reduced extinction learning. The current findings suggest that intranasal OT impedes fear extinction learning in humans regardless of the timepoint of administration, providing new insights and directions for future translational research and clinical applications.

A stress-activated mid-insula to BNST pathway regulates susceptibility to abstinence-induced negative affect in female mice

Stress is central to many neuropsychiatric conditions, including alcohol use disorder (AUD). Stress influences the initiation and continued use of alcohol, the progression to AUD, and relapse. Identifying the neurocircuits activated during stress, and individual variability in these responses is critical for developing new treatment targets for AUD, particularly to mitigate stress-induced relapse. Using a longitudinal approach, this study examined the relationship between sub-chronic stress exposure and negative affect during protracted abstinence following chronic ethanol exposure. Sub-chronic restraint stress heightened negative affect-like behavior in protracted abstinence. Interestingly, this was driven by a subset of "stress-susceptible" female mice. We examined the mid-insula, a hub in the brain's salience network, as a driver of this effect, given its role in emotional regulation and links to alcohol craving, consumption, and abstinence-induced negative affect. Mid-insula GCaMP fiber photometry revealed that GCaMP activity during stress exposure was positively correlated with activity during the novelty-suppressed feeding test (NSFT) two weeks into abstinence. A distinct subset of mice exhibited increasing activity during the consummatory phase, implicating the mid-insula as a neural basis for heightened negative affect in abstinence. Chemogenetic inhibition of mid-insula neurons projecting to the dorsal BNST during stress disrupted the emergence of stress susceptibility, highlighting this circuit as a key determinant of susceptibility to abstinence-induced negative affect. These outcomes were female-specific, addressing a critical gap in understanding AUD risk in women. Furthermore, female mice exhibited higher struggling behavior during stress than males. However, this effect was blocked by chemogenetic inhibition of the insula-BNST pathway during stress. By linking pre-alcohol stress response with abstinence outcomes, this work positions the insula-BNST pathway as a potential AUD circuit activity biomarker and therapeutic target.

Polygenic risk for depression and resting-state functional connectivity of subgenual anterior cingulate cortex in young adults

BACKGROUND

Genetic variants may confer risk for depression by modulating brain structure and function; evidence has underscored the key role of the subgenual anterior cingulate cortex (sgACC) in depression. We sought to examine how the resting-state functional connectivity (rsFC) of the sgACC was associated with polygenic risk for depression in a subclinical population.

METHODS

Following published protocols, we computed seed-based whole-brain sgACC rsFC and calculated polygenic risk scores (PRS) using data from healthy young adults from the Human Connectome Project. We performed whole-brain regression against PRS and severity of depression symptoms in a single model for all participants and by sex, controlling for age, sex, race or ethnicity, alcohol use severity, and household income. We evaluated the results at a corrected threshold.

RESULTS

We included data for 717 healthy young adults. We found lower rsFC between the sgACC and the default mode network and frontal regions in association with PRS and lower sgACC-cerebellar rsFC in association with depression severity. We also noted differences by sex in the connectivity correlates of PRS and depression severity. In an additional set of analyses, we observed a significant correlation between PRS and somatic complaints, as well as altered sgACC-somatosensory cortical connectivity in association with the severity of somatic complaints.

LIMITATIONS

The current findings should be considered specific to subclinical depression and may not generalize to patients with depressive disorders.

CONCLUSION

Our findings highlight the pivotal role of distinct sgACC-based networks in the genetic predisposition for depression and the manifestation of depression among young adults with subclinical depression. Distinguishing the risk from severity markers of depression may have implications in developing early and effective treatments for people at risk for depression.

Neuroanatomical alterations in young boys and adolescents with Klinefelter syndrome

Klinefelter syndrome (KS, 47,XXY) is a common sex chromosome aneuploidy in males that is characterized by pubertal developmental delays and a wide range of alterations in cognitive, social and emotional functioning. The neural bases of these behavioral symptoms, however, are unclear. A total of 130 boys and adolescents, including 67 males with KS (11.5 ± 2.8 years) and 63 typically developing (TD; control) males (10.6 ± 2.8 years) underwent MRI scanning and pubertal assessment. Group differences in regional gray matter volume was examined using voxel-based morphometry while controlling for age at scan and total gray matter volume. Thresholded statistical significance maps indicated widespread reductions in frontal and temporal and cerebellar gray matter in males with KS relative to TD males, as well as increases in parietal and occipital gray matter. Secondary analyses explored potential associations between GMV in these regions and pubertal development. Lower testicular volume was a significant predictor of reduced GMV in frontal, temporal and cerebellar subregions, even after accounting for group status (KS, TD). Taken together, these findings add support for a neuroanatomical phenotype of KS and provide initial evidence for a role of pubertal development in KS-associated differences in gray matter structure. Future studies that examine the influence of testosterone supplementation on GMV in males with KS are warranted.

Temporary Global Amnesia With Insular Infarction in a Young Female: A Case Report

Several neurological conditions, including transient global amnesia (TGA), may present an isolated sudden-onset temporary amnestic symptom. TGA is a benign, self-remitting neurological condition associated with hippocampal dysfunction. Meanwhile, certain other neurological conditions, such as cerebral ischemic stroke and hippocampal epilepsy, require appropriate therapeutic interventions. An isolated temporary amnestic symptom caused by extra-limbic brain regions has not been widely reported yet. We report a case of a 37-year-old female with systemic lupus erythematosus (SLE) who suddenly developed a transient amnestic symptom, with no other neurological symptoms, during an outdoor activity on a hot sunny day. Anterograde amnesia resolved after approximately two hours from the onset. She visited the hospital three days later. Brain MRI revealed an acute infarction in the left anterior insular cortex. A 2 mm thin-slice MRI on both hippocampi revealed no diffusion restriction. She was diagnosed with insular cortex infarction, possibly associated with SLE. Single antiplatelet therapy with aspirin 100 mg/day was started on the same day and oral prednisolone with 10 mg/day was started on the next day. This report is the first of its kind to describe a possible association between temporary amnesia and insular cortex damage. This case implies that the anterior insular cortex may play a potential role in forming episodic memories. Damages in this area may present a sudden-onset transient amnestic symptom. Clinicians should pay close attention to this non-hippocampal area on brain MRI when investigating amnestic patients.

DFC-Igloo: A dynamic functional connectome learning framework for identifying neurodevelopmental biomarkers in very preterm infants

BACKGROUND AND OBJECTIVE

Very preterm infants are susceptible to neurodevelopmental impairments, necessitating early detection of prognostic biomarkers for timely intervention. The study aims to explore possible functional biomarkers for very preterm infants at born that relate to their future cognitive and motor development using resting-state fMRI. Prior studies are limited by the sample size and suffer from efficient functional connectome (FC) construction algorithms that can handle the noisy data contained in neonatal time series, leading to equivocal findings. Therefore, we first propose an enhanced functional connectome construction algorithm as a prerequisite step. We then apply the new FC construction algorithm to our large prospective very preterm cohort to explore multi-level neurodevelopmental biomarkers.

METHODS

There exists an intrinsic relationship between the structural connectome (SC) and FC, with a notable coupling between the two. This observation implies a putative property of graph signal smoothness on the SC as well. Yet, this property has not been fully exploited for constructing intrinsic dFC. In this study, we proposed an advanced dynamic FC (dFC) learning model, dFC-Igloo, which leveraged SC information to iteratively refine dFC estimations by applying graph signal smoothness to both FC and SC. The model was evaluated on artificial small-world graphs and simulated graph signals.

RESULTS

The proposed model achieved the best and most robust recovery of the ground truth graph across different noise levels and simulated SC pairs from the simulation. The model was further applied to a cohort of very preterm infants from five Neonatal Intensive Care Units, where an enhanced dFC was obtained for each infant. Based on the improved dFC, we identified neurodevelopmental biomarkers for neonates across connectome-wide, regional, and subnetwork scales.

CONCLUSION

The identified markers correlate with cognitive and motor developmental outcomes, offering insights into early brain development and potential neurodevelopmental challenges.

Altered structural and functional homotopic connectivity associated with cognitive changes in SLE

OBJECTIVE

Previous studies have revealed functional changes within the cerebral hemispheres of patients with SLE; however the changes between cerebral hemispheres are still unknown. The present study aimed to explore the functional and structural changes between bilateral hemispheres using functional MRI and find their relationship with cognition in patients with SLE.

METHODS

54 patients with SLE and 32 age-matched and sex-matched healthy controls (HCs) underwent MRI scanning and neuropsychological testing, and clinical data was collected in patients with SLE. Voxel-mirrored homotopic connectivity (VMHC) values and grey matter volume were calculated for all subjects. Correlation analysis was established to determine the relationship between VMHC values, grey matter volume and cognitive scores, blood biochemical markers in patients with SLE.

RESULTS

Compared with HCs, patients with SLE showed increased VMHC values in the insula and parahippocampal gyrus, while grey matter volume were reduced in these regions. Correlation analysis demonstrated that the increased VMHC values in insula was negatively correlated with decreased orientation function and positively correlated with decreased attention function. The grey matter volume in insula was negatively correlated with decreased attention and abstraction. The VMHC values and grey matter volume in insula and parahippocampal gyrus were negatively associated with lupus-specific antibodies.

CONCLUSION

The structural and functional changes of insula and parahippocampal gyrus might be potential neuroimaging markers, and specific antibodies associated with lupus might be involved in the pathophysiological mechanisms of brain dysfunction.

TRIAL REGISTRATION NUMBER

NCT06226324.

Chemogenetic inhibition of pain-related neurons in the posterior insula cortex reduces mechanical hyperalgesia and anxiety-like behavior during acute pain

Pain is a complex phenomenon that involves sensory, emotional, and cognitive components. The posterior insula cortex (pIC) has been shown to integrate multisensory experience with emotional and cognitive states. However, the involvement of the pIC in the regulation of affective behavior in pain remains unclear. Here, we investigate the role of pain-related pIC neurons in the regulation of anxiety-like behavior during acute pain. We combined a chemogenetic approach with targeted recombination in active populations (TRAP) in mice. Global chemogenetic inhibition of pIC neurons attenuates chemically-induced mechanical hypersensitivity without affecting pain-related anxiety-like behavior. In contrast, inhibition of pain-related pIC neurons reduces both mechanical hypersensitivity and pain-related anxiety-like behavior. The present study provides important insights into the role of pIC neurons in the regulation of sensory and affective pain-related behavior.

Prediction and clustering of Alzheimer's disease by race and sex: a multi-head deep-learning approach to analyze irregular and heterogeneous data

Early detection of Alzheimer's disease (AD) is crucial to maximize clinical outcomes. Most disease progression analyses include people with diagnoses of cognitive impairment, limiting understanding of AD risk among those with normal cognition. The objective was to establish AD progression models through a deep learning approach to analyze heterogeneous, multi-modal datasets, including clustering analyses of population subsets. A multi-head deep-learning architecture was built to process and learn from biomedical and imaging data from the National Alzheimer's Coordinating Center. Shapley additive explanation algorithms for feature importance ranking and pairwise correlation analysis were used to identify predictors of disease progression. Four primary disease progression clusters (slow, moderate and rapid converters or non-converters) were subdivided into groups by race and sex, yielding 16 sub-clusters of participants with distinct progression patterns. A multi-head and early-fusion convolutional neural network achieved the most competitive performance and demonstrated superiority over a single-head deep learning architecture and conventional tree-based machine-learning methods, with 97% test accuracy, 96% F1 score and 0.19 root mean square error. From 447 features, 2 sets of 100 predictors of disease progression were extracted. Feature importance ranking, correlation analysis and descriptive statistics further enriched cluster analysis and validation of the heterogeneity of risk factors.

Biomarkers for cognitive impairment in alpha-synucleinopathies: an overview of systematic reviews and meta-analyses

Cognitive impairment (CI) is common in α-synucleinopathies, i.e., Parkinson's disease, Lewy bodies dementia, and multiple system atrophy. We summarize data from systematic reviews/meta-analyses on neuroimaging, neurophysiology, biofluid and genetic diagnostic/prognostic biomarkers of CI in α-synucleinopathies. Diagnostic biomarkers include atrophy/functional neuroimaging brain changes, abnormal cortical amyloid and tau deposition, and cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers, cortical rhythm slowing, reduced cortical cholinergic and glutamatergic and increased cortical GABAergic activity, delayed P300 latency, increased plasma homocysteine and cystatin C and decreased vitamin B12 and folate, increased CSF/serum albumin quotient, and serum neurofilament light chain. Prognostic biomarkers include brain regional atrophy, cortical rhythm slowing, CSF amyloid biomarkers, Val66Met polymorphism, and apolipoprotein-E ε2 and ε4 alleles. Some AD/amyloid/tau biomarkers may diagnose/predict CI in α-synucleinopathies, but single, validated diagnostic/prognostic biomarkers lack. Future studies should include large consortia, biobanks, multi-omics approach, artificial intelligence, and machine learning to better reflect the complexity of CI in α-synucleinopathies.

Multi-domain predictors of grip strength differentiate individuals with and without alcohol use disorder

Grip strength is considered one of the simplest and reliable indices of general health. Although motor ability and strength are commonly affected in people with alcohol use disorder (AUD), factors predictive of grip strength decline in AUD have not been investigated. Here, we employed a data-driven analysis predicting grip strength from measurements in 53 controls and 110 AUD participants, 53 of whom were comorbid with HIV infection. Controls and AUD were matched on sex, age, and body mass index. Measurements included commonly available metrics of brain structure, neuropsychological functioning, behavioural status, haematological and health status, and demographics. Based on 5-fold stratified cross-validation, a machine learning approach predicted grip strength separately for each cohort. The strongest (top 10%) predictors of grip were then tested against grip strength with correlational analysis. Leading grip strength predictors for both cohorts were cerebellar volume and mean corpuscular haemoglobin concentration. Predictors specific to controls were Backwards Digit Span, precentral gyrus volume, diastolic blood pressure, and mean platelet volume, which together significantly predicted grip strength (R2 = 0.255, p = 0.001). Unique predictors for AUD were comorbidity for HIV infection, social functioning, insular volume, and platelet count, which together significantly predicted grip strength (R2 = 0.162, p = 0.002). These cohort-specific predictors were doubly dissociated. Salient predictors of grip strength differed by diagnosis with only modest overlap. The constellation of cohort-specific predictive measurements of compromised grip strength provides insight into brain, behavioural, and physiological factors that may signal subtly affected yet treatable processes of physical decline and frailty.

Meditation and interoception: a conceptual framework for the narrative and experiential self

The concept of the self is complex and there is no consensus on what the self is. However, there are emerging patterns in the literature that point to two different selves, the narrative and experiential self. The narrative self refers to a conceptual or representational knowledge of the self that extends across time and manifests in self-reflection and personality assessments. The experiential self refers to first-person perception, moment-to-moment awareness, embodiment, and a sense of agency. These two selves are reliably linked to two distinct neural circuits, the default mode network (DMN) and the insula and salience network (SN). One of the consistent themes in the meditative and mindfulness literature is a change in the perspective of the self. In this paper, I will review how meditation alters those neural circuits providing a plausible mechanism that can explain the changes in the self. I also propose a rudimentary conceptual framework to account for some of the mixed results found throughout meditation literature.

Low-frequency repetitive transcranial magnetic stimulation for the treatment of post-traumatic stress disorder and its comparison with high-frequency stimulation: a systematic review and meta-analysis

Background

Repetitive transcranial magnetic stimulation (rTMS) showed potentially beneficial effects for the treatment of post-traumatic stress disorder (PTSD). Low-frequency (LF) rTMS decreases neuronal excitability and may have better safety compared to high-frequency (HF) rTMS. However, there lacks meta-analysis specifically focusing on LF rTMS.

Objectives

To specifically explore the efficacy and safety of LF rTMS for treating PTSD.

Methods

Databases including PubMed, EMBASE, MEDLINE, and Web of Science were systematically searched from inception to October 17, 2023. Both randomized controlled trials (RCTs) and open trials of LF rTMS on PTSD were included, and we additionally included RCTs comparing HF rTMS and sham treatment on PTSD. First, we qualitatively summarized parameters of LF rTMS treatment; then, we extracted data from the LF rTMS treatment subgroups of these studies to examine its effect size and potential influencing factors; third, we compared the effect sizes among LF rTMS, HF rTMS and sham treatment through network meta-analysis of RCTs.

Results

In all, 15 studies with a sample size of 542 participants were included. The overall effect size for LF rTMS as a treatment for PTSD was found as Hedges' g = 1.02 (95% CI (0.56, 1.47)). Meta-regression analysis did not reveal any influencing factors. Network meta-analysis showed that compared to sham treatment, only HF rTMS on the right dorsolateral prefrontal cortex (DLPFC) demonstrated a significant advantage in ameliorating PTSD symptoms, while LF rTMS on the right DLPFC showed a trend toward advantage, but the difference was not significant.

Conclusion

The current literature shows LF rTMS has effect in treating PTSD caused by various traumatic events. However, present limited number of RCT studies only showed LF rTMS to have a trend of advantage compared to sham treatment in treating PTSD caused by external traumatic events. In the future, more RCTs are needed to be made to confirm the efficacy of LF rTMS. Additionally, studies are required to elucidate the underlying mechanism in order to further improve its efficacy in different traumatic populations.

PROSPERO registration number

CRD42023470169.

An MRI-based study of the insula in a South African population

PURPOSE

The insula, a cortical structure buried deep within the sylvian fissure, has long posed a surgical challenge. Comprehensive knowledge of the insular anatomy is therefore integral to preoperative planning and safe interventional procedures. Since magnetic resonance imaging (MRI) is a favoured modality for the identification of cerebral structures, this study aimed to investigate the morphology and morphometry of the insula in a South African population, using MRI scans.

METHODS

One-hundred MRI studies of insulae (n = 200 hemispheres) were retrospectively analysed for morphological features and morphometric parameters.

RESULTS

The insulae were predominantly trapezoidal in shape (Laterality: Left: 82%; Right: 78%; Sex: Male: 84%, Female: 76%). The central insular sulcus was almost always "well seen" (Laterality: Left: 97%; Right: 99%; Sex: Male: 99%, Female: 97%). The middle short insular gyrus (MSG) was most variable in visibility, especially when compared across the sexes (p = 0.004). Insular gyri widths were comparable in both cerebral hemispheres; the posterior long gyrus (PLG) presented with the smallest mean widths. Anterior lobule (AL) widths were larger than those of the posterior lobule (PL). Widths of the insular gyri and lobules were generally larger in males than in females. The MSG and PLG widths in the left hemisphere, AL width in the right hemisphere, and the PL width in both hemispheres were significantly larger in males than in females (p = 0.001; p = 0.005; p = 0.041; p = 0.001, p = 0.015, respectively).

CONCLUSION

MRI scans may be used to accurately interpret insular anatomy. The data obtained may aid neurosurgeons to perform safe insula-related surgical procedures.

Subregions of the fusiform gyrus are differentially involved in the attentional mechanism supporting visual mental imagery in depression

BACKGROUND

Impaired visual mental imagery is an important symptom of depression and has gradually become an intervention target for cognitive behavioral therapy.

METHODS

Our study involved a total of 25 healthy controls (HC) and 23 individuals with moderate depressive symptoms (MD). This study explored the attentional mechanism supporting visual mental imagery impairments in depression using the Vividness of Visual Imagery Questionnaire (VVIQ), attentional network test (ANT), and resting-state functional magnetic resonance imaging (rs-fMRI). The intrinsic activity of attention-related regions relative to those supporting visual mental imagery was identified in depression patients. In addition, a meta-analysis was used to describe the cognitive function related to this intrinsic activity.

RESULTS

The global correlation (GCOR) of the right anterior fusiform gyrus (FG) was decreased in depression patients. Attention-related areas were concentrated in the right posterior FG; the anterior and posterior functional connectivity (FC) of the FG was decreased in depression patients. Graph theoretic analysis showed that the degree of the right anterior FG was decreased, the degree of the anterior insula was increased, and the negative connection between these two regions was strengthened in depression patients. In addition, the degree of the right anterior FG, the FC between the subregions of the right FG, and the FC between the right anterior FG and insula were correlated with VVIQ scores; however, this correlation was not significant in depression patients. The meta-analysis suggested that the changes in the anterior FG in depressed patients may stem from difficulties of semantic memory retrieval.

CONCLUSION

The changed intrinsic activity of subregions of the FG relative to the semantic memory retrieval may be associated with visual mental imagery impairments in depression.

Understanding the impact of breathing pattern disorders in difficult-to-treat asthma

INTRODUCTION

Difficult-to-treat asthma is defined as asthma that is uncontrolled despite high-level treatment or requires such treatment to maintain good control and reduce exacerbations. Breathing pattern disorders (BPD) have been reported as a comorbidity in ~ 24-42% % of patients with difficult-to-treat asthma. This narrative review will assess the association, impact, and management of BPD in difficult-to-treat asthma.

AREAS COVERED

We outline current understandings of the nature of difficult-to-treat asthma and BPD. We then review the impact of BPD on difficult-to-treat asthma and Multidisciplinary Team (MDT) approaches to assessing and managing BPD in this patient group. A comprehensive literature search was performed by an asthma specialist MDT including physiotherapists, psychologists, and physicians to create a holistic perspective on this subject.

EXPERT OPINION

BPD exerts significant negative impacts across multiple domains in patients with difficult-to treat asthma. There is a need for further observational, interventional, qualitative and quantitative research to develop better diagnosis, treatment, and awareness of the impacts of BPD including health economic analysis. Studies should develop multimodal approaches that better treat both BPD and associated comorbidities within the multimorbidity framework of difficult-to-treat asthma. Recognizing and addressing BPD should be key elements in future difficult-to-treat asthma management guidelines and clinical practice.

The relationship between brain structure volumes, depressive symptoms and body composition in obese/overweight and normal-/underweight women

Depressive symptoms are highly prevalent and heterogeneous in women. Different brain structures might be associated with depressive symptoms and body composition in women with obesity/overweight and normal-/underweight, although the data is limited. The analysis included 265 women from Bialystok PLUS population study, untreated with antidepressive or antipsychotic medications. The subjects underwent brain magnetic resonance imaging and body composition analysis. Beck Depression Inventory (BDI) score was inversely associated with nucleus accumbens volume (β = -0.217, p = 0.008) in women with BMI ≥ 25 kg/m2, but with insula volume (β = -0.147, p = 0.027) in women with BMI < 25 kg/m2 after adjustment for age and estimated intracranial volume (eTIV). In women with BMI ≥ 25 kg/m2, nucleus accumbens volume was inversely associated with the percentage of visceral fat and BDI score (β = -0.236, p = 0.012, β = -0.192, p = 0.017) after adjustment for age and eTIV. In women with BMI < 25 kg/m2, insula volume was positively associated with total fat-free mass and negatively with the BDI score (β = 0.142, p = 0.030, β = -0.137, p = 0.037) after adjustment for age and eTIV. Depressive symptoms might be associated with nucleus accumbens volume in overweight/obese women, while in normal-/ underweight women-with alterations in insula volume.

Transient Ipsilateral Hemineglect Following Brain Laser Ablation in Patient with Focal Cortical Dysplasia

Sensory integration is the province of the parietal lobe. The non-dominant hemisphere is responsible for both body sides, while the dominant hemisphere is responsible for the contralateral hemi-body. Furthermore, the posterior cingulate cortex (PCC) participates in a network involved in spatial orientation, attention, and spatial and episodic memory. Laser interstitial thermotherapy (LiTT) is a minimally invasive surgery for focal drug-resistant epilepsy (DRE) that can target deeper brain regions, and thus, region-specific symptoms can emerge. Here, we present an 18-year-old right-handed male with focal DRE who experienced seizures characterized by sensations of déjà vu, staring spells, and language disruption. A comprehensive evaluation localized the seizure focus and revealed a probable focal cortical dysplasia (FCD) in the left posterior cingulate gyrus. The patient underwent uneventful LiTT of the identified lesion. Post-operatively, he developed transient ipsilateral spatial neglect and contralateral sensory loss, as well as acalculia. His sensory symptoms gradually improved after the surgery, and he remained seizure-free after the intervention for at least 10 months (until the time of this writing). This rare case of ipsilateral spatial and visual hemineglect post-LiTT in epilepsy underscores the importance of recognizing atypical neurosurgical outcomes and considering individual variations in brain anatomy and function. Understanding the dynamics of cortical connectivity and handedness, particularly in pediatric epilepsy, may be crucial in anticipating and managing neurocognitive effects following epilepsy surgery.

Association between irritable temperament and glucose metabolism in the left insula and the right cerebellum

INTRODUCTION

Affective temperaments are assumed to have biological and neural bases. In the present study, we analyzed 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) images of healthy participants to explore the neural basis of affective temperaments.

METHOD

We utilized data of affective temperament measured by the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire and 18F-FDG PET images of healthy participants from two of our previous studies. A multiple regression analysis was performed to assess the association between 18F-FDG uptake and temperament scores using Statistical Parametric Mapping 12.

RESULTS

The final sample included 62 healthy participants. Whole-brain analysis revealed a cluster of 18F-FDG uptake that was significantly and positively associated with irritable temperament scores in the right cerebellum (Crus II, VIII, and IX). After further adjustment for the other four temperament scores, whole-brain analysis revealed a cluster of 18F-FDG uptake significantly and positively associated with irritable temperament scores in the left insula and right cerebellum (Crus II, VIII, and IX). However, no significant association was found between 18F-FDG uptake and the other four temperaments (depressive, cyclothymic, hyperthymic, and anxious).

CONCLUSIONS

The left insula and right cerebellum of the cerebrocerebellar circuit may be one of the neural bases of irritable temperament.

Neuroimaging Insights: Structural Changes and Classification in Ménière's Disease

OBJECTIVES

This study aimed to comprehensively investigate the neuroanatomical alterations associated with idiopathic Ménière's disease (MD) using voxel-based morphometry and surface-based morphometry techniques. The primary objective was to explore nuanced changes in gray matter volume, cortical thickness, fractal dimension, gyrification index, and sulcal depth in MD patients compared with healthy controls (HC). Additionally, we sought to develop a machine learning classification model utilizing these neuroimaging features to effectively discriminate between MD patients and HC.

DESIGN

A total of 55 patients diagnosed with unilateral MD and 70 HC were enrolled in this study. Voxel-based morphometry and surface-based morphometry were employed to analyze neuroimaging data and identify structural differences between the two groups. The selected neuroimaging features were used to build a machine learning classification model for distinguishing MD patients from HC.

RESULTS

Our analysis revealed significant reductions in gray matter volume in MD patients, particularly in frontal and cingulate gyri. Distinctive patterns of alterations in cortical thickness were observed in brain regions associated with emotional processing and sensory integration. Notably, the machine learning classification model achieved an impressive accuracy of 84% in distinguishing MD patients from HC. The model's precision and recall for MD and HC demonstrated robust performance, resulting in balanced F1-scores. Receiver operating characteristic curve analysis further confirmed the discriminative power of the model, supported by an area under the curve value of 0.92.

CONCLUSIONS

This comprehensive investigation sheds light on the intricate neuroanatomical alterations in MD. The observed gray matter volume reductions and distinct cortical thickness patterns emphasize the disease's impact on neural structure. The high accuracy of our machine learning classification model underscores its diagnostic potential, providing a promising avenue for identifying MD patients. These findings contribute to our understanding of MD's neural underpinnings and offer insights for further research exploring the functional implications of structural changes.

Integrative molecular and structural neuroimaging analyses of the interaction between depression and age of onset: A multimodal magnetic resonance imaging study

Depression is a neurodevelopmental disorder that exhibits progressive gray matter volume (GMV) atrophy. Research indicates that brain development is influential in depression-induced GMV alterations. However, the interaction between depression and age of onset is not well understood by the underlying molecular and neuropathological mechanisms. Thus, 152 first-episode depression individuals and matched 130 healthy controls (HCs) were recruited to undergo T1-weighted high-resolution magnetic resonance imaging for this study. By two-way ANOVA, age and diagnosis were used as factors when analyzing the interaction of GMV in the participants. Then, spatial correlations between neurotransmitter maps and factor-related volume maps are established. Results illustrate a pronounced antagonistic interaction between depression and age of onset in the right insula, superior temporal gyrus, anterior cingulate gyrus, and orbitofrontal gyrus. Depression-caused reductions in GMV are mainly distributed in thalamic-limbic-cortical regions, regardless of age. For the main effect of age, adults exhibit brain atrophy in frontal, cerebellum, parietal, and temporal lobe structures. Cross-modal correlations showed that GMV changes in the interactive regions were linked with the serotonergic system and dopaminergic systems. Summarily, our results reveal the interaction between depression and age of onset in neurobiological mechanisms, which provide hints for future treatment of different ages of depression.

Are older adults less generous? Age differences in emotion-related social decision making

In social interaction, age-related differences in emotional processing may lead to varied social decision making between young and older adults. However, previous studies of social decision making have paid less attention to the interactants' emotions, leaving age differences and underlying neural mechanisms unexplored. To address this gap, the present study combined functional and structural magnetic resonance imaging, employing a modified dictator game task with recipients displaying either neutral or sad facial expressions. Behavioral results indicated that although older adults' overall allocations did not differ significantly from those of young adults, older adults' allocations showing a decrease in emotion-related generosity compared to young adults. Using representational similarity analysis, we found that older adults showed reduced neural representations of recipients' emotions and gray matter volume in the right anterior cingulate gyrus (ACC), right insula, and left dorsomedial prefrontal cortex (DMPFC) compared to young adults. More importantly, mediation analyses indicated that age influenced allocations not only through serial mediation of neural representations of the right insula and left DMPFC, but also through serial mediation of the mean gray matter volume of the right ACC and left DMPFC. This study identifies the potential neural pathways through which age affects emotion-related social decision making, advancing our understanding of older adults' social interaction behavior that they may not be less generous unless confronted with individuals with specific emotions.

Preparatory activity of anterior insula predicts conflict errors: integrating convolutional neural networks and neural mass models

Preparatory brain activity is a cornerstone of proactive cognitive control, a top-down process optimizing attention, perception, and inhibition, fostering cognitive flexibility and adaptive attention control in the human brain. In this study, we proposed a neuroimaging-informed convolutional neural network model to predict cognitive control performance from the baseline pre-stimulus preparatory electrophysiological activity of core cognitive control regions. Particularly, combined with perturbation-based occlusion sensitivity analysis, we pinpointed regions with the most predictive preparatory activity for proactive cognitive control. We found that preparatory arrhythmic broadband neural dynamics in the right anterior insula, right precentral gyrus, and the right opercular part of inferior frontal gyrus (posterior ventrolateral prefrontal cortex), are highly predictive of prospective cognitive control performance.  The pre-stimulus preparatory activity in these regions corresponds to readiness for conflict detection, inhibitory control, and overall elaborate attentional processing. We integrated the convolutional neural network with biologically inspired Jansen-Rit neural mass model to investigate neurostimulation effects on cognitive control. High-frequency stimulation (130 Hz) of the left anterior insula provides significant cognitive enhancement, especially in reducing conflict errors, despite the right anterior insula's higher predictive value for prospective cognitive control performance. Thus, effective neurostimulation targets may differ from regions showing biomarker activity. Finally, we validated our theoretical finding by evaluating intrinsic neuromodulation through neurofeedback-guided volitional control in an independent dataset. We found that left anterior insula was intrinsically modulated in real-time by volitional control of emotional valence, but not arousal. Our findings further highlight central role of anterior insula in orchestrating proactive cognitive control processes, positioning it at the top of hierarchy for cognitive control.

Multimodal abnormalities of brain structures in adolescents and young adults with major depressive disorder: An activation likelihood estimation meta-analysis

BACKGROUND

Major depressive disorder (MDD) in adolescents and young adults contributes significantly to global morbidity, with inconsistent findings on brain structural changes from structural magnetic resonance imaging studies. Activation likelihood estimation (ALE) offers a method to synthesize these diverse findings and identify consistent brain anomalies.

AIM

To identify consistent brain structural changes in adolescents and young adults with MDD using ALE meta-analysis.

METHODS

We performed a comprehensive literature search in PubMed, Web of Science, Embase, and Chinese National Knowledge Infrastructure databases for neuroimaging studies on MDD among adolescents and young adults published up to November 19, 2023. Two independent researchers performed the study selection, quality assessment, and data extraction. The ALE technique was employed to synthesize findings on localized brain function anomalies in MDD patients, which was supplemented by sensitivity analyses.

RESULTS

Twenty-two studies comprising fourteen diffusion tensor imaging (DTI) studies and eight voxel-based morphometry (VBM) studies, and involving 451 MDD patients and 465 healthy controls (HCs) for DTI and 664 MDD patients and 946 HCs for VBM, were included. DTI-based ALE demonstrated significant reductions in fractional anisotropy (FA) values in the right caudate head, right insula, and right lentiform nucleus putamen in adolescents and young adults with MDD compared to HCs, with no regions exhibiting increased FA values. VBM-based ALE did not demonstrate significant alterations in gray matter volume. Sensitivity analyses highlighted consistent findings in the right caudate head (11 of 14 analyses), right insula (10 of 14 analyses), and right lentiform nucleus putamen (11 of 14 analyses).

CONCLUSION

Structural alterations in the right caudate head, right insula, and right lentiform nucleus putamen in young MDD patients may contribute to its recurrent nature, offering insights for targeted therapies.

Cortical similarities in psychiatric and mood disorders identified in federated VBM analysis via COINSTAC

Structural neuroimaging studies have identified a combination of shared and disorder-specific patterns of gray matter (GM) deficits across psychiatric disorders. Pooling large data allows for examination of a possible common neuroanatomical basis that may identify a certain vulnerability for mental illness. Large-scale collaborative research is already facilitated by data repositories, institutionally supported databases, and data archives. However, these data-sharing methodologies can suffer from significant barriers. Federated approaches augment these approaches by enabling access or more sophisticated, shareable and scaled-up analyses of large-scale data. We examined GM alterations using Collaborative Informatics and Neuroimaging Suite Toolkit for Anonymous Computation, an open-source, decentralized analysis application. Through federated analysis of eight sites, we identified significant overlap in the GM patterns (n = 4,102) of individuals with schizophrenia, major depressive disorder, and autism spectrum disorder. These results show cortical and subcortical regions that may indicate a shared vulnerability to psychiatric disorders.

Interoceptive Processing in Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) are characterized by chronic gastrointestinal symptoms in the absence of overt pathology and affect a significant percentage of the worldwide population. They are commonly accompanied by co-morbid psychiatric symptomatology and are associated with significant suffering and great healthcare services utilization. There is growing evidence that dysregulation of the gut-brain axis and disturbances in the processing of afferent interoceptive signals lie at the heart of these disorders. In this context, the aim of the current review was to detect and critically review original articles focusing on the role of interoception in the pathophysiology of FGIDs. Our search yielded 38 relevant studies. FGID patients displayed increased visceral sensitivity, enhanced attention to gastrointestinal interoceptive cues, and greater emotional arousal when coping with gut-derived sensations. Neuroimaging studies have shown significant structural and functional changes in regions of the interoceptive network, while molecular and genetic studies have revealed significant associations between interoceptive signaling and deficits in excitatory neurotransmission, altered endocrine and immune physiological pathways, and aberrant expression of transient receptor potential channel genes. Finally, there were emerging data suggesting that interoception-based interventions may reduce physical symptoms and improve quality of life and should be integrated into FGID clinical management practices.

White matter and cortical gray matter microstructural abnormalities in new daily persistent headache: a NODDI study

BACKGROUND

New daily persistent headache (NDPH) is a rare primary headache with unclear pathogenesis. Neuroimaging studies of NDPH are limited, and controversy still exists. Diffusion tensor imaging (DTI) is commonly used to study the white matter. However, lacking specificity, the potential pathological mechanisms of white matter microstructural changes remain poorly understood. In addition, the intricacy of gray matter structures impedes the application of the DTI model. Here, we applied an advanced diffusion model of neurite orientation dispersion and density imaging (NODDI) to study the white matter and cortical gray matter microstructure in patients with NDPH.

METHODS

This study assessed brain microstructure, including 27 patients with NDPH, and matched 28 healthy controls (HCs) by NODDI. The differences between the two groups were assessed by tract-based spatial statistics (TBSS) and surface-based analysis (SBA), focusing on the NODDI metrics (neurite density index (NDI), orientation dispersion index (ODI), and isotropic volume fraction (ISOVF)). Furthermore, we performed Pearson's correlation analysis between the NODDI indicators and clinical characteristics.

RESULTS

Compared to HCs, patients with NDPH had a reduction of density and complexity in several fiber tracts. For robust results, the fiber tracts were defined as comprising more than 100 voxels, including bilateral inferior fronto-occipital fasciculus (IFOF), left superior longitudinal fasciculus (SLF) and inferior longitudinal fasciculus (ILF), as well as right corticospinal tract (CST). Moreover, the reduction of neurite density was uncovered in the left superior and middle frontal cortex, left precentral cortex, and right lateral orbitofrontal cortex and insula. There was no correlation between the NODDI metrics of these brain regions and clinical variables or scales of relevance after the Bonferroni correction.

CONCLUSIONS

Our research indicated that neurite loss was detected in both white matter and cortical gray matter of patients with NDPH.

Potential association between suicide risk, aggression, impulsivity, and the somatosensory system

Aggression and impulsivity are linked to suicidal behaviors, but their relationship to the suicidal crisis remains unclear. This magnetoencephalography (MEG) study investigated the link between aggression, impulsivity, and resting-state MEG power and connectivity. Four risk groups were enrolled: high-risk (HR; n = 14), who had a recent suicidal crisis; lower-risk (LR; n = 41), who had a history of suicide attempts but no suicide attempt or ideation in the past year; clinical control (CC; n = 38), who had anxiety/mood disorders but no suicidal history; and minimal risk (MR; n = 28), who had no psychiatric/suicidal history. No difference in resting-state MEG power was observed between the groups. Individuals in the HR group with high self-reported aggression and impulsivity scores had reduced MEG power in regions responsible for sensory/emotion regulation vs. those in the HR group with low scores. The HR group also showed downregulated bidirectional glutamatergic feedback between the precuneus (PRE) and insula (INS) compared to the LR, CC, and MR groups. High self-reported impulsivity was linked to reduced PRE to INS feedback, whereas high risk-taking impulsivity was linked to upregulated INS to postcentral gyrus (PCG) and PCG to INS feedback. These preliminary findings suggest that glutamatergic-mediated sensory and emotion-regulation processes may function as potential suicide risk markers.

Noninvasive neuromodulation of subregions of the human insula differentially affect pain processing and heart-rate variability: a within-subjects pseudo-randomized trial

ABSTRACT

The insula is an intriguing target for pain modulation. Unfortunately, it lies deep to the cortex making spatially specific noninvasive access difficult. Here, we leverage the high spatial resolution and deep penetration depth of low-intensity focused ultrasound (LIFU) to nonsurgically modulate the anterior insula (AI) or posterior insula (PI) in humans for effect on subjective pain ratings, electroencephalographic (EEG) contact heat-evoked potentials, as well as autonomic measures including heart-rate variability (HRV). In a within-subjects, repeated-measures, pseudo-randomized trial design, 23 healthy volunteers received brief noxious heat pain stimuli to the dorsum of their right hand during continuous heart-rate, electrodermal, electrocardiography and EEG recording. Low-intensity focused ultrasound was delivered to the AI (anterior short gyrus), PI (posterior longus gyrus), or under an inert Sham condition. The primary outcome measure was pain rating. Low-intensity focused ultrasound to both AI and PI similarly reduced pain ratings but had differential effects on EEG activity. Low-intensity focused ultrasound to PI affected earlier EEG amplitudes, whereas LIFU to AI affected later EEG amplitudes. Only LIFU to the AI affected HRV as indexed by an increase in SD of N-N intervals and mean HRV low-frequency power. Taken together, LIFU is an effective noninvasive method to individually target subregions of the insula in humans for site-specific effects on brain biomarkers of pain processing and autonomic reactivity that translates to reduced perceived pain to a transient heat stimulus.

Shared and Distinct Neurobiological Bases of Bipolar Disorder and Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Comparative Meta-Analysis of Structural Abnormalities

OBJECTIVE

Pediatric bipolar disorder (PBD) and attention-deficit/hyperactivity disorder (ADHD) frequently co-occur and share dysfunctions in affective and cognitive domains. As the neural substrates underlying their overlapping and dissociable symptomatology have not been well delineated, a meta-analysis of whole-brain voxel-based morphometry studies in PBD and ADHD was conducted.

METHOD

A systematic literature search was performed in PubMed, Web of Science, and Embase. The seed-based d mapping toolbox was used to identify altered clusters of PBD or ADHD and obtain their conjunctive and comparative abnormalities. Suprathreshold patterns were subjected to large-scale network analysis to identify affected brain networks.

RESULTS

The search revealed 10 PBD studies (268 patients) and 32 ADHD studies (1,333 patients). Decreased gray matter volumes in the right insula and anterior cingulate cortex relative to typically developing individuals were conjunctive in PBD and ADHD. Reduced volumes in the right inferior frontal gyrus, left orbitofrontal cortex, and hippocampus were more substantial in PBD, while decreased volumes in the left precentral gyrus, left inferior frontal gyrus, and right superior frontal gyrus were more pronounced in ADHD. Neurodevelopmental effects modulated patterns of the left hippocampus in PBD and those of the left inferior frontal gyrus in ADHD.

CONCLUSION

These findings suggest that PBD and ADHD are characterized by both common and distinct patterns of gray matter volume alterations. Their overlapping abnormalities may represent a transdiagnostic problem of attention and emotion regulation shared by PBD and ADHD, whereas the disorder-differentiating substrates may contribute to the relative differences in cognitive and affective features that define the 2 disorders.

PLAIN LANGUAGE SUMMARY

Pediatric bipolar disorder (BD) and attention-deficit/hyperactivity disorder (ADHD) frequently co-occur, with overlapping changes in emotional and cognitive functioning. This meta-analysis summarizes findings from 10 articles on BD and 32 articles on ADHD to identify similarities and differences in brain structure between youth with BD and youth with ADHD. The authors found that both disorders share decreased gray matter volumes in the right insula and anterior cingulate cortex, which play important roles in emotion processing and attention, respectively. Youth with BD had decreased gray matter volume in the right inferior frontal gyrus, left orbitofrontal gyrus, and left hippocampus, while youth with ADHD had decreased volumes in the left precentral gyrus, left inferior frontal gyrus, and right superior frontal gyrus.

STUDY PREREGISTRATION INFORMATION

Structural Brain Abnormalities of Attention-Deficit/Hyperactivity Disorder and Bipolar Disorder in Children/Adolescents: An Overlapping Meta-analysis; https://osf.io; trg4m.

Reimagining neuroscientific and andragogical principles for dementia care education

This article aims to explore the integration of Louis Cozolino's (2013) andragogical strategies with the tenets of person-centered dementia care practices to enhance dementia care education. The article examines the multiple dimensions of learning in adulthood, highlighting the role of neural plasticity and lifelong brain adaptation in shaping learning and experiential strategies. This in-depth evaluation underscores the significance of tailoring andragogical approaches to the needs of adult learners, who, in this context, are care providers for persons with dementia. This is done through proper understanding of the neurobiological realities and the unique learning needs of adults. Such tailored approaches can be aligned with the brain's adaptive nature by recognizing the intricate interplay of cognitive, emotional, and social dimensions. Highlighting the need for including lessons on the person-centered approach in dementia care education, the paper argues that adult learners - who are essentially part of the dementia care workforce - first need to learn, appreciate, and embrace the approach before applying it in their caregiving practices. This article presents an overarching argument that integration of Cozolino's principles of adult learning with tenets of person-centered dementia care could provide a robust framework for dementia care education.

Deciphering the functional role of insular cortex stratification in trigeminal neuropathic pain

Trigeminal neuropathic pain (TNP) is a major concern in both dentistry and medicine. The progression from normal to chronic TNP through activation of the insular cortex (IC) is thought to involve several neuroplastic changes in multiple brain regions, resulting in distorted pain perception and associated comorbidities. While the functional changes in the insula are recognized contributors to TNP, the intricate mechanisms underlying the involvement of the insula in TNP processing remain subjects of ongoing investigation. Here, we have overviewed the most recent advancements regarding the functional role of IC in regulating TNP alongside insights into the IC's connectivity with other brain regions implicated in trigeminal pain pathways. In addition, the review examines diverse modulation strategies that target the different parts of the IC, thereby suggesting novel diagnostic and therapeutic management of chronic TNP in the future.

Functionality of arousal-regulating brain circuitry at rest predicts human cognitive abilities

Arousal state is regulated by subcortical neuromodulatory nuclei, such as locus coeruleus, which send wide-reaching projections to cortex. Whether higher-order cortical regions have the capacity to recruit neuromodulatory systems to aid cognition is unclear. Here, we hypothesized that select cortical regions activate the arousal system, which, in turn, modulates large-scale brain activity, creating a functional circuit predicting cognitive ability. We utilized the Human Connectome Project 7T functional magnetic resonance imaging dataset (n = 149), acquired at rest with simultaneous eye tracking, along with extensive cognitive assessment for each subject. First, we discovered select frontoparietal cortical regions that drive large-scale spontaneous brain activity specifically via engaging the arousal system. Second, we show that the functionality of the arousal circuit driven by bilateral posterior cingulate cortex (associated with the default mode network) predicts subjects' cognitive abilities. This suggests that a cortical region that is typically associated with self-referential processing supports cognition by regulating the arousal system.

Resting-State EEG Reveals Abnormal Microstate Characteristics of Depression with Insomnia

Previous research revealed various aspects of resting-state EEG for depression and insomnia. However, the EEG characteristics of depressed subjects with insomnia are rarely studied, especially EEG microstates that capture the dynamic activities of the large-scale brain network. To fill these research gaps, the present study collected resting-state EEG data from 32 subclinical depression subjects with insomnia (SDI), 31 subclinical depression subjects without insomnia (SD), and 32 healthy controls (HCs). Four topographic maps were generated from clean EEG data after clustering and rearrangement. Temporal characteristics were obtained for statistical analysis, including cross-group variance analysis (ANOVA) and intra-group correlation analysis. In our study, the global clustering of all individuals in the EEG microstate analysis revealed the four previously discovered categories of microstates (A, B, C, and D). The occurrence of microstate B was lower in SDI than in SD and HC subjects. The correlation analysis showed that the total Pittsburgh Sleep Quality Index (PSQI) score negatively correlated with the occurrence of microstate C in SDI (r = - 0.415, p < 0.05). Conversely, there was a positive correlation between Self-rating Depression Scale (SDS) scores and the duration of microstate C in SD (r = 0.359, p < 0.05). These results indicate that microstates reflect altered large-scale brain network dynamics in subclinical populations. Abnormalities in the visual network corresponding to microstate B are an electrophysiological characteristic of subclinical individuals with symptoms of depressive insomnia. Further investigation is needed for microstate changes related to high arousal and emotional problems in people suffering from depression and insomnia.

Relationship between functional connectivity and weight-gain risk of antipsychotics in schizophrenia

BACKGROUND

The mechanisms by which antipsychotic medications (APs) contribute to obesity in schizophrenia are not well understood. Because AP effects on functional brain connectivity may contribute to weight effects, the current study investigated how AP-associated weight-gain risk relates to functional connectivity in schizophrenia.

METHODS

Fifty-five individuals with schizophrenia (final N = 54) were divided into groups based on previously reported AP weight-gain risk (no APs/low risk [N = 19]; moderate risk [N = 17]; high risk [N = 18]). Resting-state functional magnetic resonance imaging (fMRI) was completed after an overnight fast ("fasted") and post-meal ("fed"). Correlations between AP weight-gain risk and functional connectivity were assessed at the whole-brain level and in reward- and eating-related brain regions (anterior insula, caudate, nucleus accumbens).

RESULTS

When fasted, greater AP weight-gain risk was associated with increased connectivity between thalamus and sensorimotor cortex (pFDR = 0.021). When fed, greater AP weight-gain risk was associated with increased connectivity between left caudate and left precentral/postcentral gyri (pFDR = 0.048) and between right caudate and multiple regions, including the left precentral/postcentral gyri (pFDR = 0.001), intracalcarine/precuneal/cuneal cortices (pFDR < 0.001), and fusiform gyrus (pFDR = 0.008). When fed, greater AP weight-gain risk was also associated with decreased connectivity between right anterior insula and ventromedial prefrontal cortex (pFDR = 0.002).

CONCLUSIONS

APs with higher weight-gain risk were associated with greater connectivity between reward-related regions and sensorimotor regions when fasted, perhaps relating to motor anticipation for consumption. Higher weight-gain risk APs were also associated with increased connectivity between reward, salience, and visual regions when fed, potentially reflecting greater desire for consumption following satiety.

EEG-Based Cortical Alterations in Individuals With Chronic Knee Pain Secondary to Osteoarthritis: A Cross-sectional Investigation

Chronic painful knee osteoarthritis (OA) is a disabling physical health condition. Alterations in brain responses to arthritic changes in the knee may explain persistent pain. This study investigated source localized, resting-state electroencephalography activity and functional connectivity in people with knee OA, compared to healthy controls. Adults aged 44 to 85 years with knee OA (n = 37) and healthy control (n = 39) were recruited. Resting-state electroencephalography was collected for 10 minutes and decomposed into infraslow frequency (ISF) to gamma frequency bands. Standard low-resolution electromagnetic brain tomography statistical nonparametric maps were conducted, current densities of regions of interest were compared between groups and correlation analyses were performed between electroencephalography (EEG) measures and clinical pain and functional outcomes in the knee OA group. Standard low-resolution electromagnetic brain tomography nonparametric maps revealed higher (P = .006) gamma band activity over the right insula (RIns) in the knee OA group. A significant (P < .0001) reduction in ISF band activity at the pregenual anterior cingulate cortex, whereas higher theta, alpha, beta, and gamma band activity at the dorsal anterior cingulate cortex, pregenual anterior cingulate cortex, the somatosensory cortex, and RIns in the knee OA group were identified. ISF activity of the dorsal anterior cingulate cortex was positively correlated with pain measures and psychological distress scores. Theta and alpha activity of RIns were negatively correlated with pain interference. In conclusion, aberrations in infraslow and faster frequency EEG oscillations at sensory discriminative, motivational-affective, and descending inhibitory cortical regions were demonstrated in people with chronic painful knee OA. Moreover, EEG oscillations were correlated with pain and functional outcome measures. PERSPECTIVE: This study confirms alterations in the rsEEG oscillations and its relationship with pain experience in people with knee OA. The study provides potential cortical targets and the EEG frequency bands for neuromodulatory interventions for managing chronic pain experience in knee OA.

Alterations in Brain Morphometric Networks and Their Relationship with Memory Dysfunction in Patients with Type 2 Diabetes Mellitus

Cognitive dysfunction, a significant complication of type 2 diabetes mellitus (T2DM), can potentially manifest even from the early stages of the disease. Despite evidence of global brain atrophy and related cognitive dysfunction in early-stage T2DM patients, specific regions vulnerable to these changes have not yet been identified. The study enrolled patients with T2DM of less than five years' duration and without chronic complications (T2DM group, n=100) and demographically similar healthy controls (control group, n=50). High-resolution T1-weighted magnetic resonance imaging data were subjected to independent component analysis to identify structurally significant components indicative of morphometric networks. Within these networks, the groups' gray matter volumes were compared, and distinctions in memory performance were assessed. In the T2DM group, the relationship between changes in gray matter volume within these networks and declines in memory performance was examined. Among the identified morphometric networks, the T2DM group exhibited reduced gray matter volumes in both the precuneus (Bonferroni-corrected p=0.003) and insular-opercular (Bonferroni-corrected p=0.024) networks relative to the control group. Patients with T2DM demonstrated significantly lower memory performance than the control group (p=0.001). In the T2DM group, reductions in gray matter volume in both the precuneus (r=0.316, p=0.001) and insular-opercular (r=0.199, p=0.047) networks were correlated with diminished memory performance. Our findings indicate that structural alterations in the precuneus and insular-opercular networks, along with memory dysfunction, can manifest within the first 5 years following a diagnosis of T2DM.

Skeletal interoception in osteoarthritis

The interoception maintains proper physiological conditions and metabolic homeostasis by releasing regulatory signals after perceving changes in the internal state of the organism. Among its various forms, skeletal interoception specifically regulates the metabolic homeostasis of bones. Osteoarthritis (OA) is a complex joint disorder involving cartilage, subchondral bone, and synovium. The subchondral bone undergoes continuous remodeling to adapt to dynamic joint loads. Recent findings highlight that skeletal interoception mediated by aberrant mechanical loads contributes to pathological remodeling of the subchondral bone, resulting in subchondral bone sclerosis in OA. The skeletal interoception is also a potential mechanism for chronic synovial inflammation in OA. In this review, we offer a general overview of interoception, specifically skeletal interoception, subchondral bone microenviroment and the aberrant subchondral remedeling. We also discuss the role of skeletal interoception in abnormal subchondral bone remodeling and synovial inflammation in OA, as well as the potential prospects and challenges in exploring novel OA therapies that target skeletal interoception.

Functionality of arousal-regulating brain circuitry at rest predicts human cognitive abilities

Arousal state is regulated by subcortical neuromodulatory nuclei, such as locus coeruleus, which send wide-reaching projections to cortex. Whether higher-order cortical regions have the capacity to recruit neuromodulatory systems to aid cognition is unclear. Here, we hypothesized that select cortical regions activate the arousal system, which in turn modulates large-scale brain activity, creating a functional circuit predicting cognitive ability. We utilized the Human Connectome Project 7T functional magnetic resonance imaging dataset (N=149), acquired at rest with simultaneous eye tracking, along with extensive cognitive assessment for each subject. First, we discovered select frontoparietal cortical regions that drive large-scale spontaneous brain activity specifically via engaging the arousal system. Second, we show that the functionality of the arousal circuit driven by bilateral posterior cingulate cortex (associated with the default mode network) predicts subjects' cognitive abilities. This suggests that a cortical region that is typically associated with self-referential processing supports cognition by regulating the arousal system.

The mindful leader: a review of leadership qualities derived from mindfulness meditation

Mindfulness has been practiced by global leaders and companies as an efficient way to build effective leadership. Because of its popularity, plus the lack of a comprehensive theoretical framework that explains it in a leadership context, the research literature has called for a coherent account of the qualities that is derived by those leaders that practice mindfulness. Here, we aim to answer that call, by clarifying what leadership qualities can develop from practicing mindfulness. We report on a semi-systematic literature review of extant research, covering 19 research articles published between 2000 and 2021, plus other relevant supporting literature from the disciplines of leadership and neuropsychology. Our proposed framework consists of three main qualities of the mindful leader: attention, awareness, and authenticity. We call them the "three pillars of mindful leaders." We also propose that mindfulness meditation must be integrated into our proposed framework, as we are convinced that leaders who hope to benefit from these qualities must integrate a regular mindfulness meditation practice into their daily leadership life.

Comparison of local activation, functional connectivity, and structural connectivity in the N-back task

The N-back task is widely used to investigate working memory. Previous functional magnetic resonance imaging (fMRI) studies have shown that local brain activation depends on the difficulty of the N-back task. Recently, changes in functional connectivity and local activation during a task, such as a single-hand movement task, have been reported to give the distinct information. However, previous studies have not investigated functional connectivity changes in the entire brain during N-back tasks. In this study, we compared alterations in functional connectivity and local activation related to the difficulty of the N-back task. Because structural connectivity has been reported to be associated with local activation, we also investigated the relationship between structural connectivity and accuracy in a N-back task using diffusion tensor imaging (DTI). Changes in functional connectivity depend on the difficulty of the N-back task in a manner different from local activation, and the 2-back task is the best method for investigating working memory. This indicates that local activation and functional connectivity reflect different neuronal events during the N-back task. The top 10 structural connectivities associated with accuracy in the 2-back task were locally activated during the 2-back task. Therefore, structural connectivity as well as fMRI will be useful for predicting the accuracy of the 2-back task.

Altered functional connectivity of brainstem nuclei in new daily persistent headache: Evidence from resting-state functional magnetic resonance imaging

OBJECTIVES

The new daily persistent headache (NDPH) is a rare primary headache disorder. However, the underlying mechanisms of NDPH remain incompletely understood. This study aims to apply seed-based analysis to explore the functional connectivity (FC) of brainstem nuclei in patients with NDPH using resting-state functional magnetic resonance imaging (MRI).

METHODS

The FC analysis from the region of interest (ROI) to whole brain voxels was used to investigate 29 patients with NDPH and 37 well-matched healthy controls (HCs) with 3.0 Tesla MRI. The 76 nuclei in the brainstem atlas were defined as ROIs. Furthermore, we explored the correlations between FC and patients' clinical characteristics and neuropsychological evaluations.

RESULTS

Patients with NDPH exhibited reduced FC in multiple brainstem nuclei compared to HCs (including right inferior medullary reticular formation, right mesencephalic reticular formation, bilateral locus coeruleus, bilateral laterodorsal tegmental nucleus-central gray of the rhombencephalon, median raphe, left medial parabrachial nucleus, periaqueductal gray, and bilateral ventral tegmental area-parabrachial pigmented nucleus complex) and increased FC in periaqueductal gray. No significant correlations were found between the FC of these brain regions and clinical characteristics or neuropsychological evaluations after Bonferroni correction (p > 0.00016).

CONCLUSIONS

Our results demonstrated that patients with NDPH have abnormal FC of brainstem nuclei involved in the perception and regulation of pain and emotions.

Trauma, early life stress, and mindfulness in adulthood

This article is a review that was inspired by recent studies investigating the effects of childhood trauma or early life stress (ELS) and mindfulness in adulthood. One recent study found that some forms of abuse and neglect led to higher scores in several subscales of a self-report measure of mindfulness. The authors concluded that some forms of ELS can help cultivate certain aspects of mindfulness in adulthood. However, and in contrast to this recent finding, much of the extant literature investigating ELS and trauma are linked to emotional dysregulation, alexithymia, and a host of psychopathologies in adulthood which makes the results of this study surprising. Central to the mindfulness literature is cultivating an open, non-reactive, or non-judgment awareness of inner experiences which are important for emotional regulation. In this paper, I review some of the effects of trauma or ELS on critical neural circuits linked to mindfulness, interoception, attachment, and alexithymia which I hope may clarify some of the conflicting findings from this study and throughout the literature and provide additional context and a framework that may inform research investigating these two constructs going forward.