The Anterior Insula and its Projection to the Prelimbic Cortex are Involved in the Regulation of 5-HT-Induced Itch / 神经科学通报·英文版

Itch is an unpleasant sensation that urges people and animals to scratch. Neuroimaging studies on itch have yielded extensive correlations with diverse cortical and subcortical regions, including the insular lobe. However, the role and functional specificity of the insular cortex (IC) and its subdivisions in itch mediation remains unclear. Here, we demonstrated by immunohistochemistry and fiber photometry tests, that neurons in both the anterior insular cortex (AIC) and the posterior insular cortex (PIC) are activated during acute itch processes. Pharmacogenetic experiments revealed that nonselective inhibition of global AIC neurons, or selective inhibition of the activity of glutaminergic neurons in the AIC, reduced the scratching behaviors induced by intradermal injection of 5-hydroxytryptamine (5-HT), but not those induced by compound 48/80. However, both nonselective inhibition of global PIC neurons and selective inhibition of glutaminergic neurons in the PIC failed to affect the itching-scratching behaviors induced by either 5-HT or compound 48/80. In addition, pharmacogenetic inhibition of AIC glutaminergic neurons effectively blocked itch-associated conditioned place aversion behavior, and inhibition of AIC glutaminergic neurons projecting to the prelimbic cortex significantly suppressed 5-HT-evoked scratching. These findings provide preliminary evidence that the AIC is involved, at least partially via aversive emotion mediation, in the regulation of 5-HT-, but not compound 48/80-induced itch.

Activation of Cannabinoid Receptor 1 in GABAergic Neurons in the Rostral Anterior Insular Cortex Contributes to the Analgesia Following Common Peroneal Nerve Ligation / 神经科学通报·英文版

The rostral agranular insular cortex (RAIC) has been associated with pain modulation. Although the endogenous cannabinoid system (eCB) has been shown to regulate chronic pain, the roles of eCBs in the RAIC remain elusive under the neuropathic pain state. Neuropathic pain was induced in C57BL/6 mice by common peroneal nerve (CPN) ligation. The roles of the eCB were tested in the RAIC of ligated CPN C57BL/6J mice, glutamatergic, or GABAergic neuron cannabinoid receptor 1 (CB1R) knockdown mice with the whole-cell patch-clamp and pain behavioral methods. The E/I ratio (amplitude ratio between mEPSCs and mIPSCs) was significantly increased in layer V pyramidal neurons of the RAIC in CPN-ligated mice. Depolarization-induced suppression of inhibition but not depolarization-induced suppression of excitation in RAIC layer V pyramidal neurons were significantly increased in CPN-ligated mice. The analgesic effect of ACEA (a CB1R agonist) was alleviated along with bilateral dorsolateral funiculus lesions, with the administration of AM251 (a CB1R antagonist), and in CB1R knockdown mice in GABAergic neurons, but not glutamatergic neurons of the RAIC. Our results suggest that CB1R activation reinforces the function of the descending pain inhibitory pathway via reducing the inhibition of glutamatergic layer V neurons by GABAergic neurons in the RAIC to induce an analgesic effect in neuropathic pain.

As artérias lenticuloestriadas podem interferir na extensão da ressecção tumoral e sobrevida nos gliomas da ínsula? / Can lenticulostriated arteries interfere with the extent of tumor resection and survival in insula gliomas?

Introdução: Os gliomas são tumores encefálicos e da medula espinhal que se originam nas células gliais e cuja progressão invade o tecido cerebral adjacentee e dentre eles um dos mais desafiadores são localizados no lobo cerebral da ínsula. Estas artérias irrigam estruturas nobres e sua lesão pode produzir danos sensitivos, motores e de linguagem. Objetivo: Descrever o impacto da extensão da ressecção, sobrevida global e dos resultados funcionais após a cirurgia dos gliomas insulares, quando estes tumores estejam ou não envolvidos pelas artérias lenticuloestriadas. Métodos: Revisão integrativa nas plataformas virtuais em português e inglês, buscando AND ou OR dados através dos seguintes descritores "Gliomas da ínsula, Mapeamento cerebral, Artérias lenticuloestriadas". A busca inicial foi baseada no título e/ou resumo. Decididos os trabalhos incluíveis foi realizada a leitura na íntegra dos textos. Ao total foram estudados 55 artigos. Resultados: O lobo da ínsula fica "escondido" pela sobreposição dos lobos frontal, parietal e temporal. Para alcançá-lo pode-se realizar as abordagens transsilviana ou transcortical. Ocorre que ao chegar na ínsula visualiza-se significativa ramificação constituída pelas artérias lenticuloestriadas, cuja manipulação pode determinar déficit neurológico e, ao se aprofundar no córtex insular, depara-se com outras estruturas tão importantes quanto a própria ínsula. O conhecimento anatômico das artérias lenticuloestriadas e suas relações é de fundamental importância para a ressecção de glioma insular, pois o comprometimento delas e da artéria cerebral média podem determinar a isquemia dos núcleos da base e da cápsula interna. Conclusão: O tratamento dos gliomas insulares permanece como grande desafio. Devido à sua localização e possibilidade de desenvolvimento de déficits neurológicos na manipulação cirúrgica é necessário não somente conhecer sua localização topográfica, mas também a íntima relação vascular com as artérias lenticuloestriadas. O envolvimento delas pelo tumor possui implicações na sobrevida e na preservação da função neurológica. O conhecimento detalhado da anatomia da região é fundamental para diminuir complicações que afetem grandemente a qualidade de vida dos pacientes.

Introduction: Gliomas are brain and spinal cord tumors that originate in glial cells and whose progression invades the adjacent brain tissue and among them one of the most challenging are located in the cerebral lobe of the insula. These arteries supply noble structures and their damage can cause sensory, motor and language damage. Objective: To describe the impact of the extent of resection, overall survival and functional results after surgery for insular gliomas, when these tumors are or are not involved by lenticulostriate arteries. Methods: Integrative review on virtual platforms in Portuguese and English, searching for AND or OR data using the following descriptors "Insula gliomas, Brain mapping, Lenticulostriate arteries". The initial search was based on the title and/or abstract. Once the included works were decided, the texts were read in full. In total, 55 articles were studied. Results: The insula lobe is "hidden" by the overlap of the frontal, parietal and temporal lobes. To achieve this, transsylvian or transcortical approaches can be performed. It turns out that when arriving at the insula, a significant branch made up of lenticulostriate arteries is seen, the manipulation of which can cause neurological deficits and, when going deeper into the insular cortex, one comes across other structures as important as the insula itself. Anatomical knowledge of the lenticulostriate arteries and their relationships is of fundamental importance for the resection of insular glioma, as their involvement and that of the middle cerebral artery can determine ischemia of the basal ganglia and internal capsule. Conclusion: The treatment of insular gliomas remains a major challenge. Due to its location and the possibility of developing neurological deficits during surgical manipulation, it is necessary not only to know its topographic location, but also the intimate vascular relationship with the lenticulostriate arteries. Their involvement by the tumor has implications for survival and preservation of neurological function. Detailed knowledge of the region's anatomy is essential to reduce complications that greatly affect patients' quality of life.

Unveiling the Insular Lobe of Reil: Neurophysiological and Anatomical Features

The insular lobe has long been investigated, from its anatomical descriptions to its neurophysiological activity. Located in a central location, the insular lobe participates in several afferent and efferent pathways, forming part of the eloquent and fundamental structures that make up the central core of the brain. The lobe of the insula has participation in language function, such as speech, sensory (e.g., taste), limbic, autonomic (visceral), also forming part of complex associative circuits, including part of the circuits of mirror neurons. Several functional descriptions attributed to the insular lobe have beenmade in patients suffering fromcerebrovascular diseases, as well as in those with epilepsy. Much progress and many descriptions have also been made in patients with tumors. Despite much information already available about the insular lobe, it is likely that much will be discovered in the coming years.

The Role of the IntraoperativeAuxiliaryMethods in the Resection of Motor Area Lesions / O papel dos métodos auxiliares intraoperatórios na ressecção de lesões em área motora

Objective In recent years, technologies have advanced considerably in improving surgical outcome following treatment of lesions in eloquent brain areas. The aimof this study is to explore which method is best in the resection of motor area lesions. Methods Prospective, non-randomized study Evaluate on 74 patients who underwent surgery to remove lesions around the motor area. Results Total lesion removal was achieved in 68 patients (93.1%). Fifty-four patients (73.9%) presented normal motor function in the preoperative period; of these, 20 (37.3%) developed transitory deficits. Nevertheless, 85% of these patients later experienced a complete recovery. Nineteen patients presented with motor deficits preoperatively; of these, five presented deteriorating motor abilities. Intraoperative stimulation methods were used in 65% of the patients, primarily in cases of glioma. Conclusions The morbidity in patients submitted to resections of motor area lesions is acceptable and justify the surgical indication with the purpose of maximal resection. Intraoperative stimulation is an important tool that guides glioma resection in many cases.

Objetivo Nos últimos anos, consideráveis avanços tecnológicos têm surgido no sentido de melhorar os resultados cirúrgicos no tratamento de lesões em áreas eloquentes do cérebro. O objetivo deste estudo é investigar qual o melhor método para ressecção de lesões em área motora. Método Estudo prospectivo não aleatório que avaliou os resultados pós-operatórios em 74 pacientes submetidos à ressecção de lesões em área motora ou adjacente. Resultados A ressecção cirúrgica foi considerada total em 68 (93,1%) pacientes. 54 pacientes (73,9%) apresentavam força muscular normal no pré-operatório. Destes, 20 (37,3%) apresentaram déficit no pós-operatório imediato, sendo que 17 (85%) recuperaram completamente o déficit. 19 pacientes apresentavam déficit no préoperatório, sendo que 05 apresentaram piora do déficit no pós-operatório imediato. A estimulação intraoperatória foi utilizada em 65% dos casos, principalmente nos gliomas. Conclusão Amorbidade empacientes operados de lesões emáreamotora é bastante aceitável e justifica a indicação cirúrgica com objetivo de ressecção máxima. A estimulação intraoperatória é uma ferramenta importante para guiar a resseção dos gliomas em muitos casos.