A brief real-time fNIRS-informed neurofeedback training of the prefrontal cortex changes brain activity and connectivity during subsequent working memory challenge

Working memory (WM) represents a building-block of higher cognitive functions and a wide range of mental disorders are associated with WM impairments. Initial studies have shown that several sessions of functional near-infrared spectroscopy (fNIRS) informed real-time neurofeedback (NF) allow healthy individuals to volitionally increase activity in the dorsolateral prefrontal cortex (DLPFC), a region critically involved in WM. For the translation to therapeutic or neuroenhancement applications, however, it is critical to assess whether fNIRS-NF success transfers into neural and behavioral WM enhancement in the absence of feedback. We therefore combined single-session fNIRS-NF of the left DLPFC with a randomized sham-controlled design (N = 62 participants) and a subsequent WM challenge with concomitant functional MRI. Over four runs of fNIRS-NF, the left DLPFC NF training group demonstrated enhanced neural activity in this region, reflecting successful acquisition of neural self-regulation. During the subsequent WM challenge, we observed no evidence for performance differences between the training and the sham group. Importantly, however, examination of the fMRI data revealed that - compared to the sham group - the training group exhibited significantly increased regional activity in the bilateral DLPFC and decreased left DLPFC - left anterior insula functional connectivity during the WM challenge. Exploratory analyses revealed a negative association between DLPFC activity and WM reaction times in the NF group. Together, these findings indicate that healthy individuals can learn to volitionally increase left DLPFC activity in a single training session and that the training success translates into WM-related neural activation and connectivity changes in the absence of feedback. This renders fNIRS-NF as a promising and scalable WM intervention approach that could be applied to various mental disorders.

Resting-state activity and functional connectivity of insula and postcentral gyrus related to psychological resilience in female depressed patients: A preliminary study

BACKGROUND

Psychological resilience is a protective factor of depression. However, the neuroimaging characteristics of the relationship between psychological resilience and brain imaging in depression are not very clear. Our objectives were to explore the brain functional imaging characteristics of different levels of resilience in female patients with depression.

METHODS

Resting-state functional magnetic resonance imaging (rs-fMRI) was performed on 58 female depressed patients. According to the resilience score, participants were divided into three groups: Low resilience (Low-res), Medium resilience (Med-res) and High resilience (High-res). We compared the differences in the amplitude of low-frequency fluctuations (ALFF) and functional connectivity (FC) among the three groups and correlated psychological resilience with ALFF and FC.

RESULTS

According to ALFF, there was a higher activation in RI and RPG in the High-res compared with Med-res and Low-res, but no significant differences between Med-res and Low-res. The FC between the RPG and supramarginal gyrus (SG) in the High-res was significantly stronger than that in the Med-res and the Low-res, and the FC of the Med-res is stronger than that of the Low-res. Both ALFF and FC were positively correlated with the score of resilience.

LIMITATIONS

The sample size of this study was relatively small and it lacked healthy controls. The results of this study could be considered preliminary.

CONCLUSIONS

Among female patients with depression, patients with higher psychological resilience had higher resting state activation in the RI and RPG and had a stronger interaction between the RPG and the SG.

Disengagement of attention with spatial neglect: A systematic review of behavioral and anatomical findings

The present review examined the consequences of focal brain injury on spatial attention studied with cueing paradigms, with a particular focus on the disengagement deficit, which refers to the abnormal slowing of reactions following an ipsilesional cue. Our review supports the established notion that the disengagement deficit is a functional marker of spatial neglect and is particularly pronounced when elicited by peripheral cues. Recent research has revealed that this deficit critically depends on cues that have task-relevant characteristics or are associated with negative reinforcement. Attentional capture by task-relevant cues is contingent on damage to the right temporo-parietal junction (TPJ) and is modulated by functional connections between the TPJ and the right insular cortex. Furthermore, damage to the dorsal premotor or prefrontal cortex (dPMC/dPFC) reduces the effect of task-relevant cues. These findings support an interactive model of the disengagement deficit, involving the right TPJ, the insula, and the dPMC/dPFC. These interconnected regions play a crucial role in regulating and adapting spatial attention to changing intrinsic values of stimuli in the environment.

The insula: Leveraging cellular and systems-level research to better understand its roles in health and schizophrenia

Schizophrenia is a highly heterogeneous disorder characterized by a multitude of complex and seemingly non-overlapping symptoms. The insular cortex has gained increasing attention in neuroscience and psychiatry due to its involvement in a diverse range of fundamental human experiences and behaviors. This review article provides an overview of the insula's cellular and anatomical organization, functional and structural connectivity, and functional significance. Focusing on specific insula subregions and using knowledge gained from humans and preclinical studies of insular tracings in non-human primates, we review the literature and discuss the functional roles of each subregion, including in somatosensation, interoception, salience processing, emotional processing, and social cognition. Building from this foundation, we then extend these findings to discuss reported abnormalities of these functions in individuals with schizophrenia, implicating insular involvement in schizophrenia pathology. This review underscores the insula's vast role in the human experience and how abnormal insula structure and function could result in the wide-ranging symptoms observed in schizophrenia.

Responding to threat: Associations between neural reactivity to and behavioral avoidance of threat in pediatric anxiety

BACKGROUND

Despite broad recognition of the central role of avoidance in anxiety, a lack of specificity in its operationalization has hindered progress in understanding this clinically significant construct. The current study uses a multimodal approach to investigate how specific measures of avoidance relate to neural reactivity to threat in youth with anxiety disorders.

METHODS

Children with anxiety disorders (ages 6-12 years; n = 65 for primary analyses) completed laboratory task- and clinician-based measures of avoidance, as well as a functional magnetic resonance imaging task probing neural reactivity to threat. Primary analyses examined the ventral anterior insula (vAI), amygdala, and ventromedial prefrontal cortex (vmPFC).

RESULTS

Significant but distinct patterns of association with task- versus clinician-based measures of avoidance emerged. Clinician-rated avoidance was negatively associated with right and left vAI reactivity to threat, whereas laboratory-based avoidance was positively associated with right vAI reactivity to threat. Moreover, left vAI-right amygdala and bilateral vmPFC-right amygdala functional connectivity were negatively associated with clinician-rated avoidance but not laboratory-based avoidance.

LIMITATIONS

These results should be considered in the context of the restricted range of our treatment-seeking sample, which limits the ability to draw conclusions about these associations across children with a broader range of symptomatology. In addition, the limited racial and ethnic diversity of our sample may limit the generalizability of findings.

CONCLUSION

These findings mark an important step towards bridging neural findings and behavioral patterns using a multimodal approach. Advancing understanding of behavioral avoidance in pediatric anxiety may guide future treatment optimization by identifying individual-specific targets for treatment.

Longitudinal associations between neighborhood safety and adolescent adjustment: The moderating role of affective neural sensitivity

Research on social determinants of health has highlighted the influence of neighborhood characteristics (e.g., neighborhood safety) on adolescents' health. However, it is less clear how changes in neighborhood environments play a role in adolescent development, and who are more sensitive to such changes. Utilizing the first three waves of data from the Adolescent Brain Cognitive Development (ABCD) project (N = 7932, M (SD) age = 9.93 (.63) years at T1; 51% boys), the present study found that increases in neighborhood safety were associated with decreased adolescent externalizing symptoms, internalizing symptoms, but not sleep disturbance over time, controlling for baseline neighborhood safety. Further, adolescents' insula and anterior cingulate cortex (ACC) reactivity to positive emotional stimuli moderated the association between changes in neighborhood safety and adolescent adjustment. Among youth who showed higher, but not lower, insula and ACC reactivity to positive emotion, increases in neighborhood safety were linked with better adjustment. The current study contributes to the differential susceptibility literature by identifying affective neural sensitivity as a marker of youth's susceptibility to changes in neighborhood environment. The findings highlight the importance of neighborhood safety for youth during the transition to adolescence, particularly for those with heightened affective neural sensitivity.

Climate change on the brain: Neural correlates of climate anxiety

Climate change is a global crisis impacting individuals' mental health. Climate anxiety is an emerging area of interest within popular culture and the scientific community. Yet, little is known about the mechanisms underlying climate anxiety. We provide evidence that climate anxiety is related to gray matter volume in the midcingulate cortex as well as its level of functional connectivity with the insula cortex. These neuroanatomical and neurofunctional features of climate anxiety are involved in identifying and anticipating potential threats within the environment and preparing an appropriate action response to such threats. These neural correlates align with those observed in anxiety disorders. Yet, climate anxiety itself as well as the neural correlates of climate anxiety were related to pro-environmental behavior. This may suggest that the midcingulate and insula are part of a network linked to an adaptive aspect of climate anxiety in motivating behavioral engagement.

Sex differences in anhedonia in bipolar depression: a resting-state fMRI study

Previous studies about anhedonia symptoms in bipolar depression (BD) ignored the unique role of gender on brain function. This study aims to explore the regional brain neuroimaging features of BD with anhedonia and the sex differences in these patients. The resting-fMRI by applying fractional amplitude of low-frequency fluctuation (fALFF) method was estimated in 263 patients with BD (174 high anhedonia [HA], 89 low anhedonia [LA]) and 213 healthy controls. The effects of two different factors in patients with BD were analyzed using a 3 (group: HA, LA, HC) × 2 (sex: male, female) ANOVA. The fALFF values were higher in the HA group than in the LA group in the right medial cingulate gyrus and supplementary motor area. For the sex-by-group interaction, the fALFF values of the right hippocampus, left medial occipital gyrus, right insula, and bilateral medial cingulate gyrus were significantly higher in HA males than in LA males but not females. These results suggested that the pattern of high activation could be a marker of anhedonia symptoms in BD males, and the sex differences should be considered in future studies of BD with anhedonia symptoms.

Localized alterations in cortical thickness and sulcal depth of the cingulo-opercular network in relation to lower reading fluency skills in children with dyslexia

The traditional models of reading development describe how language processing and word decoding contribute to reading comprehension and how impairments in word decoding, a defining feature of dyslexia, affect reading comprehension outcomes. However, these models do not include word and sentence reading (contextual reading) fluency, both of which engage executive functions, with notably decreased performance in children with dyslexia. In the current study, we compared cortical thickness and sulcal depth (CT/SD) in the cingulo-opercular (CO) executive functions brain network in children with dyslexia and typical readers and examined associations with word vs. contextual reading fluency. Overall, CT was lower in insular regions and higher in parietal and caudal anterior cingulate cortex regions in children with dyslexia. Children with dyslexia showed positive correlations between word reading fluency and CT/SD in insular regions, whereas no significant correlations were observed in typical readers. For sentence reading fluency, negative correlations with CT/SD were found in insular regions in children with dyslexia, while positive correlations with SD were found in insular regions in typical readers. These results demonstrate the differential relations between word and sentence reading fluency and anatomical circuitry supporting executive functions in children with dyslexia vs. typical readers. It also suggests that word and sentence reading fluency, relate to morphology of executive function-related regions in children with dyslexia, whereas in typical readers, only sentence reading fluency relates to morphology of executive function regions. The results also highlight the role of the insula within the CO network in reading fluency. Here we suggest that word and sentence reading fluency are distinct components of reading that should each be included in the Simple View of Reading traditional model.

The Predictive Potential of Heart Rate Variability for Depression

Heart rate variability (HRV),a measure of the fluctuations in the intervals between consecutive heartbeats, is an indicator of changes in the autonomic nervous system. A chronic reduction in HRV has been repeatedly linked to clinical depression. However, the chronological and mechanistic aspects of this relationship, between the neural, physiological, and psychopathological levels, remain unclear. In this review we present evidence by which changes in HRV might precede the onset of depression. We describe several pathways that can facilitate this relationship. First, we examine a theoretical model of the impact of autonomic imbalance on HRV and its role in contributing to mood dysregulation and depression. We then highlight brain regions that are regulating both HRV and emotion, suggesting these neural regions, and the Insula in particular, as potential mediators of this relationship. We also present additional possible mediating mechanisms involving the immune system and inflammation processes. Lastly, we support this model by showing evidence that modification of HRV with biofeedback leads to an improvement in some symptoms of depression. The possibility that changes in HRV precede the onset of depression is critical to put to the test, not only because it could provide insights into the mechanisms of the illness but also because it may offer a predictive anddiagnosticphysiological marker for depression. Importantly, it could also help to develop new effective clinical interventions for treating depression.

Dissociable neural correlates of trait and ability emotional intelligence: a resting-state fMRI study

Emotional intelligence (EI) is one's ability to monitor one's own and other's emotions and the use of emotional information to enhance thought and action. Previous behavioral studies have shown that EI is separable into trait EI and ability EI, which are known to have distinct characteristics at the behavioral level. A relevant and unanswered question is whether both forms of EI have a dissociable neural basis. Previous studies have individually explored the neural underpinnings of trait EI and ability EI, but there has been no direct comparison of the neural mechanisms underlying these two types of emotional intelligence. The present study addresses this question by using resting-state fMRI to examine the correlational pattern between the regional amplitude of low-frequency fluctuations (ALFF) of the brain and individuals' trait EI and ability EI scores. We found that trait EI scores were positively correlated with the ALFF in the bilateral superior temporal gyrus, and negatively correlated with the ALFF in the ventral medial prefrontal cortex. In contrast, ability EI scores were positively correlated with the ALFF in the insula. Taken together, these results provide preliminary evidence of dissociable neural substrates between trait EI and ability EI.

Self-consciousness mediated the role of the insula in self-disclosure: Evidence from rs-fMRI data

INTRODUCTION

Self-disclosure is integral to forming intimate connections within interpersonal exchanges. While its advantages are widely acknowledged, the cerebral basis of self-disclosure is not thoroughly understood. Insight into its neural underpinnings is crucial for refining therapeutic approaches, especially for challenges associated with self-disclosure.

METHODS

Our study probed the association between spontaneous neural activity, gauged via resting-state fMRI, and self-disclosure tendencies among 258 healthy university students, employing Regional Homogeneity (ReHo) and behavioral correlation analysis. We also explored the mediating effect of self-consciousness on this relationship.

RESULTS

The ReHo-behavior correlation analysis uncovered that higher ReHo values in the insula are predictive of greater self-disclosure in social settings. Additionally, the mediation analysis identified self-consciousness as a partial intermediary between spontaneous neural activity in the insula and self-disclosure behaviors.

CONCLUSION

The findings imply that decreased similarity in the insula during rest-state may amplify self-conscious emotions such as embarrassment, thus illuminating the cognitive processes that underlie disclosure behaviors. Critically, these insights have practical ramifications for enhancing therapeutic methods and communication skills by aiding individuals in navigating self-consciousness obstacles, thereby promoting more transparent and efficacious self-disclosure.

DRD2 TaqIA polymorphism-related functional connectivity between anterior insula and dorsolateral prefrontal cortex predicts the retention time in heroin-dependent individuals under methadone maintenance treatment

BACKGROUND

Dopamine receptor D2 (DRD2) TaqIA polymorphism has an influence on addiction treatment response and prognosis by mediating brain dopaminergic system efficacy. Insula is crucial for conscious urges to take drugs and maintain drug use. However, it remains unclear about the contribution of DRD2 TaqIA polymorphism to the regulation of insular on addiction behavioral and its relation with the therapeutic effect of methadone maintenance treatment (MMT).

METHODS

57 male former heroin dependents receiving stable MMT and 49 matched male healthy controls (HC) were enrolled. Salivary genotyping for DRD2 TaqA1 and A2 alleles, brain resting-state functional MRI scan and a 24-month follow-up for collecting illegal-drug-use information was conducted and followed by clustering of functional connectivity (FC) patterns of HC insula, insula subregion parcellation of MMT patients, comparing the whole brain FC maps between the A1 carriers and non-carriers and analyzing the correlation between the genotype-related FC of insula sub-regions with the retention time in MMT patients by Cox regression.

RESULTS

Two insula subregions were identified: the anterior insula (AI) and the posterior insula (PI) subregion. The A1 carriers had a reduced FC between the left AI and the right dorsolateral prefrontal cortex (dlPFC) relative to no carriers. And this reduced FC was a poor prognostic factor for the retention time in MMT patients.

CONCLUSION

DRD2 TaqIA polymorphism affects the retention time in heroin-dependent individuals under MMT by mediating the functional connectivity strength between left AI and right dlPFC, and the two brain regions are promising therapeutic targets for individualized treatment.

Cue-exposure treatment influences resting-state functional connectivity-a randomized controlled fMRI study in alcohol use disorder

RATIONALE

Cue-exposure therapy (CET) consists of exposing patients to the cause of their affliction in a controlled environment and after psychological preparation. Ever since it was conceived, it has been suggested as a treatment for different types of behavioural impairments, from anxiety disorders to substance abuse. In the field of addictive behaviour, many different findings have been shown regarding the effectiveness of this therapy.

OBJECTIVES

This study aims to examine the underlying neurobiological mechanisms of the effects of CET in patients with alcohol use disorder using resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

In a randomized, controlled study, we examined patients after inpatient detoxification as well as healthy controls. Patients underwent nine sessions of CET spaced over 3 weeks. Rs-fMRI was conducted before treatment and 3 weeks after treatment onset in patients, healthy controls received only one rs-fMRI measurement. The final participant sample with complete data included 35 patients in the CET group, 17 patients in the treatment-as-usual group, and 43 HCs.

RESULTS

Our results show differences in the Salience Network when comparing the CET group to the treatment-as-usual group (TAU). Functional connectivity between the anterior cingulate Cortex (ACC) and the insula was increased after CET, whereas it was decreased from ACC to the putamen and globus pallidus. Further, increased connectivity with the precuneus was found in the dorsal attention network after cue exposure treatment.

CONCLUSIONS

These findings suggest that cue exposure therapy changes the resting-state brain connectivity with additional effects to the standard psychotherapy treatment. Hence, our study results suggest why including CET in standard therapies might improve the preparation of patients in front of daily situations.

Chemogenetic Modulation of Posterior Insula CaMKIIa Neurons Alters Pain and Thermoregulation

The posterior insular cortex (PIC) is well positioned to perform somatosensory-limbic integration; yet, the function of neuronal subsets within the PIC in processing the sensory and affective dimensions of pain remains unclear. Here, we employ bidirectional chemogenetic modulation to characterize the function of PIC CaMKIIa-expressing excitatory neurons in a comprehensive array of sensory, affective, and thermoregulatory behaviors. Excitatory pyramidal neurons in the PIC were found to be sensitized under inflammatory pain conditions. Chemogenetic activation of excitatory CaMKIIa-expressing PIC neurons in non-injured conditions produced an increase in reflexive and affective pain- and anxiety-like behaviors. Moreover, activation of PIC CaMKIIa-expressing neurons during inflammatory pain conditions exacerbated hyperalgesia and decreased pain tolerance. However, Chemogenetic activation did not alter heat nociception via hot plate latency or body temperature. Conversely, inhibiting CaMKIIa-expressing neurons did not alter either sensory or affective pain-like behaviors in non-injured or under inflammatory pain conditions, but it did decrease body temperature and decreased hot plate latency. Our findings reveal that PIC CaMKIIa-expressing neurons are a critical hub for producing both sensory and affective pain-like behaviors and important for thermoregulatory processing. PERSPECTIVE: The present study reveals that activation of the posterior insula produces hyperalgesia and negative affect, and has a role in thermal tolerance and thermoregulation. These findings highlight the insula as a key player in contributing to the multidimensionality of pain.

Functional connectivity disruption of insular subregions in the cirrhotic patients with minimal hepatic encephalopathy

We investigated abnormal functional connectivity (FC) patterns of insular subregions in patients with minimal hepatic encephalopathy (MHE) and examined their relationships with cognitive dysfunction using resting-state functional magnetic resonance imaging (fMRI). We collected resting-state fMRI data in 54 patients with cirrhosis [20 with MHE and 34 without MHE (NHE)] and 25 healthy controls. After defining six subregions of insula, we mapped whole-brain FC of the insular subregions and identified FC differences through three groups. FC of the insular subregions was correlated against clinical parameters (including venous blood ammonia level, Child-Pugh score, and cognitive score). The discrimination performance between the MHE and NHE groups was evaluated by performing a classification analysis using the FC index. Across three groups, the observed FC differences involved four insular subregions, including the left-ventral anterior insula, left-dorsal anterior insula, right-dorsal anterior insula, and left-posterior insula (P < 0.05 with false discovery rate correction). Moreover, the FC of these four insular subregions progressively attenuated from NHE to MHE. In addition, hypoconnectivity of insular subregions was correlated with the poor neuropsychological performance and the evaluated blood ammonia levels in patients (P < 0.05 with Bonferroni correction). The FC of insular subregions yielded moderate discriminative value between the MHE and NHE groups (AUC = 0.696-0.809). FC disruption of insular subregions is related to worse cognitive performance in MHE. This study extended our understanding about the neurophysiology of MHE and may assist for its diagnosis.

Blunted Neurobehavioral Loss Anticipation Predicts Relapse to Stimulant Drug Use

BACKGROUND

Patients with stimulant use disorder experience high rates of relapse. While neurobehavioral mechanisms involved in initiating drug use have been studied extensively, less research has focused on relapse.

METHODS

To assess motivational processes involved in relapse and diagnosis, we acquired functional magnetic resonance imaging responses to nondrug (monetary) gains and losses in detoxified patients with stimulant use disorder (n = 68) and community control participants (n = 42). In a prospective multimodal design, we combined imaging of brain function, brain structure, and behavior to longitudinally track subsequent risk for relapse.

RESULTS

At the 6-month follow-up assessment, 27 patients remained abstinent, but 33 had relapsed. Patients with blunted anterior insula (AIns) activity during loss anticipation were more likely to relapse, an association that remained robust after controlling for potential confounds (i.e., craving, negative mood, years of use, age, and gender). Lower AIns activity during loss anticipation was associated with lower self-reported negative arousal to loss cues and slower behavioral responses to avoid losses, which also independently predicted relapse. Furthermore, AIns activity during loss anticipation was associated with the structural coherence of a tract connecting the AIns and the nucleus accumbens, as was functional connectivity between the AIns and nucleus accumbens during loss processing. However, these neurobehavioral responses did not differ between patients and control participants.

CONCLUSIONS

Taken together, the results of the current study show that neurobehavioral markers predicted relapse above and beyond conventional self-report measures, with a cross-validated accuracy of 72.7%. These findings offer convergent multimodal evidence that implicates blunted avoidance motivation in relapse to stimulant use and may therefore guide interventions targeting individuals who are most vulnerable to relapse.

Hyperechoic Area Under Insular Gliomas: A Potentially Hazardous Intraoperative Ultrasound Artifact

BACKGROUND

Intraoperative ultrasound (IOUS) images can be distorted by various artifacts. During surgeries for insular low-grade gliomas (LGGs), we repeatedly observed a distinct hyperechoic artifact adjacent to medial tumor borders, localized in brain regions with normal appearance on magnetic resonance imaging (MRI) that has not been reported before.

METHODS

We retrospectively evaluated saved 3-dimensional (3D) IOUS images of 20 patients harboring insular LGGs. Twelve patients were operated on between 2010 and 2015 using an older navigated 3D IOUS system. Additionally, 3D-IOUS images of 8 patients operated on between 2021 and 2023 using a new high-end 3D-IOUS system were evaluated. The investigated region was the area under medial tumor borders, which were defined using preoperative MRI.

RESULTS

In 17 out of 20 cases (85%), a distinct hyperechoic area adjacent to medial tumor borders localized in brain regions with normal appearance on preoperative MRI was found; in the remaining 3 cases the saved images were suboptimal and did not allow evaluation of the area under the medial tumor borders.

CONCLUSIONS

Although the causes of this bright artifact are unclear, we can hypothesize that the reverberation in between different parallel layers of white and gray matter localized under the insula could play a role in its appearance. Importantly, as this hyperechoic area was depicted already before any tumor resection, it may lead to erroneous conclusion that the tumor spreads more medially. Potential resection in this region may cause significant neurologic sequelae.

An "epileptic scent": Olfactory auras in tumor-related epilepsy

OBJECTIVES

To characterize a profile for patients with tumor-related epilepsy presenting olfactory auras.

MATERIALS AND METHODS

We conducted a monocentric, retrospective study on patients who underwent surgery in the Neurosurgery Unit of Udine University Hospital (Udine, Italy), between the 1st of January 2010 and the 1st of January 2019, for primary brain tumors (PBTs) involving the temporal lobe and the insula. All patients were affected by tumor-related epilepsy; the study group presented olfactory auras as well. We collected neuroradiological, neuropsychological and neurophysiological data from patients' medical charts.

RESULTS

The subtraction analysis of MRI data shows maximum lesion overlay in left olfactory cortex, left and right hippocampus, left amygdala, right rolandic operculum, right inferior frontal gyrus and right middle temporal gyrus. The presence of olfactory auras did not influence seizure outcome (p = 0.500) or tumor recurrence after surgery (p = 0.185). The type of auras (elementary vs. complex), also, did not influence seizure control (p = 0.222).

DISCUSSION

In presence of olfactory auras, anterior and mesial temporal regions are mainly involved, such as olfactory cortex, amygdala, and anterior hippocampus, together with right rolandic operculum, right inferior frontal gyrus and right middle temporal gyrus, suggesting their possible role in the genesis of olfactory auras. Post-surgical seizure outcome and disease relapse are not influenced by neither the presence nor the type of olfactory auras.

CONCLUSIONS

Olfactory auras are rare event, however they may be often underestimated by the patients and under-investigated by the clinicians, even when their occurrence can represent a useful localizing tool.

Stress and reward in the maternal brain of mothers with borderline personality disorder: a script-based fMRI study

Borderline personality disorder (BPD) is associated with altered neural activity in regions of salience and emotion regulation. An exaggerated sensitization to emotionally salient situations, increased experience of emotions, and dysfunctional regulative abilities could be reasons for increased distress also during parenting. Mothers with BPD tend to have less reciprocal mother-child interactions (MCI) and reveal altered cortisol and oxytocin reactivity in the interaction with their child, which could indicate altered processing of stress and reward. Here, we studied underlying neural mechanisms of disrupted MCI in BPD. Twenty-five mothers with BPD and 28 healthy mothers participated in a script-driven imagery functional magnetic resonance imaging (fMRI)-paradigm. Scripts described stressful or rewarding MCI with the own child, or situations in which the mother was alone. Mothers with BPD showed larger activities in the bilateral insula and anterior cingulate cortex (ACC) compared to healthy mothers during the imagination of MCI and non-MCI. Already in the precursory phase while listening to the scripts, a similar pattern emerged with stronger activity in the left anterior insula (AINS), but not in the ACC. This AINS activity correlated negatively with the quality of real-life MCI for mothers with BPD. Mothers with BPD reported lower affect and higher arousal. An exaggerated sensitization to different, emotionally salient situations together with dysfunctional emotion regulation abilities, as reflected by increased insula and ACC activity, might hinder sensitive maternal behavior in mothers with BPD. These results underline the importance for psychotherapeutic interventions to improve emotional hyperarousal and emotion regulation in patients with BPD, especially in affected mothers caring for young children.

Emotion dysregulation, impulsivity and anger rumination in borderline personality disorder: the role of amygdala and insula

Borderline Personality Disorder (BPD) is a severe mental disorder, characterized by deficits in emotion regulation, interpersonal dysfunctions, dissociation and impulsivity. Brain abnormalities have been generally explored; however, the specific contribution of different limbic structures to BPD symptomatology is not described. The aim of this study is to cover this gap, exploring functional and structural alterations of amygdala and insula and to highlight their contribution to neuropsychiatric symptoms. Twenty-eight BPD patients (23.7 ± 3.42 years; 6 M/22F) and twenty-eight matched healthy controls underwent a brain MR protocol (1.5 T, including a 3D T1-weighted sequence and resting-state fMRI) and a complete neuropsychiatric assessment. Volumetry, cortical thickness and functional connectivity of amygdala and insula were evaluated, along with correlations with the neuropsychiatric scales. BPD patients showed a lower cortical thickness of the left insula (p = 0.027) that negatively correlated with the Anger Rumination Scale (p = 0.019; r = - 0.450). A focused analysis on female patients showed a significant reduction of right amygdala volumes in BPD (p = 0.037), that correlate with Difficulties in Emotion Regulation Scale (p = 0.031; r =  - 0.415), Beck Depression Inventory (p = 0.009; r =  - 0.50) and Ruminative Response Scale (p = 0.045; r =  - 0.389). Reduced functional connectivity was found in BPD between amygdala and frontal pole, precuneus and temporal pole. This functional connectivity alterations correlated with Anger Rumination Scale (p = .009; r = - 0.491) and Barratt Impulsiveness Scale (p = 0.020; r = - 0.447). Amygdala and insula are altered in BPD patients, and these two limbic structures are implicated in specific neuropsychiatric symptoms, such as difficulty in emotion regulation, depression, anger and depressive rumination.

Neural correlates of risk taking in patients with obsessive-compulsive disorder during risky decision-making

BACKGROUND

The risk preference during decision-making and the neural substrates involved in patients with obsessive-compulsive disorder (OCD) remained unclear. The current study was designed to evaluate the risk-taking behaviors during decision-making and neural correlates in patients with OCD, thereby providing a deeper insight into their impaired decision-making function.

METHODS

Fifty-one patients with OCD and 50 healthy controls (HCs) were included in this study. All subjects underwent functional magnetic resonance imaging (fMRI) scans while completing the Balloon Analog Risk Task (BART). The behavior indicator and cognitive model parameter in BART, as well as the neural correlates of risk-taking behaviors were analyzed.

RESULTS

Compared to HCs, the OCD group performed a significantly higher level of risk-averse behaviors, and the cognitive model parameter revealed that patients with OCD tend to decrease their risk level after receiving negative feedbacks during BART. The fMRI results based on prespecified brain regions showed that the OCD group exhibited significantly decreased activation modulated by risk levels both in the left and right insula.

LIMITATIONS

The effect of medication in this study could not be completely ruled out, and it is difficult to temporally separate different states of decision-making in the BART.

CONCLUSIONS

Individuals with OCD exhibited a higher level of risk aversion during decision-making process, and the dysfunction of the insula may be the neural basis of the increased risk aversion in OCD. These findings provide further insights into the mechanism of risk aversion and impaired decision-making function in individuals with OCD.

Food go/no-go training alters neural circuits for food evaluation for appetite reduction

Food go/no-go training has been traditionally categorized as a type of inhibitory training that decreases the desire for high-calorie food consumption. This training requires participants to either respond or withhold their responses to presented items with go cues or food items with no-go cues, respectively. Recent findings have suggested that this training may devalue food items associated with no-go cues instead of facilitating inhibitory control, leading to reduced food consumption. We thus hypothesized that food go/no-go training would alter the brain response to food items with no-go cues in food evaluation regions. To examine this hypothesis, we conducted a repeated measures functional magnetic resonance imaging using food images in healthy participants, who underwent 3 weeks of food go/no-go training (n = 26) using high- and low-calorie food items paired with no-go cues (no-go food) and go cues (go food), respectively, and control training (n = 24). The food go/no-go training reduced the ratings for the desire to eat no-go foods and increased the ratings for go foods. The reduction in no-go food rating was positively associated with a decrease in daily snack intake. The neural responses in the food evaluation regions increased for go foods. Moreover, the functional connectivity of those regions was altered. The food go/no-go training did not decrease impulsivity traits or increase restrained eating, which are associated with inhibitory control. Overall, food go/no-go training influenced the brain regions associated with food evaluation, thus devaluating no-go foods and reducing the daily snack intake. Accordingly, food go/no-go training could promote healthier food choices.

Top-down control of vestibular inputs by the dorsolateral prefrontal cortex

The vestibular apparatus provides spatial information on the position of the head in space and with respect to gravity. Low-frequency sinusoidal galvanic vestibular stimulation (sGVS), a means of selectively changing the firing of vestibular afferents, induces a frequency-dependent perception of sway and, in some individuals, induces nausea. Given that vestibular afferents project to the insular cortex-which forms part of the vestibular cortex-and that the insula receives inputs from the dorsolateral prefrontal cortex (dlPFC), we tested the hypothesis that electrical stimulation of the dlPFC can modulate vestibular inputs. Sinusoidal electrical stimulation (± 2 mA, 0.08 Hz, 100 cycles) was delivered via surface electrodes over (1) the mastoid processes alone (sGVS), (2) electroencephalogram (EEG) site F4 (right dlPFC) and the nasion or (3) to each site concurrently (sGVS + dlPFC) in 23 participants. The same stimulation protocol was used in a separate study to investigate EEG site F3 (left dlPFC) instead of F4 in 13 participants. During sGVS, all participants reported perceptions of sway and 13 participants also reported nausea, neither sensation of which occurred as a result of dlPFC stimulation. Interestingly, when sGVS and dlPFC stimulations were delivered concurrently, vestibular perceptions and sensations of nausea were almost completely abolished. We conclude that the dlPFC provides top-down control of vestibular inputs and further suggests that dlPFC stimulation may provide a novel means of controlling nausea.

Altered functional connectivity in a sensorimotor-insular network during spontaneous migraine attacks: A resting-state FMRI study

BACKGROUND

Previous functional magnetic resonance imaging studies have identified brain-connectivity alterations across multiple regions in people with migraine when compared to healthy controls. Few studies have focused on such changes throughout the different phases of the migraine cycle. We aimed to investigate functional connectivity during spontaneous occurring episodic migraine attacks, in comparison to interictal periods.

METHODS

Eleven women with episodic migraine without aura underwent two sessions of resting-state fMRI, during and outside of a spontaneous migraine attack. Functional connectivity changes were assessed across canonical resting-state networks, identified by independent component analysis. Significantly altered connectivity was correlated with migraine attack symptoms.

RESULTS

Decreased functional connectivity between subregions of the sensorimotor network (specifically, the primary somatosensory and motor cortices) and the posterior insula, bilaterally, was found during attacks. In both sessions, the functional connectivity between these regions was lower in patients who usually suffered longer attacks.

DISCUSSION

The sensorimotor and insular regions are involved in nociceptive, autonomic, and somatosensory processing so the finding of reduced connectivity between these structures within a migraine attack is likely associated to the perception of pain and the heighten sensitivity to stimuli experienced in this disorder.

Subjective states induced by intracranial electrical stimulation matches the cytoarchitectonic organization of the human insula

Functions of the human insula have been explored extensively with neuroimaging methods and intracranial electrical stimulation studies that have highlighted a functional segregation across its subregions. A recently developed cytoarchitectonic map of the human insula has also segregated this brain region into various areas. Our knowledge of the functional organization of this brain region at the level of these fine-parceled microstructural areas remains only partially understood. We address this gap of knowledge by applying a multimodal approach linking direct electrical stimulation and task-evoked intracranial EEG recordings with microstructural subdivisions of the human insular cortex. In 17 neurosurgical patients with 142 implanted electrodes, stimulation of 40 % of the sites induced a reportable change in the conscious experience of the subjects in visceral/autonomic, anxiety, taste/olfactory, pain/temperature as well as somatosensory domains. These subjective responses showed a topographical allocation to microstructural areas defined by probabilistic cytoarchitectonic parcellation maps of the human insula. We found the pain and thermal responses to be located in areas lg2/ld2, while non-painful/non-thermal somatosensory responses corresponded to area ld3 and visceroceptive responses to area Id6. Lastly, the stimulation of area Id7 in the dorsal anterior insula, failed to induce reportable changes to subjective experience even though intracranial EEG recordings from this region captured significant time-locked high-frequency activity (HFA). Our results provide a multimodal map of functional subdivisions within the human insular cortex at the individual brain basis and characterize their anatomical association with fine-grained cytoarchitectonic parcellations of this brain structure.

How does feeling pain look like in depression: A review of functional neuroimaging studies

INTRODUCTION

Major Depression Disorder (MDD) and pain appear to be reciprocal risk factors and sharing common neuroanatomical pathways and biological substrates. However, the role of MDD on pain processing remains still unclear. Therefore, this review aims to focus on the effect of depression on pain anticipation, and perception, before and after treatment, through functional magnetic resonance imaging (fMRI).

METHODS

A bibliographic search was conducted on PubMed, Scopus and Web of Science, looking for fMRI studies exploring pain processing in MDD patients.

RESULTS

Amongst the 602 studies retrieved, 12 met the inclusion criteria. In terms of pain perception, studies evidenced that MDD patients generally presented increased activation in brain regions within the prefrontal cortex, insula and in the limbic system (such as amygdala, hippocampus) and occipital cortex. The studies investigating the effect of antidepressant treatment evidenced a reduced activation in areas such as insula, anterior cingulate, and prefrontal cortices. In terms of pain anticipation, contrasting results were evidenced in MDD patients, which presented both increased and decreased activity in the prefrontal cortex, the insula and the temporal lobe, alongside with increased activity in the anterior cingulate cortex, the frontal gyrus and occipital lobes.

LIMITATIONS

The small number of included studies, the heterogeneous approaches of the studies might limit the conclusions of this review.

CONCLUSIONS

Acute pain processing in MDD patients seems to involve numerous and different brain areas. However, more specific fMRI studies with a more homogeneous population and rigorous approach should be conducted to better highlight the effect of depression on pain processing.

Bidirectional relationship between insular grey matter volume and alexithymia: Evidence from a longitudinal study

BACKGROUND

The insula is considered to be involved in emotional cognitive processes, and may be structurally altered in people with alexithymia. However, it remains unclear how the relationship between the insula and alexithymia changes over time. This study aimed to investigate whether alexithymia has longitudinal relationship with the insular structure.

METHODS

Having processed structural MRI data via FreeSurfer, the insula was divided into five sub-regions, and the Toronto Alexithymia Scale was administered to assess alexithymia in the general population. Subsequently, we established the latent change score models between insular sub-regions and the alexithymia (N = 252).

RESULTS

The TAS-20 mean value of the sample at Time 1 was not significantly different by sex (t = -0.993, df = 250, p = 0.321), while the TAS-20 mean value at Time 2 was slightly different by sex (t = 2.025, df = 250, p = 0.044). Most insular grey matter volumes at Time 1 and Time 2 were significantly associated with TAS-20 at Time 2. The baseline alexithymia and insular grey matter volume positively predicted the other's rate of change between Time 1 and Time 2 in a bidirectional way.

LIMITATIONS

This study had a limited number of measurement time points, potential bias due to smaller sample sizes and gender imbalance, as well as the potential for inaccuracy in the self-report measure of alexithymia.

CONCLUSIONS

Time-lagged alexithymia changes and insular grey matter volume changes occur in coupled manner over time, which might improve our understanding of the neurological underpinnings of alexithymia, and shed light on clinical and psychological treatment for alexithymia.

Still a "hidden island"? The rodent insular cortex in drug seeking, reward, and risk

The insular cortex (IC) is implicated in risky decision making and drug-seeking behaviors, in a manner dissociable from natural reward seeking. However, evidence from rodent studies of motivated behaviors suggests that the role of the IC is not always consistent across procedures. Moreover, there is evidence of dissociation of function between posterior (pIC) and anterior (aIC) subregions in these behaviors. Under which circumstances, and by which mechanisms, these IC subregions are recruited to regulate motivated behaviors remains unclear. Here, we discuss evidence of rodent pIC and aIC function across drug-related behaviors, natural reward seeking, and decision making under risk and highlight procedural differences that may account for seemingly conflicting findings. Although gaps in the literature persist, we hypothesize that IC activity is broadly important for selection of appropriate behaviors based on learned action-outcome contingencies and that associated risk is sufficient, but not necessary, to recruit the aIC in reward seeking without involving the pIC.

The neuropsychology and neuroanatomy of reduplicative paramnesia

Reduplicative paramnesia refers to the delusional belief that there are identical places in different locations. In this case-control study we investigated the clinical, phenomenological, neuropsychological and neuroanatomical data of eleven patients with reduplicative paramnesia and compared them against a control group of eleven patients with severe spatial disorientation without signs of reduplicative paramnesia. We show that most patients with reduplicative paramnesia report that a current place is reduplicated and/or relocated to an other familiar place. Patients with reduplicative paramnesia show a higher prevalence of deficits in the executive functions compared to the control patients, while mnestic and visuo-spatial deficits were both frequent in patients with reduplicative paramnesia and the control group. Patients with reduplicative paramnesia mostly suffer from right hemispheric lesions with a maximal overlap in the dorsolateral prefrontal cortex. Using lesion network mapping we show that lesions causing reduplicative paramnesia are connected to bilateral anterior insula and the right cingulate cortex. We argue that patients with reduplicative paramnesia fail to integrate the actual context with visuo-spatial memories and personal relevant emotional information due to a disruption of the neural network within the anterior temporal lobe, the cingulate cortex and the anterior insula. Also patients with reduplicative paramnesia are not able to resolve this conflict due to the lesion of the dorsolateral prefrontal cortex and executive dysfunction.

Gross anatomical variations of the insular cortex in first-episode schizophrenia

BACKGROUND

Magnetic resonance imaging (MRI) studies have revealed gray matter reductions in the insular cortex of schizophrenia patients. Despite large inter-individual anatomical variations in the insular gyri of human brains, the gross anatomical features of the insular cortex and their relationships with clinical characteristics remain largely unknown in schizophrenia.

METHODS

The present MRI study investigated variations in the insular gross anatomy (i.e., the development and split patterns of each gyrus and gyrus numbers) and their relationships with clinical variables and insular gray matter volumes in 66 patients with first-episode schizophrenia (FE-Sz) and 66 age- and sex-matched healthy controls.

RESULTS

The FE-Sz group had a significantly larger number of insular gyri bilaterally with well-developed accessory, middle short, and posterior long insular gyri than the control group, and this was associated with a younger onset age and severe positive symptoms. The split patterns of major insular gyri did not significantly differ between the groups. The FE-Sz group was also characterized by a smaller gray matter volume in the insular cortex than the control group; however, this was not associated with the insular gross anatomy or clinical characteristics.

CONCLUSION

As the insular gyral organization reflects brain development during mid to late gestation, the gross anatomical features of the insular cortex in schizophrenia, which were independent of gray matter volumes, may be used as early neurodevelopmental abnormality markers for the illness.

Targeting the insula with transcranial direct current stimulation; A simulation study

Insula is considered an important region of the brain in the generation and maintenance of a wide range of psychiatric symptoms, possibly due to being key in fundamental functions such as interoception and cognition in general. Investigating the possibility of targeting this area using non-invasive brain stimulation techniques can open new possibilities to probe the normal and abnormal functioning of the brain and potentially new treatment protocols to alleviate symptoms of different psychiatric disorders. In the current study, COMETS2, a MATLAB based toolbox was used to simulate the magnitude of the current density and electric field in the brain caused by different transcranial direct current stimulation (tDCS) protocols to find an optimum montage to target the insula and its 6 subregions for three different current intensities, namely 2, 3, and 4 mA. Frontal and occipital regions were found to be optimal candidate regions.. The results of the current study showed that it is viable to reach the insula and its individual subregions using tDCS.

Higher emotional granularity relates to greater inferior frontal cortex cortical thickness in healthy, older adults

Individuals with high emotional granularity make fine-grained distinctions between their emotional experiences. To have greater emotional granularity, one must acquire rich conceptual knowledge of emotions and use this knowledge in a controlled and nuanced way. In the brain, the neural correlates of emotional granularity are not well understood. While the anterior temporal lobes, angular gyri, and connected systems represent conceptual knowledge of emotions, inhibitory networks with hubs in the inferior frontal cortex (i.e., posterior inferior frontal gyrus, lateral orbitofrontal cortex, and dorsal anterior insula) guide the selection of this knowledge during emotions. We investigated the structural neuroanatomical correlates of emotional granularity in 58 healthy, older adults (ages 62-84 years), who have had a lifetime to accrue and deploy their conceptual knowledge of emotions. Participants reported on their daily experience of 13 emotions for 8 weeks and underwent structural magnetic resonance imaging. We computed intraclass correlation coefficients across daily emotional experience surveys (45 surveys on average per participant) to quantify each participant's overall emotional granularity. Surface-based morphometry analyses revealed higher overall emotional granularity related to greater cortical thickness in inferior frontal cortex (pFWE < 0.05) in bilateral clusters in the lateral orbitofrontal cortex and extending into the left dorsal anterior insula. Overall emotional granularity was not associated with cortical thickness in the anterior temporal lobes or angular gyri. These findings suggest individual differences in emotional granularity relate to variability in the structural neuroanatomy of the inferior frontal cortex, an area that supports the controlled selection of conceptual knowledge during emotional experiences.

Hemispheric contributions toward interoception and emotion recognition in left-vs right-semantic dementia

BACKGROUND

The hemispheric contributions toward interoception, the perception of internal bodily cues, and emotion recognition remains unclear. Semantic dementia cases with either left-dominant (i.e., left-SD) or right-dominant (i.e., right-SD) anterior temporal lobe atrophy experience emotion recognition difficulties, however, little is known about interoception in these syndromes. Here, we hypothesised that right-SD would show worse interoception and emotion recognition due to right-dominant atrophy.

METHODS

Thirty-five participants (8 left-SD; 6 right-SD; 21 controls) completed a monitoring task. Participants pressed a button when they: (1) felt their heartbeat, without pulse measurement (Interoception); or (2) heard a recorded heartbeat (Exteroception-control). Simultaneous ECG was recorded. Accuracy was calculated by comparing the event frequency (i.e., heartbeat or sound) to response frequency. Emotion recognition was assessed via the Facial Affect Selection Task. Voxel-based morphometry analyses identified neural correlates of interoception and emotion recognition.

RESULTS

Right-SD showed worse interoception than controls and left-SD (both p's < 0.001). Both patient groups showed worse emotion recognition than controls (right-SD: p < .001; left-SD: p = .018), and right-SD showed worse emotion recognition than left-SD (p = .003). Regression analyses revealed that worse emotion recognition was predicted by right-SD (p = .002), left-SD (p = .005), and impaired interoception (p = .004). Interoception and emotion were associated with the integrity of right-lateralised structures including the insula, temporal pole, thalamus, superior temporal gyrus, and hippocampus.

CONCLUSION

Our study provides the first evidence for impaired interoception in right-SD, suggesting that impaired emotion recognition in this syndrome is driven by inaccurate internal monitoring. Further we identified a common neurobiological basis for interoception and emotion in the right hemisphere.

Reduced anterior insular cortex volume in male heroin addicts: a postmortem study

We and others have observed reduced volumes of brain regions, including the nucleus accumbens, globus pallidus, hypothalamus, and habenula in opioid addiction. Notably, the insular cortex has been under increasing study in addiction, and a smaller anterior insula has been found in alcohol-addicted cases. Here, we have investigated whether similar effects occur in heroin addicts compared to healthy controls. Volumes of the anterior and posterior insula in heroin addicts (n = 14) and controls (n = 13) were assessed by morphometry of Nissl-myelin-stained serial whole-brain coronal sections. The mean relative volume of the anterior insular cortex was smaller than in non-addicted controls (3010 ± 614 *10-6 versus 3970 ± 1306 *10-6; p = 0.021). However, no significant differences in neuronal cell counts were observed. Therefore, the observed volume reduction appears to be a consequence of damaged connecting structures such as neuropil and glial cells. The findings were not confounded by age or duration of autolysis. Our results provide further evidence of structural deficits in key hubs of the addiction circuitry in heroin-dependent individuals and warrant further research in this area.

Cerebral cortical thinning in brain regions involved in emotional regulation relates to persistent symptoms in subjects with posttraumatic stress disorder

A considerable proportion of individuals exposed to trauma experience chronic and persistent posttraumatic stress disorder (PTSD). However, the specific brain and clinical features that render trauma-exposed individuals more susceptible to enduring symptoms remain elusive. This study investigated 112 trauma-exposed participants who had been diagnosed with PTSD and 112 demographically-matched healthy controls. Trauma-exposed participants were classified into those with current PTSD (persistent PTSD, n = 78) and those without (remitted PTSD, n = 34). Cortical thickness analysis was performed to discern group-specific brain structural characteristics. Coping strategies and resilience levels, assessed as clinical attributes, were compared across the groups. The persistent PTSD group displayed cortical thinning in the superior frontal cortex (SFC), insula, superior temporal cortex, dorsolateral prefrontal cortex, superior parietal cortex, and precuneus, relative to the remitted PTSD and control groups. Cortical thinning in the SFC was associated with increased utilization of maladaptive coping strategies, while diminished thickness in the insula correlated with lower resilience levels among trauma-exposed individuals. These findings imply that cortical thinning in brain regions related to coping strategy and resilience plays a vital role in the persistence of PTSD symptoms.

Efficacy of insula deep repetitive transcranial magnetic stimulation combined with varenicline for smoking cessation: A randomized, double-blind, sham controlled trial

BACKGROUND

Current smoking cessation treatments are limited in terms of efficacy, particularly with regards to long term abstinence. There is a large amount of evidence implicating the insula in nicotine addiction.

OBJECTIVE

To examine the efficacy of bilateral repetitive transcranial magnetic stimulation (rTMS) directed to the insular cortex with the H11 coil, relative to sham stimulation, on smoking abstinence and smoking outcomes in smokers who are receiving standard varenicline treatment.

METHODS

This randomized, double-blind, sham controlled trial recruited 42 participants who were randomized to receive either active (n = 24) or sham (n = 18) high frequency rTMS directed to the insula (4 weeks), while receiving varenicline treatment (12 weeks). The primary outcome was 7-day point prevalence abstinence at the end of 12 weeks.

RESULTS

Smokers in the active group had significantly higher abstinence rates than those in the sham group (82.4% vs. 30.7%, p = 0.013) at the end of treatment (Week 12). Secondary outcome measures of abstinence rate at the end of rTMS treatment (Week 4), abstinence rate at 6 months, and smoking outcomes (e.g., craving, withdrawal) showed no significant differences between groups. No differences were found in adverse events reported between the groups.

CONCLUSION

This study provides evidence of the potential benefit of having a combined treatment for smoking cessation using insula rTMS with the H11 coil and varenicline. Maintenance rTMS sessions and continuation of varenicline for those in abstinence may induce longer-term effects and should be considered in future studies.

Insula neuroanatomical networks predict interoceptive awareness

Interoceptive awareness (IA), the subjective and conscious perception of visceral and physiological signals from the body, has been associated with functions of cortical and subcortical neural systems involved in emotion control, mood and anxiety disorders. We recently hypothesized that IA and its contributions to mental health are realized by a brain interoception network (BIN) linking brain regions that receive ascending interoceptive information from the brainstem, such as the amygdala, insula and anterior cingulate cortex (ACC). However, little evidence exists to support this hypothesis. In order to test this hypothesis, we used a publicly available dataset that contained both anatomical neuroimaging data and an objective measure of IA assessed with a heartbeat detection task. Whole-brain Voxel-Based Morphometry (VBM) was used to investigate the association of IA with gray matter volume (GMV) and the structural covariance network (SCN) of the amygdala, insula and ACC. The relationship between IA and mental health was investigated with questionnaires that assessed depressive symptoms and anxiety. We found a positive correlation between IA and state anxiety, but not with depressive symptoms. In the VBM analysis, only the GMV of the left anterior insula showed a positive association with IA. A similar association was observed between the parcellated GMV of the left dorsal agranular insula, located in the anterior insula, and IA. The SCN linking the right dorsal agranular insula with the left dorsal agranular insula and left hyper-granular insula were positively correlated with IA. No association between GMV or SCN and depressive symptoms or anxiety were observed. These findings revealed a previously unknown association between IA, insula volume and intra-insula SCNs. These results may support development of non-invasive neuroimaging interventions, e.g., neurofeedback, seeking to improve IA and to prevent development of mental health problems, such anxiety disorders.

Functional characterization of macaque insula using task-based and resting-state fMRI

Neurophysiological investigations over the past decades have demonstrated the involvement of the primate insula in a wide array of sensory, cognitive, affective and regulatory functions, yet the complex functional organization of the insula remains unclear. Here we examined to what extent non-invasive task-based and resting-state fMRI provides support for functional specialization and integration of sensory and motor information in the macaque insula. Task-based fMRI experiments suggested a functional specialization related to processing of ingestive/taste/distaste information in anterior insula, grasping-related sensorimotor responses in middle insula and vestibular information in posterior insula. Visual stimuli depicting social information involving conspecific`s lip-smacking gestures yielded responses in middle and anterior portions of dorsal and ventral insula, overlapping partially with the sensorimotor and ingestive/taste/distaste fields. Functional specialization/integration of the insula was further corroborated by seed-based whole brain resting-state analyses, showing distinct functional connectivity gradients across the anterio-posterior extent of both dorsal and ventral insula. Posterior insula showed functional correlations in particular with vestibular/optic flow network regions, mid-dorsal insula with vestibular/optic flow as well as parieto-frontal regions of the sensorimotor grasping network, mid-ventral insula with social/affiliative network regions in temporal, cingulate and prefrontal cortices and anterior insula with taste and mouth motor networks including premotor and frontal opercular regions.

Proteomic Profiling Reveals Specific Molecular Hallmarks of the Pig Claustrum

The present study, employing a comparative proteomic approach, analyzes the protein profile of pig claustrum (CLA), putamen (PU), and insula (IN). Pig brain is an interesting model whose key translational features are its similarities with cortical and subcortical structures of human brain. A greater difference in protein spot expression was observed in CLA vs PU as compared to CLA vs IN. The deregulated proteins identified in CLA resulted to be deeply implicated in neurodegenerative (i.e., sirtuin 2, protein disulfide-isomerase 3, transketolase) and psychiatric (i.e., copine 3 and myelin basic protein) disorders in humans. Metascape analysis of differentially expressed proteins in CLA vs PU comparison suggested activation of the α-synuclein pathway and L1 recycling pathway corroborating the involvement of these anatomical structures in neurodegenerative diseases. The expression of calcium/calmodulin-dependent protein kinase and dihydropyrimidinase like 2, which are linked to these pathways, was validated using western blot analysis. Moreover, the protein data set of CLA vs PU comparison was analyzed by Ingenuity Pathways Analysis to obtain a prediction of most significant canonical pathways, upstream regulators, human diseases, and biological functions. Interestingly, inhibition of presenilin 1 (PSEN1) upstream regulator and activation of endocannabinoid neuronal synapse pathway were observed. In conclusion, this is the first study presenting an extensive proteomic analysis of pig CLA in comparison with adjacent areas, IN and PUT. These results reinforce the common origin of CLA and IN and suggest an interesting involvement of CLA in endocannabinoid circuitry, neurodegenerative, and psychiatric disorders in humans.

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.

Higher body weight-dependent neural activation during reward processing

Obesity is associated with alterations in brain structure and function, particularly in areas related to reward processing. Although brain structural investigations have demonstrated a continuous association between higher body weight and reduced gray matter in well-powered samples, functional neuroimaging studies have typically only contrasted individuals from the normal weight and obese body mass index (BMI) ranges with modest sample sizes. It remains unclear, whether the commonly found hyperresponsiveness of the reward circuit can (a) be replicated in well-powered studies and (b) be found as a function of higher body weight even below the threshold of clinical obesity. 383 adults across the weight spectrum underwent functional magnetic resonance imaging during a common card-guessing paradigm simulating monetary reward. Multiple regression was used to investigate the association of BMI and neural activation in the reward circuit. In addition, a one-way ANOVA model comparing three weight groups (normal weight, overweight, obese) was calculated. Higher BMI was associated with higher reward response in the bilateral insula. This association could no longer be found when participants with obesity were excluded from the analysis. The ANOVA revealed higher activation in obese vs. lean, but no difference between lean and overweight participants. The overactivation of reward-related brain areas in obesity is a consistent finding that can be replicated in large samples. In contrast to brain structural aberrations associated with higher body weight, the neurofunctional underpinnings of reward processing in the insula appear to be more pronounced in the higher body weight range.

The influence of sex steroid treatment on insular connectivity in gender dysphoria

BACKGROUND

Sex-specific differences in brain connectivity were found in various neuroimaging studies, though little is known about sex steroid effects on insular functioning. Based on well-characterized sex differences in emotion regulation, interoception and higher-level cognition, gender-dysphoric individuals receiving gender-affirming hormone therapy represent an interesting cohort to investigate how sex hormones might influence insular connectivity and related brain functions.

METHODS

To analyze the potential effect of sex steroids on insular connectivity at rest, 11 transgender women, 14 transgender men, 20 cisgender women, and 11 cisgender men were recruited. All participants underwent two magnetic resonance imaging sessions involving resting-state acquisitions separated by a median time period of 4.5 months and also completed the Bermond-Vorst alexithymia questionnaire at the initial and final examination. Between scans, transgender subjects received gender-affirming hormone therapy.

RESULTS

A seed based functional connectivity analysis revealed a significant 2-way interaction effect of group-by-time between right insula, cingulum, left middle frontal gyrus and left angular gyrus. Post-hoc tests demonstrated an increase in connectivity for transgender women when compared to cisgender men. Furthermore, spectral dynamic causal modelling showed reduced effective connectivity from the posterior cingulum and left angular gyrus to the left middle frontal gyrus as well as from the right insula to the left middle frontal gyrus. Alexithymia changes were found after gender-affirming hormone therapy for transgender women in both fantasizing and identifying.

CONCLUSION

These findings suggest a considerable influence of estrogen administration and androgen suppression on brain networks implicated in interoception, own-body perception and higher-level cognition.

Using pre-surgical suspicion to guide insula implantation strategy

Rationale

Insular epilepsy can be a challenging diagnosis due to overlapping semiology and scalp EEG findings with frontal, temporal, and parietal lobe epilepsies. Stereotactic electroencephalography (sEEG) provides an opportunity to better localize seizure onset. The possibility of improved localization is balanced by implantation risk in this vascularly rich anatomic region. We review both safety and pre-implantation factors involved in insular electrode placement across four years at an academic medical center.

Methods

Presurgical data, operative reports, and invasive EEG summaries were retrospectively reviewed for patients undergoing invasive epilepsy monitoring on the insula from 2016 through 2019. EEG reports were reviewed to record the presence of insula ictal and interictal involvement. We recorded which presurgical findings suggested insular involvement (insula lesion on MRI, insula changes on PET/SPECT/scalp EEG, characteristic semiology, or history of failed anterior temporal lobectomy). The likelihood of pre-sEEG insular onset was categorized as low suspicion if no presurgical findings were present ("rule out"), moderate suspicion if one finding was present, and high suspicion if two or more findings were present.

Results

76 patients received 189 insular electrodes as part of their implantation strategy for 79 surgical cases. Seven patients (8.9%) had insular ictal onset. One clinically significant complication (left hemiparesis) occurred in a patient with moderate suspicion for insular onset. There were 38 low suspicion cases, 36 moderate suspicion cases, and 5 high suspicion cases for pre-sEEG insula ictal onset. Two low suspicion (5.3%), three moderate suspicion (8.6%), and two high suspicion (40%) cases had insular ictal onset.

Conclusions

The insula can safely receive sEEG. Having two or more presurgical factors indicating insular onset is a strong, albeit incomplete, predictor of insular seizure onset. Using pre-implantation clinical findings can offer clinicians predictive value for targeting the insula during invasive EEG monitoring.

Modulatory effects of transcranial direct current stimulation of right insula on compassion motivation

Background

Compassion motivation is associated with increased heart rate variability (HRV), reflecting a calm and self-soothing physiological state. Recent work, however, suggests that this association is dynamic for the specific components of compassion.

Objectives

The present study adopted anodal transcranial direct current stimulation (tDCS) targeting the right insula to see whether this would modulate the sensitivity to suffering and the commitment to engage in helpful actions (i.e., the components of compassion motivation).

Method

Ninety-seven healthy individuals underwent 15-min anodal or sham tDCS over the frontotemporal lobe, while watching a video inducing empathic sensitivity and performing a Redistribution Game. Tonic and phasic HRV, dispositional traits, and momentary affects were assessed.

Results

Compared to sham condition, anodal stimulation favored significant i) HRV reductions during the video and HRV increases during the Redistribution Game; ii) decreases in self-reported levels of negative affect and increases in positive affect during task when the latter was preceded by the video, without influencing altruistic behavior.

Conclusions

Anodal tDCS over the right insula may modulate the engagement phase of compassion by intensifying the psychophysiological sensitivity to signals of distress and protecting from being subjectively overwhelmed by it.

A Novel Insular/Orbital-Prelimbic Circuit That Prevents Persistent Avoidance in a Rodent Model of Compulsive Behavior

BACKGROUND

A common symptom of obsessive-compulsive disorder is the persistent avoidance of cues incorrectly associated with negative outcomes. This maladaptation becomes increasingly evident as subjects fail to respond to extinction-based treatments such as exposure-with-response prevention therapy. While previous studies have highlighted the role of the insular-orbital cortex in fine-tuning avoidance-based decisions, little is known about the projections from this area that might modulate compulsive-like avoidance.

METHODS

Here, we used anatomical tract-tracing, single-unit recording, and optogenetics to characterize the projections from the insular-orbital cortex. To model exposure-with-response prevention and persistent avoidance in rats, we used the platform-mediated avoidance task followed by extinction-with-response prevention training.

RESULTS

Using tract-tracing and unit recording, we found that projections from the agranular insular/lateral orbital (AI/LO) cortex to the prefrontal cortex predominantly target the rostral portion of the prelimbic (rPL) cortex and excite rPL neurons. Photoinhibiting this projection induced persistent avoidance after extinction-with-response prevention training, an effect that was still present 1 week later. Consistent with this, photoexcitation of this projection prevented persistent avoidance in overtrained rats. This projection to rPL appears to be key for AI/LO's effects, considering that there was no effect of photoinhibiting AI/LO projections to the ventral striatum or basolateral amygdala.

CONCLUSIONS

Our findings suggest that projections from the AI/LO to the rPL decreases the likelihood of avoidance behavior following extinction. In humans, this connectivity may share some homology of projections from lateral prefrontal cortices (i.e., ventrolateral prefrontal cortex, orbitofrontal cortex, and insula) to other prefrontal areas and the anterior cingulate cortex, suggesting that reduced activity in these pathways may contribute to obsessive-compulsive disorder.

Structural connectivity of an interoception network in schizophrenia

Interoception refers to the processing, integration, and interpretation of bodily signals by the brain. Interoception is key to not only basic survival, but also motivational and affective functioning. There is emerging evidence suggesting altered interoception in schizophrenia, but few studies have explored potential neural underpinnings. The current study aims to investigate the anatomical connectivity of a previously identified interoception network in individuals with schizophrenia, and the relationship between network structural connectivity and both emotional functioning and clinical symptoms. Thirty-five participants with schizophrenia (SZ) and 36 healthy control participants (HC) underwent diffusion tensor imaging (DTI) and performed tasks measuring emotional functioning. Probabilistic tractography was used to identify white matter tracts connecting key hubs in an interoception network. Microstructural integrity of these tracts was compared across groups and correlated with measures of emotional functioning and symptom severity. Compared with HC, SZ exhibited altered structural connectivity in the interoception network. In HC, the structural connectivity of the network was significantly correlated with emotion recognition, supporting a link between the interoception network and emotional functioning. However, this correlation was much weaker in SZ. These findings suggest that altered interoception may have implications for illness mechanisms of schizophrenia, especially in relation to emotional deficits.

The insula mediates the effects of glucocorticoids in anxiety

Increased activity in the insula has been consistently reported to be associated with anxiety and anxiety-related disorders. However, little is known on how the insula regulates anxiety. The present study aims at determining the role of the insula on the effects of glucocorticoids in anxiety. A combination of pharmacological manipulations, including blockade of adrenal GC synthesis by metyrapone and intra-insular microinjections of corticosterone, corticosterone-BSA, mineralocorticoid receptor (MR) antagonist spironolactone and glucocorticoid receptor (GR) antagonist mifepristone, were used to assess the short-term (5 min) effects of intra-insular corticosterone in two anxiety-like behaviors in male Sprague-Dawley rats. The elevated plus maze (EPM) and Novelty Suppressed Feeding (hyponeophagia) were utilized. We found that corticosterone in the insula is sufficient to prevent the anxiolytic effects corticosterone synthesis blockade in anxiety, and that intra-insular corticosterone has anxiolytic or anxiogenic effects depending on the amount of corticosterone microinjected, without affecting the HPA axis. Glucocorticoid anxiolytic effects in the insula are mediated by MRs, while its anxiogenic effects are dependent on a mifepristone-sensitive membrane-bound mechanism. Anxiety appears to be modulated at the insula through a competition between fast MR-dependent anxiolytic and membrane-associated mifepristone-sensitive anxiogenic signaling pathways that orchestrate the behavioral response to stress and determines the resulting level of anxiety.

Anterior insula and dorsal anterior cingulate cortex as a hub of self-regulation: combining activation likelihood estimation meta-analysis and meta-analytic connectivity modeling analysis

Self-regulation, which is an individual's ability to control their emotions and behaviors in pursuit of goals, is a complex cognitive function that relies on distributed brain networks. Here, we used activation likelihood estimation (ALE) to conduct two large-scale meta-analyses of brain imaging studies of emotional regulation and behavioral regulation. We used single analysis of ALE to identify brain activation regions associated with behavioral regulation and emotion regulation. The conjunction results of the contrast analysis of the two domains showed that the crucial brain regions of dorsal anterior cingulate cortex (dACC), bilateral anterior insula (AI), and right inferior parietal lobule (IPL) are nested within the brain areas of the two regulation domains at the spatial and functional level. In addition, we assessed the coactivation pattern of the four common regions using meta-analytic connectivity modeling (MACM). The coactivation brain patterns based on the dACC and bilateral AI overlapped with the two regulation brain maps in a high proportion. Furthermore, the functional characters of the identified common regions were reverse-inferenced using the BrainMap database. Collectively, these results indicate that the brain regions of dACC and bilateral AI, playing a crucial role as a hub to other brain regions and networks by effective connectivity in self-regulation, are spatially nested in the brain network of behavioral regulation and emotion regulation.