Insular cortex

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.

Neurobiological Features of Posttraumatic Stress Disorder (PTSD) and Their Role in Understanding Adaptive Behavior and Stress Resilience

Posttraumatic stress disorder (PTSD) has been impacting the functioning of a large number of people in military activities and victims of violence for many generations. However, investments in research aiming to understand the neurobiological aspects of the disorder started relatively late, around the last third of the 20th century. The development of neuroimaging methods has greatly supported further understanding of the structural and functional changes in the re-organization processes of brains with PTSD. This helps to better explain the severity and evolution of behavioral symptoms, and opens the possibilities for identifying individual preexisting structural characteristics that could increase symptom severity and the risk of development. Here, we review the advances in neuroanatomical research on these adaptations in PTSD and discuss how those modifications in prefrontal and anterior cingulate circuitry impact the severity and development of the disorder, detaching the research from an amygdalocentric perspective. In addition, we investigate existing and contradictory evidence regarding the preexisting neurobiological features found mostly in twin studies and voxel-based morphometry (VBM) reports.

Neuroimaging correlates of persistent fatigue in older adults: A secondary analysis from the Multidomain Alzheimer Preventive Trial (MAPT) trial

OBJECTIVES

Fatigue has been suggested as a marker of biological aging. It seems plausible that this symptom might be associated with changes in brain health. The objective of this study was to examine the associations between persistent fatigue and neuroimaging correlates in a non-disease-specific population of community-dwelling older adults.

METHODS

We performed a cross-sectional analysis using data from The Multidomain Alzheimer Preventive Trial (MAPT). We included 458 subjects. Persistent fatigue was defined as meeting exhaustion criterion of Fried frailty phenotype in two consecutive clinical visits six months apart between study baseline and one year. Brain imaging correlates, assessed by magnetic resonance imaging (MRI), were the outcomes. The associations between persistent fatigue and brain correlates were explored using mixed model linear regressions with random effect at the center level.

RESULTS

The mean age of the participants was 74.8 ± 4 years old, and 63% of the subjects were women. Forty-seven participants (10%) exhibited a persistent fatigue profile. People with persistent fatigue were older compared to subjects without persistent fatigue (76.2 years ± 4.3 vs.74.7 ± 3.9 p = 0.009). Persistent fatigue was associated with higher white matter hyperintensity volume in the fully adjusted analysis. We did not find any cross-sectional association between persistent fatigue and sub-cortical volumes and global and regional cortical thickness.

CONCLUSION

Persistent fatigue was cross-sectionnally associated with higher white matter hyperintensity volume in older adults. Further longitudinal studies, using an assessment tool specifically designed and validated for measuring fatigue, are needed to confirm our findings.

Aberrant functional connectivity between anterior cingulate cortex and left insula in association with therapeutic response to biologics in inflammatory arthritis

BACKGROUND

Brain activity is reported to be associated with individual pain susceptibility and inflammatory status, possibly contributing to disease activity assessment in inflammatory arthritis (IA) including rheumatoid arthritis (RA) and spondyloarthritis (SpA). However, what alteration of brain function associated with disease activity and therapeutic effectiveness in IA remains unclear. We aimed to identify the alterations of brain functional connectivity (FC) shared in both RA and SpA, and evaluate its relationship to anti-rheumatic treatment response using functional magnetic resonance imaging (MRI).

PATIENTS AND METHODS

Structural and resting-state functional MRI data were acquired from patients with IA, patients with osteoarthritis (OA) and heathy controls (HCs). Two datasets were adopted to derive (51 IA, 56 OA, and 17 HCs) and validate (31 IA) the observations. 33 IA patients in the derivation dataset and all the patients in validation dataset required biological treatment and were clinically evaluated before and after therapy. Via whole-brain pair-wise FC analyses, we analyzed IA-specific FC measures relevant to therapeutic response to biologics.

RESULTS

The value of FC between left insular cortex (IC) and anterior cingulate cortex (ACC) was significantly low in IA patients compared with OA patients and HCs. We demonstrated that the FC between left anterior long insular gyrus as a subdivision of IC and ACC was significantly associated with therapeutic response to biologics regarding the improvement of patients' global assessment (PGA) in both derivation and validation datasets.

CONCLUSION

Disease-specific resting-state FC provides a means to assess the therapeutic improvement of PGA and would be a clinical decision-making tool with predictability for treatment response in both RA and SpA.

Different Synaptic Plasticity After Physiological and Psychological Stress in the Anterior Insular Cortex in an Observational Fear Mouse Model

Post-traumatic stress disorder (PTSD) can be triggered not only in people who have personally experienced traumatic events but also in those who witness them. Physiological and psychological stress can have different effects on neural activity, but little is known about the underlying mechanisms. There is ample evidence that the insular cortex, especially the anterior insular cortex (aIC), is critical to both the sensory and emotional experience of pain. It is therefore worthwhile to explore the effects of direct and indirect stress on the synaptic plasticity of the aIC. Here, we used a mouse model of observational fear to mimic direct suffering (Demonstrator, DM) and witnessing (Observer, OB) of traumatic events. After observational fear training, using a 64-channel recording system, we showed that both DM and OB mice exhibited a decreased ratio of paired-pulse with intervals of 50 ms in the superficial layers of the aIC but not in the deep layers. We found that theta-burst stimulation (TBS)–induced long-term potentiation (LTP) in OB mice was significantly higher than in DM mice, and the recruitment of synaptic responses occurred only in OB mice. Compared with naive mice, OB mice showed stronger recruitment and higher amplitude in the superficial layers of the aIC. We also used low-frequency stimulation (LFS) to induce long-term depression (LTD). OB mice showed greater LTD in both the superficial and deep layers of the aIC than naive mice, but no significant difference was found between OB and DM mice. These results provide insights into the changes in synaptic plasticity in the aIC after physiological and psychological stress, and suggest that different types of stress may have different mechanisms. Furthermore, identification of the possible causes of the differences in stress could help treat stress-related disorders.

Multiple-region grey matter atrophy as a predictor for the development of dementia in a community: the Hisayama Study

OBJECTIVE

To assess the association of regional grey matter atrophy with dementia risk in a general older Japanese population.

METHODS

We followed 1158 dementia-free Japanese residents aged ≥65 years for 5.0 years. Regional grey matter volume (GMV) at baseline was estimated by applying voxel-based morphometry methods. The GMV-to-total brain volume ratio (GMV/TBV) was calculated, and its association with dementia risk was estimated using Cox proportional hazard models. We assessed whether the predictive ability of a model based on known dementia risk factors could be improved by adding the total number of regions with grey matter atrophy among dementia-related brain regions, where the cut-off value for grey matter atrophy in each region was determined by receiver operating characteristic curves.

RESULTS

During the follow-up, 113 participants developed all-cause dementia, including 83 with Alzheimer's disease (AD). Lower GMV/TBV of the medial temporal lobe, insula, hippocampus and amygdala were significantly/marginally associated with higher risk of all-cause dementia and AD (all p for trend ≤0.08). The risks of all-cause dementia and AD increased significantly with increasing total number of brain regions exhibiting grey matter atrophy (both p for trend <0.01). Adding the total number of regions with grey matter atrophy into a model consisting of known risk factors significantly improved the predictive ability for AD (Harrell's c-statistics: 0.765-0.802; p=0.02).

CONCLUSIONS

Our findings suggest that the total number of regions with grey matter atrophy among the medial temporal lobe, insula, hippocampus and amygdala is a significant predictor for developing dementia, especially AD, in the general older population.

Neural Correlates of Physical Activity Moderate the Association Between Problematic Mobile Phone Use and Psychological Symptoms

Background

Despite the evidence of an association between problematic mobile phone use (PMPU) and psychological symptoms, a few studies explore whether physical activity (PA) could moderate the effect of PMPU on psychological symptoms and its neural substrates. The aim of this study was to examine the association between PMPU and psychological symptoms in late adolescents, along with the potential moderating effect of PA and neural basis by brain gray matter volume (GMV).

Methods

A total of 251 college students reported on their PMPU, PA, and psychological symptoms and subsequently underwent structural magnetic resonance imaging to explore the neural basis of their PA characteristics. A multiple regression model was performed to detect brain GMV associated with PA by the voxel-based morphometry (VBM) method. Moderating analysis was conducted using PROCESS macro in the SPSS software.

Results

Behavioral results showed that PMPU was correlated to depression, anxiety, and stress, and PA has significantly moderated the association between PMPU with depression, anxiety, and stress. The VBM analysis showed that PA was correlated to GMV of the right fusiform gyrus (FFG), left precuneus (PCUN), left insula (INS), and left triangular part of inferior frontal gyrus (IFGtriang). Moreover, GMV of the left INS moderated the relationship between PMPU and depression.

Conclusion

This study has shed light on the neural perspective of PA that moderates the relationship between PMPU and depressive symptom.

Alice in Wonderland syndrome: a lesion mapping study

BACKGROUND AND PURPOSE

Alice in Wonderland syndrome (AIWS) is a rare neurological disorder, characterized by an erroneous perception of the body schema or surrounding space. It may be caused by a variety of neurological disorders, but to date, there is no agreement on which brain areas are affected. The aim of this study was to identify brain areas involved in AIWS.

METHODS

We conducted a literature search for AIWS cases following brain lesions. Patients were classified according to their symptoms as type A (somesthetic), type B (visual), or type C (somesthetic and visual). Using a lesion mapping approach, lesions were mapped onto a standard brain template and sites of overlap were identified.

RESULTS

Of 30 lesions, maximum spatial overlap was present in six cases. Local maxima were identified in the right occipital lobe, specifically in the extrastriate visual cortices and white matter tracts, including the ventral occipital fasciculus, optic tract, and inferior fronto-occipital fasciculus. Overlap was primarily due to type B patients (the most prevalent type, n = 22), who shared an occipital site of brain damage. Type A (n = 5) and C patients (n = 3) were rarer, with lesions disparately located in the right hemisphere (thalamus, insula, frontal lobe, hippocampal/parahippocampal cortex).

CONCLUSIONS

Lesion-associated AIWS in type B patients could be related to brain damage in visual pathways located preferentially, but not exclusively, in the right hemisphere. Conversely, the lesion location disparity in cases with somesthetic symptoms suggests underlying structural/functional disconnections requiring further evaluation.

Delineating neural responses and functional connectivity changes during vestibular and nociceptive stimulation reveal the uniqueness of cortical vestibular processing

Vestibular information is ubiquitous and often processed jointly with visual, somatosensory and proprioceptive information. Among the cortical brain regions associated with human vestibular processing, area OP2 in the parietal operculum has been proposed as vestibular core region. However, delineating responses uniquely to vestibular stimulation in this region using neuroimaging is challenging for several reasons: First, the parietal operculum is a cytoarchitectonically heterogeneous region responding to multisensory stimulation. Second, artificial vestibular stimulation evokes confounding somatosensory and nociceptive responses blurring responses contributing to vestibular perception. Furthermore, immediate effects of vestibular stimulation on the organization of functional networks have not been investigated in detail yet. Using high resolution neuroimaging in a task-based and functional connectivity approach, we compared two equally salient stimuli—unilateral galvanic vestibular (GVS) and galvanic nociceptive stimulation (GNS)—to disentangle the processing of both modalities in the parietal operculum and characterize their effects on functional network architecture. GNS and GVS gave joint responses in area OP1, 3, 4, and the anterior and middle insula, but not in area OP2. GVS gave stronger responses in the parietal operculum just adjacent to OP3 and OP4, whereas GNS evoked stronger responses in area OP1, 3 and 4. Our results underline the importance of considering this common pathway when interpreting vestibular neuroimaging experiments and underpin the role of area OP2 in central vestibular processing. Global network changes were found during GNS, but not during GVS. This lack of network reconfiguration despite the saliency of GVS may reflect the continuous processing of vestibular information in the awake human.

Clinical considerations on a right operculo-insular cavernous angioma: an illustrative case

The insular cortex is considered one of the most complex regions of the brain, defined as the "hub" of somatosensory areas. Here, we examine the case of a surgically treated haemorrhagic cavernoma involving the middle and posterior insular cortex, presenting both sensory, gustative and speech symptoms. By reviewing the recent findings in humans' and primates' basic research, we illustrated clinical and radiological correlations of the reported case, confirming insular role in sensitive and gustatory functions.

Cannabidiol effectively reverses mechanical and thermal allodynia, hyperalgesia, and anxious behaviors in a neuropathic pain model: Possible role of CB1 and TRPV1 receptors

The incidence of chronic pain is high in the general population and it is closely related to anxiety disorders, which promote negative effects on the quality of life. The cannabinoid system has essential participation in the pain sensitivity circuit. In this perspective, cannabidiol (CBD) is considered a promising strategy for treating neuropathic pain. Our study aimed to evaluate the effects of sub-chronic systemic treatment with CBD (0.3, 3, 10, or 30 mg/kg, i.p.) in male in rats submitted to chronic constriction injury of the sciatic nerve (CCI) or not (SHAM) and assessed in nociceptive tests (von Frey, acetone, and hot plate, three days CBD's treatment) and in the open field test (OFT, two days CBD's treatment). We performed a screening immunoreactivity of CB1 and TRPV1 receptors in cortical and limbic regions tissues, which were collected after 1.5 h of behavioral tests on the 24th experimental day. This study presents a dose-response curve to understand better the effects of low doses (3 mg/kg) on CBD's antiallodynic and anxiolytic effects. Also, low doses of CBD were able to (1) reverse mechanical and thermal allodynia (cold) and hyperalgesia, (2) reverse anxious behaviors (reduction of the % of grooming and freezing time, and increase of the % of center time in the OFT) induced by chronic pain. The peripheral neuropathy promoted the increase in the expression of CB1 and TRPV1 receptors in the anterior cingulate cortex (ACC), anterior insular cortex (AIC), basolateral amygdala (BLA), dorsal hippocampus (DH), and ventral hippocampus (VH). CBD potentiated this effect in the ACC, AIC, BLA, DH, and VH regions. These results provide substantial evidence of the role of the ACC-AIC-BLA corticolimbic circuit, and BLA-VH for pain regulation. These results can be clinically relevant since they contribute to the evidence of CBD's beneficial effects on treating chronic pain and associated comorbidities such as anxiety.

The role of lateralisation and sex on insular cortex: 3D volumetric analysis

Background/aim

The insula has attracted the attention of many neuroimaging studies because of its key role between brain structures. However, the number of studies investigating the effect of sex and laterality on insular volume is insufficient. The aim of this study was to investigate the differences in insular volume between sexes and hemispheres.

Materials and methods

A total of 47 healthy participants [24 males (20.08 ± 1.44 years) and 23 females (19.57 ± 0.90 years)] underwent magnetic resonance imaging (MRI). Imaging was performed using the 3T MRI scanner. The insular volume was measured using the Individual Brain Atlases using Statistical Parametric Mapping (IBASPM); total intracranial, cerebral, grey and white matter volumes were measured using volBrain.

Results

The right insular volume was significantly higher than the left insular volume in the participants, and the left cerebral volume was significantly higher than the right cerebral volume (p < 0.05). The total brain, total cerebral, left and right insular, and cerebral volumes were significantly larger in males than in females (p < 0.001). Also, the ratios of the insular volume to total brain and cerebral volume were significantly higher in males than in females (p < 0.05).

Conclusion

This study shows that insular volume differs with laterality and sex. This outcome may be explained by the anatomical relationship between the insula and behavioural functions and emotional reactions and the fact that the right side of the brain is best at expressive and creative tasks.

Altered Functional Connectivity Within and Between Salience and Sensorimotor Networks in Patients With Functional Constipation

Functional constipation (FCon) is a common functional gastrointestinal disorder. A considerable portion of patients with FCon is associated with anxiety/depressive status (FCAD). Previous neuroimaging studies mainly focused on patients with FCon without distinguishing FCAD from FCon patients without anxiety/depressive status (FCNAD). Differences in brain functions between these two subtypes remain unclear. Thus, we employed resting-state functional magnetic resonance imaging (RS-fMRI) and graph theory method to investigate differences in brain network connectivity and topology in 41 FCAD, 42 FCNAD, and 43 age- and gender-matched healthy controls (HCs). FCAD/FCNAD showed significantly lower normalized clustering coefficient and small-world-ness. Both groups showed altered nodal degree/efficiency mainly in the rostral anterior cingulate cortex (rACC), precentral gyrus (PreCen), supplementary motor area (SMA), and thalamus. In the FCAD group, nodal degree in the SMA was negatively correlated with difficulty of defecation, and abdominal pain was positively correlated with nodal degree/efficiency in the rACC, which had a lower within-module nodal degree. The salience network (SN) exhibited higher functional connectivity (FC) with the sensorimotor network (SMN) in FCAD/FCNAD, and FC between these two networks was negatively correlated with anxiety ratings in FCAD group. Additionally, FC of anterior insula (aINS)-rACC was only correlated with constipation symptom (i.e., abdominal pain) in the FCNAD group. In the FCAD group, FCs of dorsomedial prefrontal cortex-rACC, PreCen-aINS showed correlations with both constipation symptom (i.e., difficulty of defecation) and depressive status. These findings indicate the differences in FC of the SN-SMN between FCAD and FCNAD and provide neuroimaging evidence based on brain function, which portrays important clues for improving new treatment strategies.

Targeting the Autonomic Nervous System for Risk Stratification, Outcome Prediction and Neuromodulation in Ischemic Stroke

Ischemic stroke is a worldwide major cause of mortality and disability and has high costs in terms of health-related quality of life and expectancy as well as of social healthcare resources. In recent years, starting from the bidirectional relationship between autonomic nervous system (ANS) dysfunction and acute ischemic stroke (AIS), researchers have identified prognostic factors for risk stratification, prognosis of mid-term outcomes and response to recanalization therapy. In particular, the evaluation of the ANS function through the analysis of heart rate variability (HRV) appears to be a promising non-invasive and reliable tool for the management of patients with AIS. Furthermore, preclinical molecular studies on the pathophysiological mechanisms underlying the onset and progression of stroke damage have shown an extensive overlap with the activity of the vagus nerve. Evidence from the application of vagus nerve stimulation (VNS) on animal models of AIS and on patients with chronic ischemic stroke has highlighted the surprising therapeutic possibilities of neuromodulation. Preclinical molecular studies highlighted that the neuroprotective action of VNS results from anti-inflammatory, antioxidant and antiapoptotic mechanisms mediated by α7 nicotinic acetylcholine receptor. Given the proven safety of non-invasive VNS in the subacute phase, the ease of its use and its possible beneficial effect in hemorrhagic stroke as well, human studies with transcutaneous VNS should be less challenging than protocols that involve invasive VNS and could be the proof of concept that neuromodulation represents the very first therapeutic approach in the ultra-early management of stroke.

Displaying the autonomic processing network in humans - a global tractography approach

Regulation of the internal homeostasis is modulated by the central autonomic system. So far, the view of this system is determined by animal and human research focusing on cortical and subcortical grey substance regions. To provide an overview based on white matter architecture, we used a global tractography approach to reconstruct a network of tracts interconnecting brain regions that are known to be involved in autonomic processing. Diffusion weighted imaging data were obtained from subjects of the human connectome project (HCP) database. Resulting tracts are in good agreement with previous studies assuming a division of the central autonomic system into a cortical (CAN) and a subcortical network (SAN): the CAN consist of three subsystems that encompass all cerebral lobes and overlap within the insular cortex: a parieto-anterior-temporal pathway (PATP), an occipito-posterior-temporo-frontal pathway (OPTFP) and a limbic pathway. The SAN on the other hand connects the hypothalamus to the periaqueductal grey and locus coeruleus, before it branches into a dorsal and a lateral part that target autonomic nuclei in the rostral medulla oblongata. Our approach furthermore reveals how the CAN and SAN are interconnected: the hypothalamus can be considered as the interface-structure of the SAN, whereas the insula is the central hub of the CAN. The hypothalamus receives input from prefrontal cortical fields but is also connected to the ventral apex of the insular cortex. Thus, a holistic view of the central autonomic system could be created that may promote the understanding of autonomic signaling under physiological and pathophysiological conditions.

The posterior insular cortex is necessary for the consolidation of tone fear conditioning

The insular cortex (IC) is notably implicated in emotional and cognitive processing; however, little is known regarding to what extent its two main subregions play functionally distinct roles on memory consolidation of conditioned fear tasks. Here we verified the effects of temporary functional inactivation of the anterior (aIC) and posterior IC (pIC) on contextual and tone fear memory. Rats received post-training bilateral infusions of the GABA_A receptor agonist muscimol into either the aIC or pIC and were tested 48 and 72 h after the delay tone fear conditioning session to assess the background contextual (CFC) and tone (TFC) fear conditioning, respectively. Inactivation of the aIC during memory consolidation did not affect fear memory for CFC or TFC. On the other hand, post-training inactivation of the pIC impaired TFC but not CFC. Our findings indicate that the pIC is a necessary part of the neural circuitry related to the consolidation of cued-fear memories.

Common and distinct neural correlates of music and food-induced pleasure: A coordinate-based meta-analysis of neuroimaging studies

Neuroimaging studies have shown that, despite the abstractness of music, it may mimic biologically rewarding stimuli (e.g., food) in its ability to engage the brain's reward circuitry. However, due to the lack of research comparing music and other types of reward, it is unclear to what extent the recruitment of reward-related structures overlaps among domains. To achieve this goal, we performed a coordinate-based meta-analysis of 38 neuroimaging studies (703 subjects) comparing the brain responses specifically to music and food-induced pleasure. Both engaged a common set of brain regions, including the ventromedial prefrontal cortex, ventral striatum, and insula. Yet, comparative analyses indicated a partial dissociation in the engagement of the reward circuitry as a function of the type of reward, as well as additional reward type-specific activations in brain regions related to perception, sensory processing, and learning. These results support the idea that hedonic reactions rely on the engagement of a common reward network, yet through specific routes of access depending on the modality and nature of the reward.

Neural mechanisms of emotions, alexithymia, and depression

This chapter brings the powerful conceptual tools of the science of parallel distributed processing (PDP) to bear on the cognitive neuroscience of emotions discussed in this book. Cerebral representations are encoded as patterns of activity involving billions of neurons. PDP across these neuronal populations provides the basis for a number of emergent properties: (1) processing occurs and knowledge (long term memories) is stored (as synaptic connection strengths) in exactly the same networks; (2) networks have the capacity for setting into stable attractor states corresponding to concepts, symbols, implicit rules, or data transformations; (3) networks provide the scaffold for the acquisition of knowledge, but knowledge is acquired through experience; (4) PDP networks are adept at incorporating the statistical regularities of experience as well as frequency and age of acquisition effects; (5) networks enable content-addressable memory; (6) because knowledge is distributed throughout networks, they exhibit the property of graceful degradation; (7) networks intrinsically provide the capacity for inference. With this perspective, I propose a new model of emotional function that reasonably accounts for the effects of focal lesions at various points (insula, orbitofrontal cortex, convexity cortex, and intervening white matter) due to stroke, trauma, surgery, and degenerative disease, as reflected in disorders of affective prosody, facial emotional comprehension and expression, emotional behavior, and personality. I consider a modification of the James Lange theory that takes into account the role of a lifetime of subjective knowledge acquisition by the orbitofrontal cortex. Alexithymia is conceptualized as a disorder of the insula/orbitofrontal cortex/dorsolateral prefrontal cortex (DL-PFC) system, the function of which can be disrupted by degradation of knowledge at a number of different locations. Finally, I consider the possibility that depression reflects pathological learning involving the medial and lateral orbitofrontal cortices such that there is a pathologic engagement of the two regions, as suggested by Rolls. I conclude with a consideration of the peculiar responsivity of depression to serotonergic and noradrenergic agents, as well as to surgical orbitofrontal undercutting, and what that might be telling us about the mechanisms of depression and its treatment.

Alexithymia

Humans are highly adept at differentiating, regulating, and responding to their emotions. At the core of all these functions is emotional awareness: the conscious feeling states that are central to human mental life. Disrupted emotional awareness-a subclinical construct commonly referred to as alexithymia-is present in a range of psychiatric and neurological disorders and can have a deleterious impact on functional outcomes and treatment response. This chapter is a selective review of the current state of the science on alexithymia. We focus on two separate but related issues: (i) the functional deficits associated with alexithymia and what they reveal about the importance of emotional awareness for shaping normative human functioning, and (ii) the neural correlates of alexithymia and what they can inform us about the biological bases of emotional awareness. Lastly, we outline challenges and opportunities for alexithymia research, focusing on measurement issues and the potential utility of formal computational models of emotional awareness for advancing the fields of clinical and affective science.

The insular cortex as a vestibular area in relation to autonomic function

The forebrain cerebral network including the insular cortex plays a crucial role in the regulation of the central autonomic nervous system in relation to emotional stress. Numerous studies have recently shown that the insular cortex also has roles as a vestibular area in addition to auditory function. In this review, we summarize the recent literature regarding the relationship between the insular cortex and vestibular function, and we describe our hypothesis that the insular cortex has a pivotal role in vestibular-cardiovascular integration.

Bilateral asymmetric tonic seizure in insulo-opercular epilepsy: an anatomo-electro-clinical study

Background

Insulo-opercular seizures are highly heterogeneous in seizure semiology and electrical features. Bilateral asymmetric limb posturing, as a classical pattern of supplementary sensorimotor area (SMA) seizure, also occurs in insulo-opercular epilepsy. This study was aimed to study the anatomo-electro-clinical correlations in bilateral asymmetric tonic seizures (BATS), in order to advance the understanding of insulo-opercular epilepsy.

Methods

Eight patients with insulo-opercular epilepsy as confirmed by stereoelectroencephalography (SEEG) and manifesting BATS as the major ictal motor sign, in Guangdong Sanjiu Brain Hospital Epilepsy Center from 2014 to 2018, were employed in this study. The BATS of the patients were evaluated, and the semiologic features and concomitant intracerebral EEG changes were quantified. Then the variables were examined with Cluster Analysis, and the semiologic features were correlated with anatomic localization using the Kendall correlation test.

Results

Of the 8 patients, the most frequent initial motor sign was bilateral asymmetric tonic posturing (62.5%). Facial tonic-clonic sign also had a high prevalence in the evolution of seizures (87.5%). The results of Cluster Analysis showed that the semiologic features were subdivided into two main groups, one group comprising exclusively BATS and the other including signs of focal tonic seizure, aura, focal limb tonic-clonic seizure (TCS), facial TCS, hypermotor behavior, eye movement, autonomic changes and generalized TCS. The BATS was strongly associated with the posterior long gyrus (PLG) of insula (t = 0.732) and parietal operculum (t = 1.000); the hypermotor behaviors were associated with the anterior long gyrus (ALG) (t = 0.770); and the autonomic changes were associated with the anterior limiting sulcus (ALS) (t = 0.734) and middle short gyrus (MSG) (t = 0.700).

Conclusions

The seizure semiology of insulo-opercular epilepsy is characterized, in temporal order, by BATS, with or without simultaneous hypermotor behaviors, and frequently ends up with facial tonic-clonic signs, which is different from that of the SMA seizure. The early spread network involving the posterior insular lobe and parietal operculum may contribute to this pattern of manifestation.

Endogenous opioid and cannabinoid systems contribute to antinociception produced by administration of NSAIDs into the insular cortex of rats

Pain sensation is characterized as a complex experience, dependent on sensory processes as well as the activation of limbic brain areas involved in emotion, among them anterior insula. This cortical area is involved in the perception and response to painful stimuli. We investigated if this area contributes to antinociception produced by NSAIDs, and underlying mechanisms. We found that administration of NSAIDs into the anterior insular cortex in rats reduced mechanical and heat hyperalgesia produced by intraplantar injection of formalin, and this was attenuated by pre- or post-treatment with the opioid receptor antagonists, naloxone and CTOP, and the cannabinoid receptor (CB1) antagonist AM-251. These data support the concept that NSAID-evoked antinociception is mediated via descending endogenous opioid and cannabinoid systems inhibiting spinal paw withdrawal reflexes in rodents.