Practical aspects of functional mri in clinical examinations / Aspectos práticos de rm funcional em exames clínicos / Aspectos prácticos de la rm funcional en los exámenes clínicos

The eloquent cerebral cortices are involved in movement, sensation, speech, vision, and higher cortical functions. Functional magnetic resonance imaging (fMRI) allows the evaluation of brain function, aiding in neurosurgical planning by mapping eloquent cortical areas. Considering the high cost of the hardware involved, the purpose of this work is to present a more affordable, in-house alternative for these studies that can provide adequate results in a clinical setting. We also present some practical information on how to perform these exams. We describe an affordable in-house hardware solution used by an imaging center, and examples of fMRI paradigms used to evaluate motor and language tasks. The fMRI studies show robust activations in eloquent areas consistent with the tasks performed on the exam. Images of post-processed studies illustrate clinical cases. The fMRI have well-established applications, mapping eloquent cortical areas in patients with brain lesions. In the case of surgical planning, it allows the surgeon to maximize the resection area while minimizing sequelae. More affordable hardware can reduce the cost of these exams, making them more accessible to the general public.

O córtex cerebral eloquente está envolvido nas atividades motora, sensação, fala, visão e funções corticais superiores. A ressonância magnética funcional (RMf) permite a avaliação da função cerebral, ajudando no planejamento neurocirúrgico através do mapeamento de áreas corticais eloquentes. Considerando o elevado custo do hardware envolvido, o objetivo deste trabalho é apresentar uma alternativa mais acessível para estes estudos, que possa fornecer resultados adequados em um ambiente clínico. Também apresentamos algumas informações práticas sobre a realização destes exames. Descrevemos uma solução de hardware acessível utilizada por um centro de imagens, e exemplos de paradigmas de RMf usados para avaliar tarefas motoras e relacionadas à fala. Os estudos de RMf mostram ativações em áreas eloquentes, consistentes com as tarefas realizadas no exame com imagens de estudos pós-processados ilustrando casos clínicos. A RMf tem aplicações bem estabelecidas, mapeando áreas corticais eloquentes em pacientes com lesões cerebrais. No caso do planejamento cirúrgico, permite que o cirurgião maximize a área de ressecção enquanto minimiza potenciais sequelas. Equipamentos mais acessíveis podem reduzir o custo destes exames, podendo aumentar a disponibilização ao público em geral.

La corteza cerebral elocuente está implicada en las actividades motoras, la sensibilidad, el habla, la visión y las funciones corticales superiores. La resonancia magnética funcional (RMf) permite la evaluación de la función cerebral, ayudando en la planificación neuroquirúrgica mediante el mapeo de las áreas corticales elocuentes. Teniendo en cuenta el elevado coste del hardware implicado, el objetivo de este artículo es presentar una alternativa más asequible para estos estudios que pueda proporcionar resultados adecuados en un entorno clínico. También presentamos información práctica sobre cómo realizar estos exámenes. Describimos una solución de hardware asequible utilizada por un centro de diagnóstico por imagen, y ejemplos de paradigmas de RMf utilizados para evaluar tareas motoras y relacionadas con el habla. Los estudios de RMf muestran activaciones en áreas elocuentes, coherentes con las tareas realizadas en el examen, con imágenes de estudios postprocesados que ilustran casos clínicos. La RMf tiene aplicaciones bien establecidas en el mapeo de áreas corticales elocuentes en pacientes con lesiones cerebrales. En el caso de la planificación quirúrgica, permite al cirujano maximizar el área de resección minimizando las posibles secuelas. Un equipo más asequible puede reducir el coste de estas exploraciones, aumentando potencialmente su disponibilidad para el público en general.

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.

Magnetoencephalography in clinical practice / Magnetoencefalografia na prática clínica

ABSTRACT Magnetoencephalography (MEG) is a neurophysiological technique that measures the magnetic fields associated with neuronal activity in the brain. It is closely related but distinct from its counterpart electroencephalography (EEG). The first MEG was recorded more than 50 years ago and has technologically evolved over this time. It is now well established in clinical practice particularly in the field of epilepsy surgery and functional brain mapping. However, underutilization and misunderstanding of the clinical applications of MEG is a challenge to more widespread use of this technology. A fundamental understanding of the neurophysiology and physics of MEG is discussed in this article as well as practical issues related to implementation, analysis, and clinical applications. The future of MEG and some potential clinical applications are briefly reviewed.

RESUMO A magnetoencefalografia (MEG) é uma técnica neurofisiológica que mede os campos magnéticos associados à atividade neuronal no cérebro. A técnica é distinta da eletroencefalografia (EEG), porém está intimamente relacionada a ela. A primeira foi registrada há mais de 50 anos e evoluiu tecnologicamente ao longo do tempo. Está agora bem estabelecida na prática clínica, particularmente nos campos da cirurgia de epilepsia e mapeamento cerebral funcional. No entanto, a subutilização e a incompreensão das aplicações clínicas da MEG são um desafio para o uso mais amplo dessa tecnologia. Suas bases neurofisiológica e física são discutidas neste artigo, bem como questões práticas relacionadas à sua implementação, análise e aplicações clínicas. O futuro da MEG e algumas aplicações clínicas potenciais são brevemente revistos.

Surgical treatment of drug-resistant epilepsy caused by gliomas in eloquent areas: experience report / Tratamento cirúrgico de epilepsias refratárias causadas por gliomas localizados em áreas eloquentes: uma série de casos brasileiros

ABSTRACT Drug-resistant epilepsy associated with central nervous system tumors is generally caused by low grade gliomas. This group of tumors is usually found in brain eloquent areas, such as the insular lobe, rolandic cortex and supplementary motor area and, historically, possess a greater risk of postoperative deficits. Objective: The aim of this investigation was to present our surgical experience on patients with drug-resistant epilepsy caused by gliomas in eloquent areas. We retrospectively investigated variables that impact seizure control, such as tumor location, extent of resection, invasion into the lenticulostriate arteries in the patient, especially those with insular gliomas. Methods: Out of 67 patients with eloquent area brain tumors operated on in our service between 2007 and 2016, 14 patients had symptoms of drug-resistant epilepsy. Volumetric analysis, extent of resection (EOR), type of approach and mapping, among other factors were correlated with the 12-month postoperative seizure outcome. Results: Univariate analysis showed that the factors showing statistical relevance with seizure control were preoperative volume (p = 0.005), EOR (p = 0.028) and postoperative volume (p = 0.030). Conclusion: There was a statistically significant association between the EOR and the Engel score for epilepsy control: an EOR < 70 was associated with Engel II, III, IV and an EOR > 90 was associated with Engel I. Eloquent area gliomas can safely be resected when surgeons use not only microsurgical anatomy concepts but also brain mapping.

RESUMO Epilepsia refratária secundária a tumores cerebrais são geralmente causadas por gliomas de baixo grau. Esse grupo de tumor é frequentemente localizado em áreas eloquentes do cérebro como na insula, córtex rolândico e área motora suplementar; e sua ressecção apresenta alto risco de déficits neurológicos no pós operatório. Objetivo: O objetivo do estudo consiste em apresentar nossa experiência no tratamento cirúrgico de pacientes com epilepsia refratária secundário a gliomas em áreas eloquentes. Métodos: O estudo consiste em investigação retrospectiva de variáveis que interferem no controle de crises, tais como localização do tumor, grau de ressecção, invasão tumoral de artérias lenticulo estriadas, principalmente em gliomas insulares. Dentre 67 pacientes portadores de gliomas em área eloquente operados no período de 2007 a 2016, 14 doentes apresentavam epilepsia refrataria associada. Análise volumétrica do tumor, grau de ressecção, acesso cirúrgico, bem como o uso de mapeamento cortical intraoperatório foram correlacionados com desfecho de controle de crises epilepticas em 12 meses. Resultados: Em análise univariada os fatores relacionados com controle de crises em 12 meses foram volume tumoral pré operatório (p = 0,005), grau de ressecção (p = 0,028) e volume tumoral pós operatório. Conclusão: O grau de ressecção apresentou significância estatística em relação ao controle de crises conforme escala de Engel. Ressecções menores que 70% apresentaram correlação com Engel II, III e IV; enquanto ressecções maiores que 90% apresentaram correção positiva com Engel I. Gliomas em áreas eloquentes podem ser ressecados de forma segura desde que seja realizada por equipe experiente com conhecimento acurado da anatomia microcirúrgica e emprego de mapeamento cortical intraoperatório.

Seed-Based Resting-State Functional MRI for Presurgical Localization of the Motor Cortex: A Task-Based Functional MRI-Determined Seed Versus an Anatomy-Determined Seed

OBJECTIVE: For localization of the motor cortex, seed-based resting-state functional MRI (rsfMRI) uses the contralateral motor cortex as a seed. However, research has shown that the location of the motor cortex could differ according to anatomical variations. The purpose of this study was to compare the results of rsfMRI using two seeds: a template seed (the anatomically expected location of the contralateral motor cortex) and a functional seed (the actual location of the contralateral motor cortex determined by task-based functional MRI [tbfMRI]). MATERIALS AND METHODS: Eight patients (4 with glioma, 3 with meningioma, and 1 with arteriovenous malformation) and 9 healthy volunteers participated. For the patients, tbfMRI was performed unilaterally to activate the healthy contralateral motor cortex. The affected ipsilateral motor cortices were mapped with rsfMRI using seed-based and independent component analysis (ICA). In the healthy volunteer group, both motor cortices were mapped with both-hands tbfMRI and rsfMRI. We compared the results between template and functional seeds, and between the seed-based analysis and ICA with visual and quantitative analysis. RESULTS: For the visual analysis, the functional seed showed significantly higher scores compared to the template seed in both the patients (p = 0.002) and healthy volunteers (p < 0.001). Although no significant difference was observed between the functional seed and ICA, the ICA results showed significantly higher scores than the template seed in both the patients (p = 0.01) and healthy volunteers (p = 0.005). In the quantitative analysis, the functional seed exhibited greater similarity to tbfMRI than the template seed and ICA. CONCLUSION: Using the contralateral motor cortex determined by tbfMRI as a seed could enhance visual delineation of the motor cortex in seed-based rsfMRI.

Basics of Electroencephalography for Neuropsychiatrist / 신경정신의학

In 1924, Hans Berger, a German psychiatrist, recorded the brain waves from a human brain for the first time. Many advances have been made in this field since then. Currently, brain waves are generated by a variety of computer technologies, including brain computer interface technology, and robot or artificial intelligence technology has also made amazing progress. A mental health practitioner who deals with brain-related medicine has an obligation and responsibility to research and find clinical applications of brain waves because they contain a great deal of information hidden in the brain. Therefore, understanding the basics of electroencephalography will contribute to a determination and resolution of various clinical situations. This review discusses basic knowledge before dealing with brain waves. In addition to a visual inspection of general brain waves, quantitative analysis of brain waves is expected to become an important area of interest for mental health practitioners.

Cerebral small vessel disease and cognitive impairment: the significance of structural and functional connectivity / 国际脑血管病杂志

Cerebral small vessel disease (CSVD) is the leading cause of cognitive decline in the elderly. Neuroimaging studies have shown that there are structural and functional connectivity abnormalities in patients with CSVD and are associated with cognitive impairment. Therefore, it is speculated that the changes of structural and functional connectivity may be an early imaging marker of CSVD-related cognitive impairment. This article reviews the significance of structural and functional connectivity in CSVD-related cognitive impairment.

Neuroanatomical Predictors of Dysphagia after Stroke: Voxel-Based Lesion Symptom Mapping Study / 대한연하장애학회지

OBJECTIVE: Dysphagia is a common consequence of stroke with a negative effect on the clinical outcome. Given these potential outcomes, it is important to identify the precursors to dysphagia after stroke. The aims of this study were to identify lesions associated with dysphagia after an ischemic supratentorial stroke using voxel-based lesion symptom mapping (VLSM) and compare the difference in the lesion pattern between the oral and pharyngeal phase dysphagia. METHODS: Stroke patients who met the following inclusion criteria were screened retrospectively between January 2012 and November 2014: a first-ever stroke, supratentorial lesion and who underwent brain MRI and functional dysphagia scale (FDS) from videofluoroscopic swallowing study (VFSS). Finally, the MRI data of 83 patients were analyzed. Statistical maps of the lesion contribution related to dysphagia were generated using VLSM. RESULTS: VLSM showed that FDS was associated with damage to the putamen, caudate, insula, frontal precentral gyrus, and inferior frontal gyrus. The lesions were distributed more widely in the left than right hemisphere. Lesions correlated with the FDS oral score were distributed mainly in the frontal lobe and insula. Otherwise, the associated lesion with the FDS pharyngeal score was mainly the basal ganglia. CONCLUSION: In these results, lesions that correlated with dysphagia were distributed more widely in the left hemisphere, reflecting the possibility of lateralization of the swallowing function. Oral phase dysphagia was associated with left frontal lobe and insula; the lesion correlated with the cognitive function or apraxia. On the other hand, VLSM revealed the lesions associated with pharyngeal dysphagia to be the basal ganglia, which is a structure that plays a role in the automatic motor control network.

Expression of protein phosphatase 2AC in the brain of mice and Alzheimer′s patients / 中华病理学杂志

Objective@#To investigate the biological functions of protein phosphatase 2AC(PP2AC) in the brain, and to detect its spatio-temporal expression and its involvement in neurological disorders in the brains of mice and Alzheimer′s patients.@*Methods@#Western blot was used to evaluate the expression level of PP2AC in different organs. Immunohistochemical staining was performed to detect the in situ expression levels of PP2AC in the brains of mice and patients, and the pathological changes were confirmed in the brains of patients with Alzheimer′s disease.@*Results@#Among all the tested organs in adult mouse, the expression of PP2AC protein was the highest in the brain. From embryonic day 18.5 to postnatal 2-year-old mice, PP2AC exhibited spatio-temporal specific expression in the brains. Furthermore, an age-dependent increased expression in the cerebral cortex at both protein and RNA levels was observed. Compared to control group, PP2AC protein expression was lower in the frontal cortex of Alzheimer′s patients.@*Conclusions@#The spatio-temporal specific expression profiles of PP2AC in mouse brain implicate its biological significance. Its diminished expression in the frontal cortex of Alzheimer′s disease patients implies that PP2AC plays a potential role in the pathogenesis of Alzheimer′s disease.

Multimode magnetic resonance imaging of leukoaraiosis / 国际脑血管病杂志

Leukoariaosis, or white matter lesions, are characterized by bilateral, mostly symmetrical hyperintensities on T 2-weighted imaging and fluid-attenuated inversion recovery MRI, and are associated with an increased risk of stroke, dementia, and cognitive decline. This article reiews multimode magnetic resonance imaging of leukoaraiosis, including structural and functional magnetic resonance imaging.

Interictal abnormal fMRI activation of visual areas during a motor task cued by visual stimuli in migraine / Ativação interictal anormal de áreas visuais por ressonância magnética funcional durante uma tarefa visuo-motora em indivíduos com enxaqueca

ABSTRACT Objective To assess changes in blood-oxygen-level-dependent activity after light deprivation compared to regular light exposure in subjects with migraine in the interictal state and in controls. Methods Ten subjects with migraine and ten controls participated in two sessions of functional magnetic resonance imaging. In each session, they performed a finger-tapping task with the right hand, cued by visual stimuli. They were scanned before and after 30 minutes of light deprivation or light exposure. In subjects with migraine, functional magnetic resonance imaging was performed interictally. Analysis of variance was made with the factors time (before or after), session (light deprivation or exposure), and group (migraine or control). Results There were significant “group” effects in a cluster in the bilateral cuneus encompassing the superior border of the calcarine sulcus and extrastriate cortex. There were no significant effects of “time”, “session”, or interactions between these factors. Conclusion The main result of this study is consistent with aberrant interictal processing of visual information in migraine. Light deprivation did not modulate functional magnetic resonance imaging activity in subjects with or without migraine.

RESUMO Objetivo Avaliar mudanças na atividade cerebral por meio de ressonância magnética funcional após privação luminosa comparada à exposição à luz, em indivíduos com enxaqueca no estado interictal e em controles. Métodos Dez indivíduos com enxaqueca e dez controles participaram de duas sessões de ressonância magnética funcional. Em cada sessão, realizaram uma tarefa motora com a mão direita guiada por estímulos visuais. Foram colhidas imagens antes e após 30 minutos de privação luminosa ou exposição à luz. Em indivíduos com enxaqueca, a ressonância funcional foi realizada no período interictal. Foi feita a análise de variância com fatores tempo (antes ou depois), sessão (privação ou exposição à luz) e grupo (enxaqueca ou controle). Resultados Houve efeitos significativos de “grupo” em uma área no cúneo bilateral, incluindo a borda superior do sulco calcarino e o córtex extraestriado. Não houve efeitos significativos de “tempo”, “sessão” ou interações entre estes fatores. Conclusão O principal resultado deste estudo sugere um processamento interictal anormal das informações visuais em indivíduos com enxaqueca. A privação luminosa não modulou a atividade na ressonância magnética funcional em indivíduos com ou sem enxaqueca.

Up-to-date viewpoint of cerebral glioma surgery / 复旦学报（医学版）

Today,the primary goal of cerebral glioma surgery is to achieve maximum safe resection.The cytoreductive surgery ensures the sensitivity to postoperative radiotherapy,chemotherapy (targeted therapy) and immunotherapy and other individualized adjuvant treatment,while limits sacrifice of the quality of life of patients.Comprehensive use of neuronavigation,iMRI intraoperative real-time image guidance,multimodal functional and metabolic image guidance,intraoperative fluorescence technology,awake craniotomy and intraoperative electrophysiological monitoring and other new technologies to achieve accurate positioning of multi-mode brain function,real-time protection and quantitative control of extent of tumor resection,are not only achieving the promising goal of cerebral glioma surgeries,but enhancing the realization of the China Brain Project.

We Must Invest in Applied Knowledge of Computational Neurosciences and Neuroinformatics as an Important Future in Malaysia: The Malaysian Brain Mapping Project

The Academy of Sciences Malaysia and the Malaysian Industry-Government group for High Technology has been working hard to project the future of big data and neurotechnology usage up to the year 2050. On the 19 September 2016, the International Brain Initiative was announced by US Under Secretary of State Thomas Shannon at a meeting that accompanied the United Nations’ General Assembly in New York City. This initiative was seen as an important effort but deemed costly for developing countries. At a concurrent meeting hosted by the US National Science Foundation at Rockefeller University, numerous countries discussed this massive project, which would require genuine collaboration between investigators in the realms of neuroethics. Malaysia’s readiness to embark on using big data in the field of brain, mind and neurosciences is to prepare for the 4th Industrial Revolution which is an important investment for the country’s future. The development of new strategies has also been encouraged by the involvement of the Society of Brain Mapping and Therapeutics, USA and the International Neuroinformatics Coordinating Facility.

Causes, effects and connectivity changes in MS-related cognitive decline / Causas, efeitos e alterações de conectividade no declínio relacionado à esclerose múltipla

Cognitive decline is a frequent but undervalued aspect of multiple sclerosis (MS). Currently, it remains unclear what the strongest determinants of cognitive dysfunction are, with grey matter damage most directly related to cognitive impairment. Multi-parametric studies seem to indicate that individual factors of MS-pathology are highly interdependent causes of grey matter atrophy and permanent brain damage. They are associated with intermediate functional effects (e.g. in functional MRI) representing a balance between disconnection and (mal) adaptive connectivity changes. Therefore, a more comprehensive MRI approach is warranted, aiming to link structural changes with functional brain organization. To better understand the disconnection syndromes and cognitive decline in MS, this paper reviews the associations between MRI metrics and cognitive performance, by discussing the interactions between multiple facets of MS pathology as determinants of brain damage and how they affect network efficiency.

Declínio cognitivo é uma situação frequente mas ainda pouco compreendida na esclerose múltipla (EM). Atualmente, não são totalmente conhecidos os principais determinantes da disfunção cognitiva na doença, tendo sido apontadas fortes associações entre danos à substância cinzenta e declínio cognitivo. Estudos multiparamétricos mostram que os diferentes fatores patológicos da EM participam como causas interdependentes de atrofia da substância cinzenta e dano cerebral permanente. Eles são associados a efeitos funcionais intermediários (detectados por RM funcional) representando um equilíbrio entre desconexão cerebral e alterações (mal) adaptativas. Portanto, uma abordagem de imagem mais abrangente é necessária, com o objetivo de encontrar associações entre alterações estruturais e a organização funcional cerebral. Para melhor compreender o declínio cognitivo na EM, esse artigo propões uma revisão dos principais métodos de imagem por RM e suas correlações com função cognitiva, discutindo as múltiplas faces patológicas da EM e seu impacto na eficiência das redes neurais.

Alpha power oscillation in the frontal cortex under Bromazepam and Modafinil effects / Oscilações da potência alfa no córtex frontal sob influência do Bromazepam e Modafinil

ABSTRACTObjective Our aim was to investigate and compare the neuromodulatory effects of bromazepam (6 mg) and modafinil (200 mg) during a sensorimotor task analyzing the changes produced in the absolute alpha power.Method The sample was composed of 15 healthy individuals exposed to three experimental conditions: placebo, modafinil and bromazepam. EEG data were recorded before, during and after the execution of the task. A three-way ANOVA was applied, in order to compare the absolute alpha power among the factors: Group (control, bromazepam and modafinil) Condition (Pre and Post-drug ingestion) and Moment (pre and post-stimulus).Results Interaction was found between the group and condition factors for Fp1, F4 and F3. We observed a main effect of moment and condition for the Fp2, F8 and Fz electrodes.Conclusion We concluded that drugs may interfere in sensorimotor processes, such as in the performance of tasks carried out in an unpredictable scenario.

RESUMOObjetivo Investigar e comparar os efeitos neuromoduladores do bromazepam (6mg) e modafinil (200mg), durante a prática de uma tarefa sensoriomotora, analisando as modificações produzidas na potência absoluta de alfa.Método A amostra foi composta por 15 indivíduos saudáveis, expostos a três condições experimentais: Placebo, modafinil e bromazepam. Dados eletroencefalográficos foram registrados antes, durante e após a execução da tarefa motora. Um ANOVA three-way foi aplicado para comparar a potência absoluta de alfa nos fatores Grupo (controle, bromazepam e modafinil), Condição (Pré e Pós ingestão da droga) e Momento (Pré e Pós estimulo).Resultados Verificou-se interação entre os fatores grupo e condição para os eletrodos Fp1, F4 e F3. Observamos um efeito principal para momento e condição nos eletrodos Fp2, F8 e Fz.Conclusão Concluímos que as drogas, podem interferir em processos sensoriomotores, como no desempenho de tarefas executadas em um cenário imprevisível.

Evaluación de estructuras cerebrales por resonancia magnética en personas infectadas con el virus de la inmunodeficiencia humana (VIH) y adherentes al tratamiento antirretroviral / Evaluation by MRI of brain structures of HIV subjects with adherence to antiretroviral therapy

Introducción: los cambios estructurales del cerebro se pueden observar en fases tempranas de la infección por VIH y acelerarse en estadios avanzados, aunque queda por profundizar con más estudios clínicos la relación que pueda existir entre la adherencia al tratamiento antirretroviral y los cambios en los volúmenes de las estructuras cerebrales. Objetivo: identificar los cambios en estructurascerebrales de personas infectadas con VIH por medio de la resonancia magnética y explorar su relación con el tratamiento antirretroviral. Materiales y métodos: se eligieron 2 grupos, cada uno con 16 individuos; el primero conformado por personas infectadas con VIH y tratamiento adherente y el segundo con individuos no infectados (grupo control). Los volúmenes de las estructuras corticales, subcorticales, las regiones superficiales de la sustancia blanca y gris fueron calculados para los dos hemisferios, en los cuales se utilizaron algoritmos automáticos de la plataforma de análisis de imágenesFreeSurfer. Los datos anatómicos de los individuos fueron adquiridos en un equipo de resonancia magnética 3T en el Instituto de Alta Tecnología Médica (IATM), Medellín, Colombia. Resultados: el análisis de las estructuras corticales y subcorticales no arrojó diferencias significativas entre las volumetríasdel grupo control y los individuos infectados con VIH/adherentes al tratamiento. Conclusión: los hallazgos muestran que el cerebro puede estar posiblemente sin alteraciones en sus estructuras corticales y subcorticales en los individuos con VIH adherentes al tratamiento, en primera o segunda línea de tratamiento antirretroviral, y, a la vez, estos resultados pueden aportar nuevas estrategias de neuroprotección ante el autocuidado frente al esquema de tratamento.

Introduction: structural brain changes can be detected in early stages of HIV infection and may be accelerated in advanced stages, however it still important to have more clinic studies for analyze the relationship between the adherence to antiretroviral therapy and changes in the volume of brain structures. Objective: To identify changes in brain structures from HIV subjects by using Magnetic Resonance Imaging (MRI) and to correlate the findings with the antiretroviral treatment. Materials and methods: Two groups with 16 subjects were chosen: a HIV group of subjects with medication adherence and healthy subjects (control group). By using the automatic segmentation software for brain Freesurfer, cortical and subcortical structures volumes as well as grey and white matter surface area were calculated for both brain hemispheres. Data were acquired through 3T MRI scanner in the Instituto de Alta Tecnología Médica (IATM) from Medellin (Colombia). Results: There were not statistically significant differences in cortical and subcortical structures between control group and subjects HIV infected with adherence to treatment. Conclusion: These findings show that subjects infectedwith VIH in first or second line of antiretroviral treatment probably do not have any change on the brain cortical and subcortical structures. In addition, this allows developing new neuroprotection and self-care strategies during the current treatment plans.

Functional Neuroimaging of Tinnitus: State-of-the-Art / 대한이비인후과학회지

Non-pulsatile subjective tinnitus is a phantom sound percept without any objective physical sound source. Recent advances in tinnitus research have suggested central rather than peripheral changes as the culprit of tinnitus perception. Moreover, researchers have shown that these central functional changes can be observed not only in the auditory cortex but also in non-auditory regions such as the frontal, parietal, and limbic areas in patients with tinnitus. In this regard, functional neuroimaging modalities such as positron emission tomography (PET), functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and quantitative electroencephalography (qEEG) provided researchers with a window into the cerebral cortical activity orchestrating tinnitus. Among these methods, qEEG and MEG are advantageous over PET or fMRI with regard to temporal resolution, while PET and fMRI are advantageous over qEEG or MEG with regard to spatial resolution. In other words, there is no gold standard functional neuroimaging modality in the field of tinnitus, but these four modalities are complementary to one another. In this review article, these four representative functional neuroimaging modalities and their application to tinnitus research will be introduced. Moreover, future direction of functional neuroimaging research on the pathophysiology of tinnitus will be discussed briefly.

Funcionamento cerebral de repouso em idosos e recuperação de memória autobiográfica: um estudo de ressonância magnética funcional / Brain function at rest and recovery of autobiographical memory in the elderly: a functional magnetic resonance imaging study

INTRODUÇÃO: As bases neurofisiológicas do declínio cognitivo associado ao envelhecimento normal ainda não são adequadamente conhecidas. Estudos sobre conectividade funcional cerebral estimada através de imagens por ressonância magnética funcional durante o repouso têm identificado diminuições de conectividade dentro da rede de modo padrão (default mode network) em idosos e correlações entre desempenho cognitivo e conectividade funcional. Há evidências de que idosos apresentam maior dificuldade em recuperar informações episódicas de eventos autobiográficos mas não existem investigações sobre a relação entre tal função cognitiva e conectividade de repouso. Além disso, estudos desta área geralmente não têm utilizado entrevista psiquiátrica para seleção da amostra, apesar de transtornos psiquiátricos apresentarem alta prevalência, serem subdiagnosticados e afetarem o funcionamento cerebral. OBJETIVOS: caracterizar as mudanças de conectividade funcional de repouso associadas a idade e a desempenho cognitivo, em especial à função de memória autobiográfica, em uma amostra de adultos de diferentes idades e livres de deficiências cognitivas e de transtornos psiquiátricos. MÉTODOS: adultos jovens, de meia idade e idosos sem transtornos cognitivos ou psiquiátricos foram selecionados através de avaliação neuropsicológica e entrevista psiquiátrica estruturada. Quantificamos o desempenho em recuperar informações episódicas de eventos autobiográficos. Conectividade funcional cerebral foi estimada a partir de imagens de ressonância magnética funcional adquiridas durante o repouso vigil, utilizando um atlas de 278 regiões englobando todo o cérebro. As relações entre conectividade e idade e conectividade e desempenho cognitivo foram avaliadas através do método dos quadrados parciais mínimos. RESULTADOS: em uma amostra de 59 adultos (19 jovens, 20 de meia idade e 20 idosos), idade apresentou correlação negativa com desempenho cognitivo geral, mas sua relação com memória...

INTRODUCTION: The neurophysiological basis of the cognitive decline associated with aging is not yet known. Brain functional connectivity studies using functional magnetic resonance images acquired during rest have shown that aging is associated with decreases in connectivity within the default mode network. Moreover, cognitive performance has been associated with resting functional connectivity. There is evidence that older adults present worse performance during retrieval of episodic information from autobiographical events but there is no investigation regarding the relationship between functional connectivity at rest and this cognitive function. Moreover, studies in this field have not applied a structured psychiatric interview to select the sample, although it is known that psychiatric disorders present high prevalence, are underdiagnosed and are associated with functional abnormalities. OBJECTIVES: to characterize changes in resting-state functional connectivity associated with age and cognitive performance, especially with autobiographical memory, in adults from different ages, free of cognitive deficits and psychiatric disorders. METHODS: using a neuropsychological evaluation and a structured psychiatric interview we selected a sample of young, middle aged and elderly adults free of cognitive and psychiatric disorders. We measured the performance to recover episodic information from autobiographical events. Brain functional connectivity was estimated from resting-state functional magnetic resonance images acquired during rest, using a whole-brain 278-region atlas. We used partial least squares to characterize the relationships between connectivity and age and connectivity and cognitive performance. RESULTS: in a sample of 59 adults (19 young, 20 middle aged and 20 elderly), age was negatively correlated with general cognitive performance but its relationship with autobiographical memory was not statistically significant. The pattern of...

Analysis on Bilateral Hindlimb Mapping in Motor Cortex of the Rat by an Intracortical Microstimulation Method

Intracortical microstimulation (ICMS) is a technique that was developed to derive movement representation of the motor cortex. Although rats are now commonly used in motor mapping studies, the precise characteristics of rat motor map, including symmetry and consistency across animals, and the possibility of repeated stimulation have not yet been established. We performed bilateral hindlimb mapping of motor cortex in six Sprague-Dawley rats using ICMS. ICMS was applied to the left and the right cerebral hemisphere at 0.3 mm intervals vertically and horizontally from the bregma, and any movement of the hindlimbs was noted. The majority (80%+/-11%) of responses were not restricted to a single joint, which occurred simultaneously at two or three hindlimb joints. The size and shape of hindlimb motor cortex was variable among rats, but existed on the convex side of the cerebral hemisphere in all rats. The results did not show symmetry according to specific joints in each rats. Conclusively, the hindlimb representation in the rat motor cortex was conveniently mapped using ICMS, but the characteristics and inter-individual variability suggest that precise individual mapping is needed to clarify motor distribution in rats.

Value of afterdischarges monitoring for intraoperative electrical stimulation for brain mapping / 实用医学杂志

Objective To explore the value of afterdischarges monitoring for intraoperative electrical stimulation for brain mapping. Methods 34 patients received cerebral cortex electrical stimulation for brain mapping during operation of brain function area , afterdischarges were monitored simultaneously to determine the upper limit of stimulus intensity. Results 34 cases underwent electrical stimulation successfully , and received surgery without neurologic decline except 2 cases of hypokinesia. Conclusion After discharges monitoring improve the accuracy, reduce the risk of intraoperative cerebral cortex electrical stimulation.