Insular cortex

Role of endocannabinoid neurotransmission in the insular cortex on cardiovascular, autonomic and behavioral responses evoked by acute restraint stress in rats

This study aimed to investigate the role of endocannabinoid mechanisms present within the insular cortex (IC) on cardiovascular, autonomic and anxiogenic-like responses evoked by an acute session of restraint in rats. For this, bilateral guide cannulas directed to the IC were implanted in male Wistar rats for intrabrain microinjection of the selective CB1 receptor antagonist AM251, the selective TRPV1 receptor antagonist capsazepine, the fatty acid amide hydrolase (FAAH) inhibitor URB597 or the monoacylglycerol lipase (MAGL) inhibitor JZL184. The effects of pharmacological treatments were evaluated on restraint-evoked increases in blood pressure and heart rate, sympathetically-mediated cutaneous vasoconstriction and in delayed anxiogenic-like effect assessed 24h after stress exposure in the elevated plus maze (EPM) and open field (OF). We observed that acute restraint stress decreased the exploration of both EPM open arms and OF center region in animals treated with vehicle into the IC, thus indicating an anxiogenic-like effect. Inhibition of MAGL within the IC evoked by local treatment with JZL184 avoided the restraint-evoked anxiogenic effect. IC treatment with JZL184 also attenuated the tachycardia during restraint. The other pharmacological treatments did not modify the cardiovascular, autonomic and behavioral responses evoked by restraint. Taken together, these findings suggest that endocannabinoid neurotransmission in the IC, potentially acting through the endocannabinoid 2-arachidonoylglycerol, plays an inhibitory role in both tachycardia and anxiogenic-like effect evoked by stressful events.

The neural basis of affective empathy: What is known from rodents

Empathy is the cornerstone of social interactions between conspecies for human beings and other social animals. Human beings with empathy defects might either suffer unpleasant or failed social interactions as ASD patients, or even display antisocial behaviors. To find efficient cure for empathy defects, first of all, the neural mechanisms underpinning various empathy behaviors should be well studied and understood. And the research in the field of affective empathy thrives fast in recent years. It is necessary to review the important contributions in this field, especially for understanding the delicate neural mechanisms of diverse forms of affective empathy. Here, we have summarized the characteristics of various types of affective empathy. We also discuss the distinctions between empathy for pain and fear, as well as instinctive and experienced empathy. Our analysis further highlights the findings in the complex neural mechanisms and potential brain regions underlying different affective empathy behaviors. Above all, this work is expected to help enhance our comprehension of behavioral dynamics and neural basis of affective empathy along with its role in emotional regulation and social behavior.

Neural correlates of psychotherapy in mental disorders: A meta-analysis of longitudinal resting-state fMRI studies

BACKGROUND

Psychotherapy is a crucial approach in the treatment of mental disorders. However, how psychotherapy modulate spontaneous brain activity and finally take therapeutic effects remain unknown. Among countless number of analytic methods of resting-state functional magnetic resonance imaging (rs-fMRI), Regional Homogeneity (ReHo), Degree Centrality (DC), and Amplitude of Low Frequency Fluctuation (ALFF), are commonly used voxel-wise whole-brain (VWWB) metrics, and these studies could be used for coordinate-based meta-analysis. In order to reveal the underlying neural mechanisms of psychotherapy in patients with mental disorders, serving for future precise targeting intervention, we conducted a systematic review and meta-analysis based on rs-fMRI studies at VWWB level.

MATERIAL AND METHODS

A systematic literature search was conducted in PubMed, PsycINFO, and Web of Science following PRISMA criteria (registration number CRD42023432388) to investigate the differences between pre- and post-psychotherapy. To investigate whether changes in spontaneous brain activity differ across different metrics, distinct psychotherapy approaches or specific patient populations, subgroup analyses were performed.

RESULTS

Nine studies involving a total of 192 patients were included. We observed a significant decrease in spontaneous activity within the left insular after treatment with psychotherapy. Moreover, the subgroup analysis revealed significantly decreased ReHo in the right inferior frontal gyrus.

CONCLUSIONS

The current study indicates that the clinical efficacy of psychotherapy may be modulated by insular and right inferior frontal gyrus through neurological perspective. This contributes to our understanding of the neurobiological mechanisms of psychotherapy and provides valuable insights into improving precise targeting interventions for individuals with mental disorders.

Structural brain pattern abnormalities in tinnitus with and without hearing loss

OBJECTIVE

Subjective tinnitus often coexists with hearing loss, and they share common pathophysiological mechanisms. This comorbidity induces whole-brain gray matter volume (GMV) alterations, manifesting as distributed structural changes in neural networks rather than isolated regional modifications. Multivariate analysis of structural brain patterns is therefore essential to differentiate their underlying mechanisms.

METHODS

Fifty tinnitus patients and 50 age-/gender-matched controls underwent structural MRI and audiometry. Patients were stratified by hearing level into 22 with hearing loss (T+HL) and 28 without (T-HL). To investigate structural brain patterns specific to tinnitus and hearing loss, Source-Based Morphometry (SBM), a multivariate analytical approach based on Independent Component Analysis (ICA), was applied to identify covarying patterns of GMV. The associations between these structural covariance patterns and clinical characteristics were examined using Spearman's correlation analysis.

RESULTS

Our results showed that in T-HL patients, structural abnormalities in the medial prefrontal cortex, precuneus, and auditory cortex were negatively correlated with tinnitus distress. In contrast, in T+HL patients, abnormalities in the insular structural brain pattern were negatively associated with depressive symptoms.

CONCLUSIONS

Our findings revealed that tinnitus-related structural brain patterns involve regions such as the middle frontal gyrus, supplementary motor area (SMA), and anterior cingulate cortex (ACC), with these changes negatively correlating with tinnitus distress, suggesting adaptive mechanisms in tinnitus perception. Moreover, the structural brain pattern involving the insula, putamen, and superior temporal gyrus appears to be primarily driven by hearing loss. These findings support audiometric-based subgrouping in tinnitus management.

Common neural correlates of chronic pain - A systematic review and meta-analysis of resting-state fMRI studies

Maladaptive brain plasticity has been reported in chronic pain (CP) conditions, though it remains unclear if there are common alterations across pathologies. Therefore, we systematically synthesized literature comparing resting-state functional magnetic resonance imaging (rs-fMRI) in CP patients and healthy controls (HC), and meta-analyzed data whenever applicable. Separate meta-analyses were performed for each method - (fractional) amplitude of low-frequency fluctuations (fALFF, ALFF), regional homogeneity (ReHo), seed-based connectivity (according to the seed) and independent component analysis (according to the network). In qualitative synthesis, sensory-discriminative pain processing - thalamus, insula, temporal and sensory cortices - and cognitive and emotional processing - cingulate, prefrontal and parietal cortices and precuneus - regions concentrated CP/HC differences. Meta-analyses revealed decreased ALFF and increased ReHo in the precuneus, increased fALFF in the left posterior insula and disrupted within- and cross-network connectivity of default mode network (DMN) nodes, as well as altered connectivity in top-down pain modulation pathways. Specifically, it showed decreased anterior and increased posterior components' representation within DMN, enhanced connectivity between the medial prefrontal cortex (mPFC, part of the DMN) and anterior insula (part of the salience network), and decreased mPFC connectivity with the periaqueductal gray matter (PAG). Collectively, results suggest that CP disrupts the natural functional organization of the brain, particularly impacting DMN nodes (mPFC and precuneus), insula and top-town pain modulation circuits.

Exploring neuroanatomy and neuropsychology in digital financial decision-making: betrayal aversion and risk behavior

Detecting the factors associated with financial decision-making is an unresolved challenge when trying to predict digital financial behavior. This paper reports experimental results on both neuropsychological and neuronal correlates of risk-taking and betrayal aversion among 121 healthy participants (Xage=21.7; SD = 2.8). A questionnaire on financial habits was administered, followed by neuropsychological tests and a magnetic resonance imaging session while participants viewed videos depicting both traditional and digital economic transactions. Participants also completed a computerized version of trust and risk games. Results reveal that Sensitivity to Punishment and Negative Urgency significantly predict risk behavior. High betrayal aversion was associated with greater sensitivity to punishment as well as lower volume in temporal areas. Cluster analysis identified two distinct psychological profiles based on betrayal aversion scores, highlighting differences in sensitivity to punishment, negative urgency, positive urgency, and trust game score. Furthermore, cortical thickness comparisons revealed differences between low and high-aversion groups, particularly in the temporal, parietal, and insular areas. White matter analysis indicated less integration in specific tracts among individuals with high betrayal aversion. These findings suggest the influence of neuropsychological factors on the adoption of risky financial behaviors and emotional response to betrayal.

The brain-heart axis: integrative cooperation of neural, mechanical and biochemical pathways

The neural and cardiovascular systems are pivotal in regulating human physiological, cognitive and emotional states, constantly interacting through anatomical and functional connections referred to as the brain-heart axis. When this axis is dysfunctional, neurological conditions can lead to cardiovascular disorders and, conversely, cardiovascular dysfunction can substantially affect brain health. However, the mechanisms and fundamental physiological components of the brain-heart axis remain largely unknown. In this Review, we elucidate these components and identify three primary pathways: neural, mechanical and biochemical. The neural pathway involves the interaction between the autonomic nervous system and the central autonomic network in the brain. The mechanical pathway involves mechanoreceptors, particularly those expressing mechanosensitive Piezo protein channels, which relay crucial information about blood pressure through peripheral and cerebrovascular connections. The biochemical pathway comprises many endogenous compounds that are important mediators of neural and cardiovascular function. This multisystem perspective calls for the development of integrative approaches, leading to new clinical specialties in neurocardiology.

Magnetic resonance imaging of regional gray matter volume in persons who died by suicide

In vivo neuroimaging research in suicide attempters has shown alterations in frontal system brain regions subserving emotional regulation, motivation, and self-perception; however, data from living individuals is limited in clarifying risk for suicide death. Postmortem neuroimaging provides an approach to study the brain in persons who died by suicide. Here, whole brain voxel-based analyses of magnetic resonance imaging gray matter volume measures were performed comparing persons confirmed by forensic investigation to have died by suicide (n = 24), versus other causes (n = 24), in a univariate model covarying for age and total brain volume; all subjects were scanned within 24 hours after death. Consistent with the hypothesis that persons who died by suicide would show lower gray matter volume in frontal system brain regions, this study of suicides showed lower gray matter volume in ventral frontal and its major connection sites including insula, striatum, and amygdala.

Painful Todd's: Post-ictal painful hemiparesis as an identifier of insular epilepsy

The insula can generate seizures which mimic frontal, temporal and parietal epilepsies making electroclinical localization difficult. We report the case of a twenty-one-year-old woman who presented with seizure semiology of a left-sided painful somatosensory aura, progressing to bilateral tonic posturing and complex manual automatisms. She described a painful sensation and weakness affecting her left side following the offset of a seizure, with the pain consistenly outlasting the weakness. This would last from hours to days depending on the severity and duration of the seizure. Stereo-electroencephalography (SEEG) demonstrated seizure onset in the limen of the right insula. Extra-operative stimulation of the insula reproduced the clinical symptoms. She underwent radiofrequency thermocoagulation (RFTC) which has resulted in a significant reduction in seizure frequency. This case report describes a lateralized painful Todd's phenomenon as a feature of insular epilepsy confirmed by SEEG and extra-operative stimulation.

Exploring cognitive functions and brain structure in Hereditary Transthyretin amyloidosis using brain MRI and neuropsychological assessment

BACKGROUND

Central nervous system symptoms, such as cognitive dysfunction, have been reported in Hereditary Transthyretin Amyloidosis (ATTRv). However, there is a lack of neuroimaging studies investigating structural alterations in the brain related to cognition in ATTRv amyloidosis. This study aimed to investigate cognition and cortical morphology in a cohort of ATTRv patients.

METHODS

29 ATTRv patients and 26 healthy controls completed neuropsychological assessment. 21 of these patients underwent 3T brain MRI, and 23 healthy subjects constituted the control group for MRI. Cortical measures of volume, thickness, fractional anisotropy (FA), and mean diffusivity (MD) were obtained for both groups. Correlation analyses between brain and cognitive measurements were performed.

RESULTS

Patients displayed worse performance than controls in executive functions, verbal and visual memory, visuospatial domains, and language tests. Our study indicated cortical thinning in ATTRv patients in the temporal, occipital, frontal, and parietal areas. The inferior temporal gyrus correlated with verbal memory. Insula and, pars opercularis correlated with both verbal memory and executive function.

CONCLUSIONS

Cortical thickness in the inferior temporal gyrus, pars opercularis, and insula were linked to memory and executive function. We observed no correlations between cortical volume measures and cognition. Further investigations are imperative to confirm these findings across different populations.

Cognitive and clinical dimensions of structural and functional insula alterations in patients with depression: a resting-state fMRI study

Aim: Depression is characterized by pervasive cognitive and emotional disturbances, yet the neural mechanisms underlying these deficits remain incompletely understood. Method: This study utilized multimodal neuroimaging, including resting-state functional MRI and structural T1-weighted imaging, alongside the MATRICS Consensus Cognitive Battery (MCCB) and the Hamilton Depression Rating Scale (HAMD), to delineate the structural and functional alterations in the insula in first-episode, medication-naïve patients with depression. Result: Compared to matched healthy controls, patients with depression exhibited significant reductions in gray matter density in the left insula, which were robustly associated with impairments in reasoning and problem-solving abilities. Mediation analyses revealed that insular gray matter density mediated the relationship between depressive symptom severity and cognitive deficits, emphasizing the insula's critical role in linking emotional and cognitive dysfunctions. Furthermore, functional connectivity analyses identified disrupted insula-medial prefrontal cortex circuits, highlighting their contribution to the pathophysiology of depression. Conclusion: These findings underscore the insula's dual role as a structural and functional hub in depression, advancing our understanding of the neural substrates of cognitive dysfunction and informing potential targets for intervention.

Association of sarcopenia with regional brain atrophy and white matter lesions in a general older population: the Hisayama Study

Sarcopenia has been reported to be associated with cognitive decline and the risk of dementia. However, few studies have addressed the association between sarcopenia and brain morphological changes in the general population. A total of 1373 community-dwelling participants aged ≥ 65 years underwent brain MRI. Sarcopenia was defined based on the Asian Working Group for Sarcopenia's criteria. The pattern of regional gray matter volume loss associated with sarcopenia were assessed using a voxel-based morphometry (VBM) analysis. Regional brain volumes, intracranial volumes (ICV), and white matter lesions volumes (WMLV) were also measured using FreeSurfer. An analysis of covariance was used to examine the associations of sarcopenia with regional brain volumes in proportion to ICV. Of the participants, 112 had sarcopenia. The participants with sarcopenia had significantly lower total brain volume/ICV and total gray matter volume/ICV and higher WMLV/ICV than those without sarcopenia after adjusting for confounders. In VBM, sarcopenia was associated with lower gray matter volume in the frontal lobe, insula, cingulate gyrus, hippocampus, amygdala, and basal ganglia. Using FreeSurfer, we confirmed that the participants with sarcopenia had significantly lower frontal, insular, cingulate, and hippocampal volumes than those without sarcopenia. The current study showed that participants with sarcopenia had significantly lower volume in the frontal lobe, insula, cingulate, and hippocampus and higher WMLV than participants without sarcopenia. As these brain regions are likely to play an important role in cognitive function, these changes may suggest a shared underlying mechanism for the progression of sarcopenia and cognitive decline.

Differences in cerebral spontaneous neural activity correlate with gene-specific transcriptional signatures in primary angle-closure glaucoma

AIMS

This study was aimed to investigate frequency-specific LFO changes and their correlation with gene pathways in PACG using transcriptome-neuroimaging analysis.

METHODS

Resting-state fMRI (Rs-fMRI) data were acquired from individuals with PACG and healthy controls for evaluating the amplitude of low-frequency oscillations (ALFF) across different frequency bands such as the full band, slow-4 band, and slow-5 band. Transcriptome analysis integrated information from the Allen Human Brain Atlas (AHBA) through gene set enrichment analysis, protein-protein interaction network construction, and specific expression analysis, aiming to clarify the link between ALFF patterns and gene expression profiles in PACG. Statistical analyses, including one-sample t-tests and two-sample t-tests, were used to assess ALFF differences between groups, while partial least squares (PLS) regression was applied to explore the associations between ALFF and transcriptome data.

RESULTS

This study identifies significant variations in ALFF values in PACG patients, observed consistently across multiple frequency bands, including slow-4 and slow-5. Enrichment analysis indicates that these genes are primarily involved in cellular components such as the cytosol and cytoplasm, molecular functions like protein binding, and key pathways, including metabolic and circadian rhythms, epithelial signaling in Helicobacter pylori infection, and glutathione metabolism. Protein-protein interaction (PPI) analysis further underscores the role of PACG-related genes in forming a functional network, highlighting hub genes critical for various biological processes.

CONCLUSION

This study establishes a connection between the molecular mechanisms of PACG and alterations in brain function and gene expression, providing valuable perspectives on the fundamental processes impacting low-frequency oscillations in PACG.

Abdominal pain as a novel manifestation in children with PCDH19-related epilepsy: A case report

RATIONALE

PCDH19-related epilepsy manifested various clinical features, including febrile epilepsy, with or without intellectual disability, and psych-behavioral disorders. However, there are few studies demonstrating abdominal pain as the first symptom.

PATIENT CONCERNS

A 3-year-old Chinese girl presented with clustered seizures of fever sensitivity accompanied by abdominal pain.

DIAGNOSES

After ultrasonography ruled out abdominal organic lesions, electroencephalographic (EEG) identified abdominal pain was a seizure feature. Trio whole-exome sequence demonstrated a de novo and heterozygous PCDH19 missense mutation (NM_001184880: c.824A>G, P.Y275C), which was confirmed by Sanger sequence. The final diagnosis were "PCDH19-related epilepsy; abdominal pain."

INTERVENTIONS

At first, she was treated ineffectively by levetiracetam and valproate. Finally, she was provided with topiramate (TPM).

OUTCOMES

The patient had gained seizure-free, and the follow-up EEG discharges were reduced.

LESSONS

Abdominal pain is a rare autonomic symptom in the setting of seizures. This report describes abdominal pain as a novel manifestation of PCDH19-related epilepsy and might expand its phenotypes spectrum. It also alerts us to perceive the abdominal pain characterized by seizures and early conduct EEG examination to clarify the nature of abdominal pain.

An Island of Reil excitation: Mapping glutamatergic (vGlut1+ and vGlut2+) connections in the medial insular cortex

The insular cortex is a multifunctional and richly connected region of the cerebral cortex, critical in the neural integration of external stimuli and internal signals. Well-served for this role by a large network of afferent and efferent connections, the mouse insula can be simplified into an anterior, medial and posterior portion. Here we focus on the medial subregion, a once over-looked area that has gained recent attention for its involvement in an array of behaviours. Although the connections of medial insular cortex neurons have been previously identified, their precise glutamatergic phenotype remains undefined (typically defined by the presence of the subtype of vesicular glutamate transporters). Hence, we combined Cre knock-in mouse lines and adeno-associated viral tracing to distinguish between the expression of the two major vesicular glutamate transporters, type 1 (vGlut1) and 2 (vGlut2), in the subregion's neuronal inputs and outputs. Our results determined that the medial insula has extensive glutamatergic efferents expressing both vGlut1 and vGlut2 throughout the neuraxis. In contrast, a more conservative number of glutamatergic inputs were observed, with exclusively vGlut2+ projections received from hypothalamic and thalamic regions. Taken together, we demonstrate that vGlut1- and vGlut2-expressing networks of this insular subdivision have distinct connectivity patterns, including a greater abundance of vGlut1+ fibres innervating hypothalamic regions and the extended amygdala. These findings provide insight into the distinct chemo-architecture of this region, which may facilitate further investigation into the role of the medial insula in complex behaviour.

Genetic risk factors underlying white matter hyperintensities and cortical atrophy

White matter hyperintensities index structural abnormalities in the cerebral white matter, including axonal damage. The latter may promote atrophy of the cerebral cortex, a key feature of dementia. Here, we report a study of 51,065 individuals from 10 cohorts demonstrating that higher white matter hyperintensity volume associates with lower cortical thickness. The meta-GWAS of white matter hyperintensities-associated cortical 'atrophy' identifies 20 genome-wide significant loci, and enrichment in genes specific to vascular cell types, astrocytes, and oligodendrocytes. White matter hyperintensities-associated cortical 'atrophy' showed positive genetic correlations with vascular-risk traits and plasma biomarkers of neurodegeneration, and negative genetic correlations with cognitive functioning. 15 of the 20 loci regulated the expression of 54 genes in the cerebral cortex that, together with their co-expressed genes, were enriched in biological processes of axonal cytoskeleton and intracellular transport. The white matter hyperintensities-cortical thickness associations were most pronounced in cortical regions with higher expression of genes specific to excitatory neurons with long-range axons traversing through the white matter. The meta-GWAS-based polygenic risk score predicts vascular and all-cause dementia in an independent sample of 500,348 individuals. Thus, the genetics of white matter hyperintensities-related cortical atrophy involves vascular and neuronal processes and increases dementia risk.

Longitudinal evidence for a mutually reinforcing relationship between white matter hyperintensities and cortical thickness in cognitively unimpaired older adults

BACKGROUND

For over three decades, the concomitance of cortical neurodegeneration and white matter hyperintensities (WMH) has sparked discussions about their coupled temporal dynamics. Longitudinal studies supporting this hypothesis nonetheless remain scarce.

METHODS

We applied global and regional bivariate latent growth curve modelling to determine the extent to which WMH and cortical thickness were interrelated over a four-year period. For this purpose, we leveraged longitudinal MRI data from 451 cognitively unimpaired participants (DELCODE; median age 69.71 [IQR 65.51, 75.50] years; 52.32% female). Participants underwent MRI sessions annually over a four-year period (1815 sessions in total, with roughly four MRI sessions per participant). We adjusted all models for demographics and cardiovascular risk.

RESULTS

Our findings were three-fold. First, larger WMH volumes were linked to lower cortical thickness (σ = -0.165, SE = 0.047, Z = -3.515, P < 0.001). Second, individuals with higher WMH volumes experienced more rapid cortical thinning (σ = -0.226, SE = 0.093, Z = -2.443, P = 0.007), particularly in temporal, cingulate, and insular regions. Similarly, those with lower initial cortical thickness had faster WMH progression (σ = -0.141, SE = 0.060, Z = -2.336, P = 0.009), with this effect being most pronounced in temporal, cingulate, and insular cortices. Third, faster WMH progression was associated with accelerated cortical thinning (σ = -0.239, SE = 0.139, Z = -1.710, P = 0.044), particularly in frontal, occipital, and insular cortical regions.

CONCLUSIONS

Our study suggests that cortical thinning and WMH progression could be mutually reinforcing rather than parallel, unrelated processes, which become entangled before cognitive deficits are detectable.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS00007966, 04/05/2015).

Surgical treatment of long-term epilepsy-associated tumors guided by stereoelectroencephalography

PURPOSE

Accurate detection and resection of the epileptogenic zone (EZ) in patients with long-term epilepsy-associated tumors (LEATs) are significantly correlated with favorable seizure prognosis. However, the relationship between tumors and the EZ remains unknown. This study aimed to evaluate the spatial relationship between LEATs and the EZ, as well as the electrophysiological features of LEATs.

METHODS

We retrospectively studied five patients with LEATs who underwent deep electrode implantation and EZ resection in the hospital. The clinical characteristics, surgical outcomes, localizing features and intracranial SEEG results were reviewed.

RESULTS

One female and four males (mean age: 25.2 years; median age: 24 years; range: 13-45 years) were included in the study. Five-to-eleven electrodes (mean: 8.4) were implanted per patient. The EZ was located in the tumor and nearby cortex in three cases and in the tumor and distant areas in two cases. Pathological examination revealed ganglioglioma in four cases, two of which were associated with hippocampal sclerosis, and the other case showed a multinodular and vacuolating neuronal tumor with gliosis. All patients were seizure-free for at least 24 months postoperatively.

CONCLUSIONS

SEEG provides valuable insights into the electrophysiological mechanisms of LEATs. The EZ often contains brain tissue around the tumor. However, only a few cases, particularly those with temporoparietal occipital (TPO) area involvement, a long history of epilepsy and other abnormalities on MRI, such as hippocampal sclerosis and focal cortical dysplasia, may include distant areas.

Precision Network Modeling of Transcranial Magnetic Stimulation Across Individuals Suggests Therapeutic Targets and Potential for Improvement

Higher-order cognitive and affective functions are supported by large-scale networks in the brain. Dysfunction in different networks is proposed to associate with distinct symptoms in neuropsychiatric disorders. However, the specific networks targeted by current clinical transcranial magnetic stimulation (TMS) approaches are unclear. While standard-of-care TMS relies on scalp-based landmarks, recent FDA-approved TMS protocols use individualized functional connectivity with the subgenual anterior cingulate cortex (sgACC) to optimize TMS targeting. Leveraging previous work on precision network estimation and recent advances in network-level TMS targeting, we demonstrate that clinical TMS approaches target different functional networks between individuals. Homotopic scalp positions (left F3 and right F4) target different networks within and across individuals, and right F4 generally favors a right-lateralized control network. We also modeled the impact of targeting the dorsolateral prefrontal cortex (dlPFC) zone anticorrelated with the sgACC and found that the individual-specific anticorrelated region variably targets a network coupled to reward circuitry. Combining individualized, precision network mapping and electric field (E-field) modeling, we further illustrate how modeling can be deployed to prospectively target distinct closely localized association networks in the dlPFC with meaningful spatial selectivity and E-field intensity and retrospectively assess network engagement. Critically, we demonstrate the feasibility and reliability of this approach in an independent cohort of participants (including those with Major Depressive Disorder) who underwent repeated sessions of TMS to distinct networks, with precise targeting derived from a low-burden single session of data. Lastly, our findings emphasize differences between selectivity and maximal intensity, highlighting the need to consider both metrics in precision TMS efforts.

[Insular lobe epilepsy. Part 1: semiology]

The insula is often referred to as "the fifth lobe" of the brain, and its accessibility used to be very limited due to the deep location under the opercula as well as the sylvian vasculature. It was not until the availability of modern stereo-electroencephalography (SEEG) technique that the intracranial electrodes could be safely and chronically implanted within the insula, thereby enabling anatomo-electro-clinical correlations in seizures of this deep origin. Since the first report of SEEG-recorded insular seizures in late 1990s, the knowledge of insular lobe epilepsy (ILE) has rapidly expanded. Being on the frontline for the diagnosis and management of epilepsy, neurologists should have a precise understanding of ILE to differentiate it from epilepsies of other lobes or non-epileptic conditions. Owing to the multimodal nature and rich anatomo-functional connections of the insula, ILE has a wide range of clinical presentations. The following symptoms should heighten the suspicion of ILE: somatosensory symptoms involving a large/bilateral cutaneous territory or taking on thermal/painful character, and cervico-laryngeal discomfort. The latter ranges from slight dyspnea to a strong sensation of strangulation (laryngeal constriction). Other symptoms include epigastric discomfort/nausea, hypersalivation, auditory, vestibular, gustatory, and aphasic symptoms. However, most of these insulo-opercular symptoms can easily be masked by those of extra-insular seizure propagation. Indeed, sleep-related hyperkinetic (hypermotor) epilepsy (SHE) is a common clinical presentation of ILE, which shows predominant hyperkinetic and/or tonic-dystonic features that are often indistinguishable from those of fronto-mesial seizures. Subtle objective signs, such as constrictive throat noise (i.e., laryngeal constriction) or aversive behavior (e.g., facial grimacing suggesting pain), are often the sole clue in diagnosing insular SHE. Insular-origin seizures should also be considered in temporal-like seizures without frank anatomo-electro-clinical correlations. All in all, ILE is not the epilepsy of an isolated island but rather of a crucial hub involved in the multifaceted roles of the brain.

Data-driven analysis of whole-brain intrinsic connectivity in patients with chronic low back pain undergoing osteopathic manipulative treatment

BACKGROUND

Chronic Low Back Pain (cLBP) poses a significant health challenge, leading to functional disability and reduced quality of life. Osteopathic Manipulative Treatment (OMT) is emerging as a therapeutic option for cLBP, but the brain mechanisms underlying its analgesic effect remain unclear.

MATERIALS AND METHODS

Thirty cLBP patients were randomly exposed to either four weekly sessions of OMT (N=16) or Sham treatment (N=14). Resting-state Magnetic Resonance Imaging (rs-MRI) scans and pain perception questionnaires were collected before and after treatment. A voxel-wise, rs-fMRI data-driven analysis was conducted to identify changes in the intrinsic functional connectivity across the whole brain that were associated with the OMT. Spearman's correlations were used to test for the association between changes in intrinsic connectivity and individual reports of pain perception.

RESULTS

Compared to the Sham group, participants who received OMT showed significant alterations in the functional connectivity of several regions belonging to the pain matrix. Specifically, OMT was associated with decreased connectivity of a parietal cluster that includes the somatosensory cortex and an increase of connectivity of the right anterior insula and ventral and dorsal anterolateral prefrontal areas. Crucially, the change in connectivity strength observed in the ventral anterolateral prefrontal cortex, a putative region of the affective-reappraisive layer of the pain matrix, correlates with the reduction in pain perception caused by the OMT.

CONCLUSIONS

This study offers insights into the brain mechanisms underlying the analgesic effect of OMT. Our findings support a link between OMT-driven functional cortical architecture alterations and improved clinical outcomes.

The amplitude of low-frequency fluctuations is correlated with birth trauma in patients with postpartum post-traumatic stress disorder

Postpartum post-traumatic stress disorder (PP-PTSD) is a severe mental disorder worldwide. In recent years, some studies have reported that PP-PTSD stems from birth trauma. The present study was dedicated in finding ways to predict the occurrence of emergency caesarean section (ECS), trying to analyze the methods to reduce incidence of PP-PTSD on this basis, further exploring the neuroimaging changes in PP-PTSD. A total of 245 primiparas with intention of vaginal delivery were recruited. The internal tocodynamometry measurement was performed during labor for all mothers, and respectively taken at 3-5 cm, 5-8 cm, and 8-10 cm of cervical dilation. The receiver operating characteristic (ROC) curve and Binary logistic regression analyses were also performed to identify fetal head descending thrust that might help in the prediction of ECS. Resting-state magnetic resonance imaging (MRI) was performed on 26 patients diagnosed with PP-PTSD of 245 mothers, the amplitude of low-frequency fluctuations (ALFF) technology was used to observe the spontaneous neural activity of all PP-PTSD patients and correlation analyses were performed. We found that the natural delivery rate of mothers with fetal head descending thrust <16.29 N (5-8 cm), 26.36 N (8-10 cm) were respectively lower than other mothers with fetal head descending thrust ≥16.29 N (5-8 cm), 26.36 N (8-10 cm) (P < 0.05). The ROC curve analysis showed that the area under the receiver operating characteristic curve (AUC) value of thrust (5-8 cm) was 0.896 (95% CI: 0.854-0.938, p < 0.001), AUC of thrust(8-10 cm) was 0.786 (95% CI: 0.714-0.858, p < 0.001), which showed strong potential for predicting ECS. In addition, the Binary logistic regression analysis showed thrust (5-8 cm) and thrust (8-10 cm) were independent correlates of ECS. The resting-state functional magnetic resonance imaging (rs-fMRI) results indicated that PP-PTSD group showed decreased ALFF in the bilateral insula cortex (IC), right anterior cingulate cortex (ACC), and left midcingulate cortex (MCC) compared with healthy postpartum women (HPW) (false discovery rate (FDR) correction q-value < 0.05). The ALFF value of the right ACC was positively correlated with the Perinatal Post-traumatic stress disorder Questionnaire (PPQ) score (r = 0.4046 p = 0.0403) and Posttraumatic Stress Disorder Checklist-Civilian Version (PCL-C) score (r = 0.3909 p = 0.0483). The internal tocodynamometry measurement can serve as a predictive tool for ECS, on this basis, the implementation of effective emotional support may help to reduce the incidence of PP-PTSD. Besides, this study has verified the presence of altered ALFF in the brain regions of PP-PTSD patients, mainly involving the bilateral IC, right ACC, and left MCC, that might be associated with emotion, cognition, and memory disorders functions in PP-PTSD patients.

Low-intensity focused ultrasound to the posterior insula reduces temporal summation of pain

BACKGROUND

The insula and dorsal anterior cingulate cortex (dACC) are core brain regions involved in pain processing and central sensitization, a shared mechanism across various chronic pain conditions. Methods to modulate these regions may serve to reduce central sensitization, though it is unclear which target may be most efficacious for different measures of central sensitization.

OBJECTIVE/HYPOTHESIS

Investigate the effect of low-intensity focused ultrasound (LIFU) to the anterior insula (AI), posterior insula (PI), or dACC on conditioned pain modulation (CPM) and temporal summation of pain (TSP).

METHODS

N = 16 volunteers underwent TSP and CPM pain tasks pre/post a 10 min LIFU intervention to either the AI, PI, dACC or Sham stimulation. Pain ratings were collected pre/post LIFU.

RESULTS

Only LIFU to the PI significantly attenuated pain ratings during the TSP protocol. No effects were found for the CPM task for any of the LIFU targets. LIFU pressure modulated group means but did not affect overall group differences.

CONCLUSIONS

LIFU to the PI reduced temporal summation of pain. This may, in part, be due to dosing (pressure) of LIFU. Inhibition of the PI with LIFU may be a future potential therapy in chronic pain populations demonstrating central sensitization. The minimal effective dose of LIFU for efficacious neuromodulation will help to translate LIFU for therapeutic options.

Development of a prediction model for cognitive impairment of sarcopenia using multimodal neuroimaging in non-demented older adults

INTRODUCTION

Despite prior research on the association between sarcopenia and cognitive impairment in the elderly, a comprehensive model that integrates various brain pathologies is still lacking.

METHODS

We used data from 528 non-demented older adults with or without sarcopenia in the Catholic Aging Brain Imaging (CABI) database, containing magnetic resonance imaging scans, positron emission tomography scans, and clinical data. We also measured three key components of sarcopenia: skeletal muscle index (SMI), hand grip strength (HGS), and the five times sit-to-stand test (5STS).

RESULTS

All components of sarcopenia were significantly correlated with global cognitive function, but cortical thickness and amyloid-beta (Aβ) retention had distinctive relationships with each measure. In the path model, brain atrophy resulting in cognitive impairment was mediated by Aβ retention for SMI and periventricular white matter hyperintensity for HGS, but directly affected by the 5STS.

DISCUSSION

Treatments targeting each sub-domain of sarcopenia should be considered to prevent cognitive decline.

HIGHLIGHTS

We identified distinct impacts of three sarcopenia measures on brain structure and Aβ. Muscle mass is mainly associated with Aβ and has an influence on the brain atrophy. Muscle strength linked with periventricular WMH and brain atrophy. Muscle function associated with cortical thinning in specific brain regions. Interventions on sarcopenia may be important to ease cognitive decline in the elderly.

Exploring potential neuroimaging biomarkers for the response to non-steroidal anti-inflammatory drugs in episodic migraine

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are considered first-line medications for acute migraine attacks. However, the response exhibits considerable variability among individuals. Thus, this study aimed to explore a machine learning model based on the percentage of amplitude oscillations (PerAF) and gray matter volume (GMV) to predict the response to NSAIDs in migraine treatment.

METHODS

Propensity score matching was adopted to match patients having migraine with response and nonresponse to NSAIDs, ensuring consistency in clinical characteristics and migraine-related features. Multimodal magnetic resonance imaging was employed to extract PerAF and GMV, followed by feature selection using the least absolute shrinkage and selection operator regression and recursive feature elimination algorithms. Multiple predictive models were constructed and the final model with the smallest predictive residuals was chosen. The model performance was evaluated using the area under the receiver operating characteristic (ROCAUC) curve, area under the precision-recall curve (PRAUC), balance accuracy (BACC), sensitivity, F1 score, positive predictive value (PPV), and negative predictive value (NPV). External validation was performed using a public database. Then, correlation analysis was performed between the neuroimaging predictors and clinical features in migraine.

RESULTS

One hundred eighteen patients with migraine (59 responders and 59 non-responders) were enrolled. Six features (PerAF of left insula and left transverse temporal gyrus; and GMV of right superior frontal gyrus, left postcentral gyrus, right postcentral gyrus, and left precuneus) were observed. The random forest model with the lowest predictive residuals was selected and model metrics (ROCAUC, PRAUC, BACC, sensitivity, F1 score, PPV, and NPV) in the training and testing groups were 0.982, 0.983, 0.927, 0.976, 0.930, 0.889, and 0.973; and 0.711, 0.648, 0.639, 0.667,0.649, 0.632, and 0.647, respectively. The model metrics of external validation were 0.631, 0.651, 0.611, 0.808, 0.656, 0.553, and 0.706. Additionally, a significant positive correlation was found between the GMV of the left precuneus and attack time in non-responders.

CONCLUSIONS

Our findings suggest the potential of multimodal neuroimaging features in predicting the efficacy of NSAIDs in migraine treatment and provide novel insights into the neural mechanisms underlying migraine and its optimized treatment strategy.

Using ALE coordinate-based meta-analysis to observe resting-state brain abnormalities in subjective tinnitus

The origin of tinnitus remains a topic of discussion; however, numerous resting-state functional magnetic resonance imaging (rsfMRI) studies interpret it as a disruption in neural functional connectivity. Yet, there's notable inconsistency in the resting-state data across these studies. To shed light on this discrepancy, we conducted a meta-analysis of extant rsfMRI studies, aiming to identify potential regions that consistently signify core abnormalities in individuals with tinnitus.

METHODS

A systematic search on MEDLINE/PubMed, Google Scholar, and Scopus databases was performed to identify rsfMRI studies on tinnitus published up to October 2022. Coordinates related to the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) brain maps that showed significant differences between tinnitus patients and controls were extracted. Meta-analysis was performed using the activation likelihood estimation method. Data were included from 17 rsfMRI studies that reported a total of 63 distinct foci in ALFF and 46 foci in ReHo.

RESULTS

Our meta-analysis revealed several regions where tinnitus patients demonstrated increased ALFF and ReHO values, both individually and collectively, when compared to control subjects. These regions encompassed the insula, middle temporal gyrus, and inferior frontal gyrus on both sides. Additionally, increased activity was also noted in the cerebellum posterior lobe bilaterally and the right superior frontal gyrus.

CONCLUSIONS

This meta-analysis demonstrates a unique pattern of resting-state brain abnormalities involving both the auditory and non-auditory brain regions as neuroimaging markers, which helps understand the neuro-pathophysiological mechanisms of tinnitus.

The effects of mobile phone dependence on athletic performance and its mechanisms

Mobile phone dependence (also known as internet dependence, MPD), defined as a problematic behavior characterized by excessive use or intermittent craving to use a mobile phone, results in various social, behavioral, and affective problems in daily life. In sports, MPD is directly related to the physical and mental health and sports performance of athletes. The individual and environmental factors, neurobiological mechanisms and theoretical models of MPD affecting athletic performance were analyzed by reviewing previous studies, aiming to construct effective training and development protocols to prevent and control the occurrence of MPD in athletes. At present, athletic performance can be affected by MPD through individual factors and environmental factors. The neurobiological mechanisms between the two are based on the brain reward system and microwave radiation from mobile phones, with athletic performance being restricted by alterations in the corresponding brain regions. Relevant theoretical models mainly include the social cognitive model of self-regulation and the integrative model of self-control, which explain the interrelationship between MPD and athletic performance from the perspectives of athletes' self-regulation and self-control, respectively. As an emerging phenomenon, the influence pathways and mechanisms by which MPD affects athletic performance need to be further investigated. A longitudinal perspective should be adopted to trace the dynamic impact relationship between the two, and developing relevant theoretical frameworks from an interdisciplinary research perspective should be valuable for providing theoretical support for coaches and sports administrators to formulate scientific training protocols and thus improve the mental health of athletes.

Circulatory shock associated with left insular stroke and chronic steroid treatment

BACKGROUND

Damage to the insula has been associated with various types of cardiovascular dysfunction, including arrhythmias and blood pressure imbalances. Acute neuroendocrine disturbances following insular damage have also been described.

CASE PRESENTATION

A 50-year-old right-handed man with a left insular ischemic lesion exhibited aphasia and right central VII nerve palsy. Five days after the stroke, the patient exhibited severe bradycardia and hypotension. He had been treated for ocular trauma with prednisone for the preceding 3 weeks. Cortisol and adrenocorticotropic hormone levels indicated secondary adrenal insufficiency. Despite adequate fluid intake, the patient's blood pressure dropped, requiring norepinephrine administration. Midodrine was also initiated, leading to clinical improvement. The therapy was gradually discontinued as vital signs normalized. By Day 24, electrocardiogram monitoring was unremarkable, hormonal levels normalized, and the neurological examination revealed only mild residual speech fluency impairment. Computed tomography scans confirmed a recovering ischemic lesion of the left insula.

CONCLUSIONS

This case reveals the inhibitory effect exerted by a left-sided insular stroke on the autonomic system. It also highlights the still largely unexplored neuroendocrine complications of damage to this brain region.

Pharmacological Manipulation of Corticotropin-Releasing Factor Receptors in the Anterior and Posterior Subregions of the Insular Cortex Differently Affects Anxiety-Like Behaviors in the Elevated Plus Maze in Rats

Neuroimaging data in humans and neurobiological studies in rodents have suggested an involvement of the insular cortex (IC) in anxiety manifestations. However, the local neurochemical mechanisms involved are still poorly understood. Corticotropin-releasing factor (CRF) neurotransmission has been described as a prominent neurochemical mechanism involved in the expression of anxiety-like behaviors, but the brain sites related are poorly understood. Additionally, several findings indicate that control of physiological and behavioral responses by the IC occurs in a site-specific manner along its rostrocaudal axis. Thus, this study is aimed at evaluating the effect of CRF receptor agonism and antagonism within the anterior and posterior subregions of the IC in controlling anxiety-related behaviors in the elevated plus maze (EPM). For this, independent groups (six groups) of animals received bilateral microinjections of vehicle, the selective CRF1 receptor antagonist CP376395, or CRF into either the anterior or posterior subregions of the IC. Ten minutes later, the behavior in the EPM was evaluated for five minutes. Treatment of the anterior IC with CP376395, but not with CRF, increased the time and number of entries into the open arms of the EPM. CRF, but not the CRF1 receptor antagonist, microinjected into the posterior IC also increased exploration of the EPM open arms. Taken together, these data indicate that CRFergic neurotransmission in the anterior IC is involved in the expression of anxiety-related behaviors in the EPM. This neurochemical mechanism does not seem to be activated within the posterior IC during exposure to the EPM, but the effects caused by CRF microinjection indicate that activation of CRF receptors in this IC subregion might evoke anxiolytic-like effects.

The role of pain modulation pathway and related brain regions in pain

Pain is a multifaceted process that encompasses unpleasant sensory and emotional experiences. The essence of the pain process is aversion, or perceived negative emotion. Central sensitization plays a significant role in initiating and perpetuating of chronic pain. Melzack proposed the concept of the "pain matrix", in which brain regions associated with pain form an interconnected network, rather than being controlled by a singular brain region. This review aims to investigate distinct brain regions involved in pain and their interconnections. In addition, it also sheds light on the reciprocal connectivity between the ascending and descending pathways that participate in pain modulation. We review the involvement of various brain areas during pain and focus on understanding the connections among them, which can contribute to a better understanding of pain mechanisms and provide opportunities for further research on therapies for improved pain management.

Morphological study of neuropeptide Y expression in human and mouse anterior insular cortex: Overexpression in the insular cortex and nucleus accumbens in obese mice on a long-term obesogenic diet

BACKGROUND

The anterior lobe of the insular cortex (aINS) is a cortical region that has reciprocal connections with limbic centers such as the anterior cingulate cortex, prefrontal cortex, amygdala and nucleus accumbens (NAc). In fact, the aINS has been involved in the integration of autonomic information for emotional and motivational functions. The compulsive consumption of drugs or high-fat foods induces alterations at both behavioural and brain levels. Brain reward circuits are altered in response to continued intake, in particular the dopaminergic projections from the ventral tegmental area (VTA) to the NAc. The aINS has multiple connections with the components of this system. In recent years, efforts have been made to better understand the fundamental role of the aINS in addiction, making it one of the key centres of interest for research into new treatments for addiction.

OBJECTIVES

The present work focuses on studying 1.- whether the human aINS expresses orexigenic peptides such as neuropeptide Y (NPY), a peptide known to induce hyperphagia, and which has been implicated in the onset and development of obesity, 2.- the long-term effect of an obesogenic diet on NPY expression in the aINS and NAc of C57BL/6 mice.

METHODS

A total of 17 female C57BL/6 J mice were used in this study. Female mice were fed ad libitum with water and, either a standard diet (SD) or a high-fat diet (HFD) to induce obesity. There were seven female mice on the SD and ten on the HFD. The duration of the experiment was 180 days. We also studied 3 human adult brains (1 male and 2 females, mean age 55.7 ± 5.2 years). The morphological study was performed using immunohistochemistry and double immunofluorescence techniques to study the neurochemical profile of NPY neurons of the aINS and NAc of humans and mice.

RESULTS

Our morphological analysis demonstrates for the first time the basal expression of NPY in different layers of the human cortex (II, III, IV, V/VI), in a pattern similar to previous studies in other species. Furthermore, we observed an increase in the number of NPY-positive cells and their intracytoplasmic signal in the aINS and NAc of the obese mice subjected to a long-term obesogenic diet.

CONCLUSIONS

To our knowledge, this is the first study to show the distribution and expression of NPY in the human INS and how its expression is altered after prolonged treatment with an obesogenic diet in obese mice. Our findings may contribute to the understanding of the pathophysiological mechanisms underlying obesity in regions related to the reward system and associated with uncontrolled intake of high-fat foods, thus facilitating the identification of novel therapeutic targets.

Connectivity differences between inferior frontal gyrus and mentalizing network in autism as compared to developmental coordination disorder and non-autistic youth

Prior studies have compared neural connectivity during mentalizing tasks in autism (ASD) to non-autistic individuals and found reduced connectivity between the inferior frontal gyrus (IFG) and mentalizing regions. However, given that the IFG is involved in motor processing, and about 80% of autistic individuals have motor-related difficulties, it is necessary to explore if these differences are specific to ASD or instead similar across other developmental motor disorders, such as developmental coordination disorder (DCD). Participants (29 ASD, 20 DCD, 31 typically developing [TD]; ages 8-17) completed a mentalizing task in the fMRI scanner, where they were asked to think about why someone was performing an action. Results indicated that the ASD group, as compared to both TD and DCD groups, showed significant functional connectivity differences when mentalizing about other's actions. The left IFG seed revealed ASD connectivity differences with the: bilateral temporoparietal junction (TPJ), left insular cortex, and bilateral dorsolateral prefrontal cortex (DLPFC). Connectivity differences using the right IFG seed revealed ASD differences in the: left insula, and right DLPFC. These results indicate that connectivity differences between the IFG, mentalizing regions, emotion and motor processing regions are specific to ASD and not a result of potentially co-occurring motor differences.

Investigating the heterogeneity within the somatosensory-motor network and its relationship with the attention and default systems

The somatosensory-motor network (SMN) not only plays an important role in primary somatosensory and motor processing but is also central to many disorders. However, the SMN heterogeneity related to higher-order systems still remains unclear. Here, we investigated SMN heterogeneity from multiple perspectives. To characterize the SMN substructures in more detail, we used ultra-high-field functional MRI to delineate a finer-grained cortical parcellation containing 430 parcels that is more homogenous than the state-of-the-art parcellation. We personalized the new parcellation to account for individual differences and identified multiscale individual-specific brain structures. We found that the SMN subnetworks showed distinct resting-state functional connectivity (RSFC) patterns. The Hand subnetwork was central within the SMN and exhibited stronger RSFC with the attention systems than the other subnetworks, whereas the Tongue subnetwork exhibited stronger RSFC with the default systems. This two-fold differentiation was observed in the temporal ordering patterns within the SMN. Furthermore, we characterized how the distinct attention and default streams were carried forward into the functions of the SMN using dynamic causal modeling and identified two behavioral domains associated with this SMN fractionation using meta-analytic tools. Overall, our findings provided important insights into the heterogeneous SMN organization at the system level and suggested that the Hand subnetwork may be preferentially involved in exogenous processes, whereas the Tongue subnetwork may be more important in endogenous processes.

Elevated Insulin Levels Engage the Salience Network during Multisensory Perception

INTRODUCTION

Brain insulin reactivity has been reported in connection with systematic energy metabolism, enhancement in cognition, olfactory sensitivity, and neuroendocrine circuits. High receptor densities exist in regions important for sensory processing. The main aim of the study was to examine whether intranasal insulin would modulate the activity of areas in charge of olfactory-visual integration.

METHODS

As approach, a placebo-controlled double-blind within crossover design was chosen. The experiments were conducted in a research unit of a university hospital. On separate mornings, twenty-six healthy normal-weight males aged between 19 and 31 years received either 40 IU intranasal insulin or placebo vehicle. Subsequently, they underwent 65 min of functional magnetic resonance imaging whilst performing an odor identification task. Functional brain activations of olfactory, visual, and multisensory integration as well as insulin versus placebo were assessed. Regarding the odor identification task, reaction time, accuracy, pleasantness, and intensity measurements were taken to examine the role of integration and treatment. Blood samples were drawn to control for peripheral hormone concentrations.

RESULTS

Intranasal insulin administration during olfactory-visual stimulation revealed strong bilateral engagement of frontoinsular cortices, anterior cingulate, prefrontal cortex, mediodorsal thalamus, striatal, and hippocampal regions (p ≤ 0.001 familywise error [FWE] corrected). In addition, the integration contrast showed increased activity in left intraparietal sulcus, left inferior frontal gyrus, left superior frontal gyrus, and left middle frontal gyrus (p ≤ 0.013 FWE corrected).

CONCLUSIONS

Intranasal insulin application in lean men led to enhanced activation in multisensory olfactory-visual integration sites and salience hubs which indicates stimuli valuation modulation. This effect can serve as a basis for understanding the connection of intracerebral insulin and olfactory-visual processing.

Distinct resting-state functional connectivity patterns of Anterior Insula affected by smoking in mild cognitive impairment

Smoking is a modifiable risk factor for Alzheimer's disease (AD). The insula plays a vital role in both smoking and cognition. However, the smoking effects on insula-related networks in cognitively normal controls (CN) and mild cognitive impairment (MCI) patients remain unknown. We identified 129 CN (85 non-smokers and 44 smokers) and 83 MCI (54 non-smokers and 29 smokers). Each underwent neuropsychological assessment and MRI (structural and resting-state functional). Seed-based functional analyses in the anterior and posterior insula were performed to calculate the functional connectivity (FC) with voxels in the whole brain. Mixed-effect analyses were performed to explore the interactive effects on smoking and cognitive status. Associations between FC and neuropsychological scales were assessed. Mixed-effect analyses revealed the FC differences between the right anterior insula (RAI) with the left middle temporal gyrus (LMTG) and that with the right inferior parietal lobule (RIPL) (p < 0.01, cluster level < 0.05, two-tailed, gaussian random field correction). The FC of RAI in both LMTG and RIPL sees a significant decrease in MCI smokers (p < 0.01). Smoking affects insula FC differently between MCI and CN, and could decrease the insula FC in MCI patients. Our study provides evidence of neural mechanisms between smoking and AD.

Excessively increased thalamocortical connectivity and poor initial antiseizure medication response in epilepsy patients

Objectives

The network mechanism underlying the initial response to antiseizure medication in epilepsy has not been revealed yet. Given the central role of the thalamus in the brain network, we conducted a case-control study to investigate the association between thalamic connectivity and medication response.

Methods

We recruited 39 patients with newly diagnosed and medication-naïve epilepsy of genetic or unknown etiology, including 26 with a good response (GR group) and 13 with a poor response (PR group), and 26 matched healthy participants (control group). We measured the gray matter density (GMD) and the amplitude of low-frequency fluctuation (ALFF) of bilateral thalami. We then set each thalamus as the seed region of interest (ROI) to calculate voxel-wise functional connectivity (FC) and assessed ROI-wise effective connectivity (EC) between the thalamus and targeted regions.

Results

We found no significant difference between groups in the GMD or ALFF of bilateral thalami. However, we observed that the FC values of several circuits connecting the left thalamus and the cortical areas, including the bilateral Rolandic operculum, the left insula, the left postcentral gyrus, the left supramarginal gyrus, and the left superior temporal gyrus, differed among groups (False Discovery Rate correction, P < 0.05), with a higher value in the PR group than in the GR group and/or the control group (Bonferroni correction, P < 0.05). Similarly, both the outflow and the inflow EC in each thalamocortical circuit were higher in the PR group than in the GR group and the control group, although these differences did not remain statistically significant after applying the Bonferroni correction (P < 0.05). The FC showed a positive correlation with the corresponding outflow and inflow ECs for each circuit.

Conclusion

Our finding suggested that patients with stronger thalamocortical connectivity, potentially driven by both thalamic outflowing and inflowing information, may be more likely to respond poorly to initial antiseizure medication.

Association of gait speed with regional brain volumes and risk of dementia in older Japanese: The Hisayama study

BACKGROUND

To investigate the association of gait speed with regional brain volumes and the risk of incident dementia.

METHODS

A total of 1112 dementia-free Japanese residents aged ≥65 years who underwent brain magnetic resonance imaging were followed for 5.0 years (median). The participants were classified into the age- and sex-specific quartile levels of maximum gait speed. Regional gray matter volumes (GMV) and white matter hyperintensities volumes (WMHV) were measured by applying voxel-based morphometry methods. The cross-sectional association of maximum gait speed with regional GMV was examined using an analysis of covariance. We also estimated the association between maximum gait speed level and the risk of developing dementia using a Cox proportional hazards model. Mediation analyses were conducted to determine the contribution of regional brain volumes to the association between maximum gait speed and dementia.

RESULTS

Lower maximum gait speed was significantly associated with lower GMV of the total brain, frontal lobe, temporal lobe, cingulate gyrus, insula, hippocampus, amygdala, basal ganglia, thalamus, and cerebellum, and increased WMHV at baseline. During the follow-up, 108 participants developed dementia. The incidence rate of all dementias increased significantly with decreasing maximum gait speed after adjusting for potential confounders (P for trend = 0.03). The mediating effects of the GMV of the hippocampus, GMV of the insula, and WMHV were significant.

CONCLUSIONS

Lower maximum gait speed was significantly associated with an increased risk of dementia. Reduced GMV of the hippocampus or insula, and an increase in WMHV was likely to be involved in this association.

Sex differences in brain metabolic connectivity architecture in probable dementia with Lewy bodies

We investigated how sex modulates metabolic connectivity alterations in probable dementia with Lewy bodies (pDLB). We included 131 pDLB patients (males/females: 58/73) and similarly aged healthy controls (HC) (male/female: 59/75) with available (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans. We assessed (1) sex differences in the whole-brain connectivity, identifying pathological hubs, (2) connectivity alterations in functional pathways of the neurotransmitter systems, (3) Resting State Networks (RSNs) integrity. Both pDLB_M (males) and pDLB_F (females) shared dysfunctional hubs in the insula, Rolandic operculum, and inferior parietal lobule, but the pDLB_M group showed more severe and diffuse whole-brain connectivity alterations. Neurotransmitters connectivity analysis revealed common alterations in dopaminergic and noradrenergic pathways. Sex differences emerged particularly in the Ch4-perisylvian division, with pDLB_M showing more severe alterations than pDLB_F. The RSNs analysis showed no sex differences, with decreased connectivity strength in the primary visual, posterior default mode, and attention networks in both groups. Extensive connectivity changes characterize both males and females in the dementia stage, with a major vulnerability of cholinergic neurotransmitter systems in males, possibly contributing to the observed different clinical phenotypes.

A Unique "Reversed" Migration of Neurons in the Developing Claustrum

The claustrum (CLA) is a cluster of neurons located between the insular cortex and striatum. Many studies have shown that the CLA plays an important role in higher brain function. Additionally, growing evidence suggests that CLA dysfunction is associated with neuropsychological symptoms. However, how the CLA is formed during development is not fully understood. In the present study, we analyzed the development of the CLA, especially focusing on the migration profiles of CLA neurons in mice of both sexes. First, we showed that CLA neurons were generated between embryonic day (E) 10.5 and E12.5, but mostly at E11.5. Next, we labeled CLA neurons born at E11.5 using the FlashTag technology and revealed that most neurons reached the brain surface by E13.5 but were distributed deep in the CLA 1 d later at E14.5. Time-lapse imaging of GFP-labeled cells revealed that some CLA neurons first migrated radially outward and then changed their direction inward after reaching the surface. Moreover, we demonstrated that Reelin signal is necessary for the appropriate distribution of CLA neurons. The switch from outward to "reversed" migration of developing CLA neurons is distinct from other migration modes, in which neurons typically migrate in a certain direction, which is simply outward or inward. Future elucidation of the characteristics and precise molecular mechanisms of CLA development may provide insights into the unique cognitive functions of the CLA.SIGNIFICANCE STATEMENT The claustrum (CLA) plays an important role in higher brain function, and its dysfunction is associated with neuropsychological symptoms. Although psychiatric disorders are increasingly being understood as disorders of neurodevelopment, little is known about CLA development, including its neuronal migration profiles and underlying molecular mechanisms. Here, we investigated the migration profiles of CLA neurons during development and found that they migrated radially outward and then inward after reaching the surface. This switch in the migratory direction from outward to inward may be one of the brain's fundamental mechanisms of nuclear formation. Our findings enable us to investigate the relationship between CLA maldevelopment and dysfunction, which may facilitate understanding of the pathogenesis of some psychiatric disorders.

Sodium Intake and Disease: Another Relationship to Consider

Sodium (Na+) is crucial for numerous homeostatic processes in the body and, consequentially, its levels are tightly regulated by multiple organ systems. Sodium is acquired from the diet, commonly in the form of NaCl (table salt), and substances that contain sodium taste salty and are innately palatable at concentrations that are advantageous to physiological homeostasis. The importance of sodium homeostasis is reflected by sodium appetite, an "all-hands-on-deck" response involving the brain, multiple peripheral organ systems, and endocrine factors, to increase sodium intake and replenish sodium levels in times of depletion. Visceral sensory information and endocrine signals are integrated by the brain to regulate sodium intake. Dysregulation of the systems involved can lead to sodium overconsumption, which numerous studies have considered causal for the development of diseases, such as hypertension. The purpose here is to consider the inverse-how disease impacts sodium intake, with a focus on stress-related and cardiometabolic diseases. Our proposition is that such diseases contribute to an increase in sodium intake, potentially eliciting a vicious cycle toward disease exacerbation. First, we describe the mechanism(s) that regulate each of these processes independently. Then, we highlight the points of overlap and integration of these processes. We propose that the analogous neural circuitry involved in regulating sodium intake and blood pressure, at least in part, underlies the reciprocal relationship between neural control of these functions. Finally, we conclude with a discussion on how stress-related and cardiometabolic diseases influence these circuitries to alter the consumption of sodium.

The role of the insula in cognitive impairment of schizophrenia

Cognitive impairment is one of the core clinical symptom domains of schizophrenia. Research shows that cognitive deficits in this neuropsychiatric syndrome is associated with neurodevelopmental pathology affecting multiple brain regions such as the dorsolateral prefrontal cortex, the hippocampus and the parietal lobe. The insula is a relatively small structure that is highly connected with several brain regions as well as multiple brain networks. A large number of studies have reported the involvement of the insula in many of the psychotic and nonpsychotic manifestations of schizophrenia. Here we review the role of the insula as a hub across key neurocircuits which have been implicated in the various cognitive pathologies in schizophrenia. Structural and functional abnormalities in the right and left insulae may serve as a biomarker for susceptibility to schizophrenia.

Transforming experiences: Neurobiology of memory updating/editing

Long-term memory is achieved through a consolidation process where structural and molecular changes integrate information into a stable memory. However, environmental conditions constantly change, and organisms must adapt their behavior by updating their memories, providing dynamic flexibility for adaptive responses. Consequently, novel stimulation/experiences can be integrated during memory retrieval; where consolidated memories are updated by a dynamic process after the appearance of a prediction error or by the exposure to new information, generating edited memories. This review will discuss the neurobiological systems involved in memory updating including recognition memory and emotional memories. In this regard, we will review the salient and emotional experiences that promote the gradual shifting from displeasure to pleasure (or vice versa), leading to hedonic or aversive responses, throughout memory updating. Finally, we will discuss evidence regarding memory updating and its potential clinical implication in drug addiction, phobias, and post-traumatic stress disorder.

Functional connectivity alterations in migraineurs with Alice in Wonderland syndrome

BACKGROUND AND PURPOSE

Alice in Wonderland syndrome (AIWS) is a neurological disorder characterized by erroneous perception of the body schema or surrounding space. Migraine is the primary cause of AIWS in adults. The pathophysiology of AIWS is largely unknown, especially regarding functional abnormalities. In this study, we compared resting-state functional connectivity (FC) of migraine patients experiencing AIWS, migraine patients with typical aura (MA) and healthy controls (HCs).

METHODS

Twelve AIWS, 12 MA, and 24 HCs were enrolled and underwent 3 T MRI scanning. Independent component analysis was used to identify RSNs thought to be relevant for AIWS: visual, salience, basal ganglia, default mode, and executive control networks. Dual regression technique was used to detect between-group differences in RSNs. Finally, AIWS-specific FC alterations were correlated with clinical measures.

RESULTS

With respect to HCs, AIWS and MA patients both showed significantly lower (p < 0.05, FDR corrected) FC in lateral and medial visual networks and higher FC in salience and default mode networks. AIWS patients alone showed higher FC in basal ganglia and executive control networks than HCs. When directly compared, AIWS patients showed lower FC in visual networks and higher FC in all other investigated RSNs than MA patients. Lastly, AIWS-specific FC alterations in the executive control network positively correlated with migraine frequency.

CONCLUSIONS

AIWS and MA patients showed similar FC alterations in several RSNs, although to a different extent, suggesting common pathophysiological underpinnings. However, AIWS patients showed additional FC alterations, likely due to the complexity of AIWS symptoms involving high-order associative cortical areas.

The Relationship Between Physical Activity and Mobile Phone Addiction Among Adolescents and Young Adults: Systematic Review and Meta-analysis of Observational Studies

BACKGROUND

Previous studies have reported a potential negative correlation between physical activity (PA) and mobile phone addiction (MPA) among adolescents and young adults. To date, the strength of this correlation has not been well characterized.

OBJECTIVE

This review and meta-analysis aimed to synthesize available empirical studies to examine the correlations between PA and MPA among adolescents and young adults. We also explored several potential moderators, including time of data collection, country or region, and type of population, associated with the relationship between PA and MPA.

METHODS

Four electronic databases (PubMed, Scopus, PsycINFO, and Web of Science) were searched from database inception to March 2022 to identify relevant studies. The pooled Pearson correlation coefficients and their corresponding 95% CIs for the relationship between PA and MPA were calculated using the inverse variance method. The methodological quality of the included cross-sectional studies was determined based on the Joanna Briggs Institute appraisal checklist. The study conformed to the PRISMA (Preferred Reporting Items for Systematic Review and Meta-analyses) guidelines.

RESULTS

In total, 892 relevant articles were identified, of which 22 were selected based on the inclusion and exclusion criteria. The final meta-analysis included 17 of the 22 studies. Results of random effects modeling revealed a moderate correlation between PA and MPA among adolescents and young adults (summary r=-0.243, P<.001). Sensitivity and publication bias analyses further demonstrated the robustness of our results. All the included studies were scored as high quality with a low risk of bias. Subgroup analysis further indicated that none of the hypothesized moderators (time of data collection, country or region, and type of population) significantly affected the relationship between PA and MPA, as confirmed by the mixed effects analysis. In addition, in the data collection subgroups, medium effect sizes were obtained for data collected before COVID-19 (r=-0.333, P<.001) and data collected during COVID-19 (r=-0.207, P<.001). In subgroup analyses for country or region, the correlation coefficient for China and other developing regions showed a similarly moderate effect size (r=-0.201, P<.001 and r= -0.217, P<.001, respectively). However, the effect sizes for developed regions were not significant (r=-0.446, P=.39). In a subgroup analysis based on the type of population, we found that the effect size for young adults was moderate (r=-0.250, P<.001). However, that of adolescents was not significant (r=-0.129, P=.24).

CONCLUSIONS

Our results demonstrate a moderately negative relationship between PA and MPA among young adults. The strength of this relationship was not influenced by the time of data collection, country or region, or type of population.

Primate preoptic neurons drive hypothermia and cold defense

Maintaining body temperature within a narrow range is vital for warm-blooded animals. In rodents, the preoptic area (POA) of the hypothalamus detects and regulates core body temperature. However, knowledge about the thermal regulation center in primates remains limited. Here, we show that activating a subpopulation of POA neurons by a chemogenetic strategy reliably induces hypothermia in anesthetized and freely moving macaques. Comprehensive monitoring of physiological parameters reveals that such hypothermia is accompanied by autonomic changes including a rise in heart rate, skeletal muscle activity, and correlated biomarkers in blood. Consistent with enhanced ambulatory movement during hypothermia, the animals show a full range of cold-defense behaviors. Resting-state fMRI confirms the chemogenetic activation of POA and charts a brain-wide network of thermoregulation. Altogether, our findings demonstrate the central regulation of body temperature in primates and pave the way for future application in clinical practice.

Structural alterations of the insula in depression patients - A 7-Tesla-MRI study

INTRODUCTION

The insular cortex is part of a network of highly connected cerebral "rich club" - regions and has been implicated in the pathophysiology of various psychiatric and neurological disorders, of which major depressive disease is one of the most prevalent. "Rich club" vulnerability can be a contributing factor in disease development. High-resolution structural subfield analysis of insular volume in combination with cortical thickness measurements and psychological testing might elucidate the way in which the insula is changed in depression.

MATERIAL AND METHODS

High-resolution structural images of the brain were acquired using a 7T-MRI scanner. The mean grey matter volume and cortical thickness within the insular subfields were analysed using voxel-based morphometry (VBM) and surface analysis techniques respectively. Insular subfields were defined according to the Brainnetome Atlas for VBM - and the Destrieux-Atlas for cortical thickness - analysis. Thirty-three patients with confirmed major depressive disease, as well as thirty-one healthy controls matched for age and gender, were measured. The severity of depression in MDD patients was measured via a BDI-II score and objective clinical assessment (AMDP). Intergroup statistical analysis was performed using ANCOVA. An intragroup multivariate regression analysis of patient psychological test results was calculated. Corrections for multiple comparisons was performed using FDR.

RESULTS

Significant differences between groups were observed in the left granular dorsal insula according to VBM-analysis. AMDP-scores positively correlated with cortical thickness in the right superior segment of the circular insular sulcus.

CONCLUSIONS

The combination of differences in grey matter volume between healthy controls and patients with a positive correlation of cortical thickness with disease severity underscores the insula's role in the pathogeneses of MDD. The connectivity hub insular cortex seems vulnerable to disruption in context of affective disease.

Functional connectivity gradients of the insula to different cerebral systems

The diverse functional roles of the insula may emerge from its heavy connectivity to an extensive network of cortical and subcortical areas. Despite several previous attempts to investigate the hierarchical organization of the insula by applying the recently developed gradient approach to insula-to-whole brain connectivity data, little is known about whether and how there is variability across connectivity gradients of the insula to different cerebral systems. Resting-state functional MRI data from 793 healthy subjects were used to discover and validate functional connectivity gradients of the insula, which were computed based on its voxel-wise functional connectivity profiles to distinct cerebral systems. We identified three primary patterns of functional connectivity gradients of the insula to distinct cerebral systems. The connectivity gradients to the higher-order transmodal associative systems, including the prefrontal, posterior parietal, temporal cortices, and limbic lobule, showed a ventroanterior-dorsal axis across the insula; those to the lower-order unimodal primary systems, including the motor, somatosensory, and occipital cortices, displayed radiating transitions from dorsoanterior toward both ventroanterior and dorsoposterior parts of the insula; the connectivity gradient to the subcortical nuclei exhibited an organization along the anterior-posterior axis of the insula. Apart from complementing and extending previous literature on the heterogeneous connectivity patterns of insula subregions, the presented framework may offer ample opportunities to refine our understanding of the role of the insula in many brain disorders.

Detection of functional activity in brain white matter using fiber architecture informed synchrony mapping

A general linear model is widely used for analyzing fMRI data, in which the blood oxygenation-level dependent (BOLD) signals in gray matter (GM) evoked in response to neural stimulation are modeled by convolving the time course of the expected neural activity with a canonical hemodynamic response function (HRF) obtained a priori. The maps of brain activity produced reflect the magnitude of local BOLD responses. However, detecting BOLD signals in white matter (WM) is more challenging as the BOLD signals are weaker and the HRF is different, and may vary more across the brain. Here we propose a model-free approach to detect changes in BOLD signals in WM by measuring task-evoked increases of BOLD signal synchrony in WM fibers. The proposed approach relies on a simple assumption that, in response to a functional task, BOLD signals in relevant fibers are modulated by stimulus-evoked neural activity and thereby show greater synchrony than when measured in a resting state, even if their magnitudes do not change substantially. This approach is implemented in two technical stages. First, for each voxel a fiber-architecture-informed spatial window is created with orientation distribution functions constructed from diffusion imaging data. This provides the basis for defining neighborhoods in WM that share similar local fiber architectures. Second, a modified principal component analysis (PCA) is used to estimate the synchrony of BOLD signals in each spatial window. The proposed approach is validated using a 3T fMRI dataset from the Human Connectome Project (HCP) at a group level. The results demonstrate that neural activity can be reliably detected as increases in fMRI signal synchrony within WM fibers that are engaged in a task with high sensitivities and reproducibility.

Late relapse of anti-N-methyl-d-aspartate receptor encephalitis with amusia and transiently reduced uptake in 123I-iomazenil single-photon emission computed tomography

INTRODUCTION

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis has a high relapse rate at approximately 10-20%. Most relapses occur within 2 years from onset, and 5 years after onset is rare. We report a case of anti-NMDAR encephalitis relapse with amusia 10 years after the initial encephalitis and discuss the usefulness of ¹²³I-iomazenil single-photon emission computerized tomography (IMZ-SPECT) for its diagnosis.

CASE

A 13-year-old left-handed girl presented with a depressed level of consciousness and focal to bilateral tonic-clonic seizures. Cerebrospinal fluid (CSF) analysis showed a mildly increased white blood cell count, elevated neopterin levels, and positive oligoclonal bands. Brain MRI was normal. IMZ-SPECT revealed reduced uptake in the right frontoparietal region. She received intravenous pulse methylprednisolone (IVMP) and high-dose intravenous immunoglobulin for autoimmune encephalitis; her symptoms resolved without neurological deficits. At 23 years old, she had mild right-sided numbness, dysarthria, amusia, and tonic-clonic seizures. Although the CSF analysis and brain MRI were normal, IMZ-SPECT revealed reduced uptake, indicating a relapse of encephalitis. IVMP administration resolved the symptoms. After discharge, the initial and relapse CSF analysis revealed anti-NMDAR antibodies.

CONCLUSION

An anti-NMDAR encephalitis relapse 10 years after onset has never been reported. IMZ-SPECT may help in the diagnosis of anti-NMDAR encephalitis.