Volumetric Assessment of the Insula in a Normally Functioning Human Brain Using Magnetic Resonance Imaging / Evaluación Volumétrica de la Ínsula en un Cerebro Humano que Funciona Normalmente Utilizando Imágenes de Resonancia Magnética

SUMMARY: Volumetric assessment of brain structures is an important tool in neuroscience research and clinical practice. The volumetric measurement of normally functioning human brain helps detect age-related changes in some regions, which can be observed at varying degrees. This study aims to estimate the insular volume in the normally functioning human brain in both genders, different age groups, and side variations. A cross-sectional retrospective study was conducted on 42 adult Sudanese participants in Al-Amal Hospital, Sudan, between May to August 2022, using magnetic resonance imaging (MRI) and automatic brain segmentation through a software program (BrainSuite). The statistical difference in total insular volume on both sides of the cerebral hemisphere was small. The insular volume on the right side was greater in males, while the left side showed no difference between both genders. A statistically significant difference between males and females was found (p > 0.05), and no statistical difference in different age groups was found according to the one-way ANOVA test (p>0.05). Adult Sudanese males showed a larger insular volume than females. MRI can be used to morphometrically assess the insula to detect any pathological variations based on volume changes.

La evaluación volumétrica de las estructuras cerebrales es una herramienta importante en la investigación y la práctica clínica de la neurociencia. La medición volumétrica del cerebro humano, que funciona normalmente, ayuda a detectar cambios relacionados con la edad en algunas regiones, las cuales se pueden observar en diversos grados. Este estudio tuvo como objetivo estimar el volumen insular en el cerebro humano que funciona normalmente, en ambos sexos, de diferentes grupos de edad y sus variaciones laterales. Se realizó un estudio retrospectivo transversal en 42 participantes sudaneses adultos en el Hospital Al-Amal, Sudán, entre mayo y agosto de 2022, utilizando imágenes de resonancia magnética y segmentación automática del cerebro a través de un software (BrainSuite). Fue pequeña la diferencia estadística en el volumen insular total, en los hemisferios cerebrales. El volumen insular del lado derecho fue mayor en los hombres, mientras que el lado izquierdo no mostró diferencia entre ambos sexos. Se encontró una diferencia estadísticamente significativa entre hombres y mujeres (p > 0,05), y no se encontró diferencia estadística en los diferentes grupos de edad, según la prueba de ANOVA de una vía (p> 0,05). Los hombres sudaneses adultos mostraron un mayor volumen insular que las mujeres. La resonancia magnética se puede utilizar para evaluar morfométricamente la ínsula y para detectar cualquier variación patológica basada en cambios de volumen.

Subthalamic Nucleus: Neuroanatomical Review

Discovered in 1865 by Jules Bernard Luys, the subthalamic nucleus is a set of small nuclei located in the diencephalon, inferior to the thalamus and superior to the substantia nigra, that can be visualized in a posterior coronal section. Histologically, it consists of neurons compactly distributed and filled with a large number of blood vessels and sparse myelinated fibers. This review presents an analysis of this anatomical region, considering what is most recent in the literature. Subthalamic neurons are excitatory and use glutamate as the neurotransmitter. In healthy individuals, these neurons are inhibited by nerve cells located in the side globus pallidus. However, if the fibers that make up the afferent circuit are damaged, the neurons become highly excitable, thus causing motor disturbances that can be classified as hyperkinetic, for example ballism and chorea, or hypokinetic, for example Parkinson disease (PD). The advent of deep brain stimulation has given the subthalamic nucleus great visibility. Studies reveal that the stimulation of this nucleus improves themotor symptoms of PD.

Cerebral localization of higher functions: anatomic structures before the identification of their memory function / Localização cerebral de funções superiores: estruturas anatômicas antes da identificação de suas funções de memória

The nature of memory and the search for its localization have been a subject of interest since Antiquity. After millennia of hypothetical concepts the core memory-related structures finally began to be identified through modern scientifically-based methods at the diencephalic, hippocampal, and neocortical levels. However, there was a clear temporal delay between the finding of these anatomic structures ignoring their function, and their identification related to memory function. Thus, the core structures begun to be identified with a pure anatomical view in the late Middle Ages on, while the memory function related to them was discovered much later, in the late Modern Period.

A natureza da memória e a busca de sua localização tem sido objeto de interesse desde a Antiguidade. Após milênios de conceitos hipotéticos as estruturas centrais relacionadas com a memória finalmente começaram a ser identificadas através de métodos modernos com base científica, nos níveis diencefálico, hipocampal e neocortical. Entretanto, houve um claro retardo temporal entre o achado dessas estruturas anatômicas ignorando sua função e sua identificação relacionada à função da memória. Assim, as estruturas centrais começaram a ser identificadas com uma visão puramente anatômica da Idade Média tardia em diante, enquanto a função da memória relacionada com as mesmas foi descoberta muito mais tarde, no Período Moderno tardio.

Morphological relationship between the superficial cortical and deep grey matter structures in adult human brains: a cadaveric study / Relación morfológica entre las estructuras superficiales de la sustancia gris cortical y profunda en los cerebros humanos adultos: un estudio en cadáveres

While various neurodegenerative diseases affect cortical mass differently, finding an optimal and accurate method for measuring the thickness and surface area of cerebral cortex remains a challenging problem due to highly convoluted surface of the cortex. We therefore investigated cortical thickness in a sample of cadaveric specimens at the Discipline of Clinical Anatomy, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, South Africa to provide some clue as to possible variations in the parameters. Following ethical approval, 60 brain samples were uniformly sectioned (5 mm thickness) and eight slices taken from each brain across regions of interest (ROI) prepared and stained by Mulligan's technique. Thickness was measured at selected angles (0º, 45º, 90º, 135º and 180º) for both right and left cerebral hemispheres. Mulligan's stain produced good cortical differentiation and clear images that enabled manual delineation of structures. Cortical thickness ranged from 3 to 5 millimeters across the ROI. Interestingly, there was rightward hemispheric asymmetry of cortical thickness of selective slices at suggested angles which is related to structurally and functionally important brain regions. Moreover, there was no significant correlation between the surface area of superficial cortex and the deep nuclei at the same level. The superficial cortex and deep nuclei are manifested independently in normal aging, neuropsychiatric or developmental disorders. Providing accurate morphometric evaluation of cortical thickness and area based on gross staining of the brain slices could provide qualitative data that may support the study of human cerebral cortex even in disease conditions.

Si bien varias enfermedades neurodegenerativas afectan a la masa cortical de manera diferente, encontrar un método óptimo y preciso para medir el grosor y el área de la superficie de la corteza cerebral sigue siendo un problema difícil debido a la superficie altamente enrevesada de la corteza. Por lo tanto, investigamos el grosor cortical en una muestra de cadáveres del Departamento de Anatomía Clínica de la Facultad de Medicina Nelson R. Mandela de la Universidad de KwaZulu-Natal, Sudáfrica, para proporcionar alguna pista sobre posibles variaciones en dichos parámetros. Después de la aprobación ética, 60 muestras de cerebro se seccionaron uniformemente (5 mm de grosor) y se tomaron ocho cortes de cada cerebro en regiones de interés (ROI) preparadas y teñidas con la técnica de Mulligan. El espesor se midió en los ángulos seleccionados (0º, 45º, 90º, 135º y 180º) para los hemisferios cerebrales derecho e izquierdo. La tinción de Mulligan produjo una buena diferenciación cortical e imágenes claras que permitieron la delineación manual de las estructuras. El grosor cortical osciló entre 3 y 5 milímetros a través del ROI. Curiosamente, hubo una asimetría hemisférica hacia la derecha del grosor cortical de los cortes en ángulos sugeridos que se relacionan con regiones cerebrales estructural y funcionalmente importantes. Además, no hubo una correlación significativa entre el área de la superficial de la corteza superficial y los núcleos profundos en el mismo nivel. La corteza superficial y los núcleos profundos se manifiestan de manera independiente en el envejecimiento normal, en los trastornos neuropsiquiátricos o del desarrollo. Realizar una evaluación morfométrica precisa del grosorcortical y el área basada en la tinción macroscópica de los cortes del cerebro, podría proporcionar datos cualitativos que puedan respaldar el estudio de la corteza cerebral humana incluso en condiciones de enfermedad.

Anatomía, fisiología y rol clínico de la corteza vestibular / Anatomy, physiology and clinical role of the vestibular cortex

El sistema vestibular, mediante sus órganos periféricos, nos permite procesar correctamente los cambios de aceleración angular de la cabeza y lineal del cuerpo y así permitirnos una correcta orientación en el espacio. Esta información sensorial es dirigida hacia los núcleos vestibulares y desde aquí se comunica con los núcleos óculo-motores y estructuras del tálamo a través de tractos ascendentes del tronco encefálico. Posteriormente la información se dirige hacia centros subcorticales y corticales de naturaleza eminentemente multisensorial. La naturaleza y función de estas estructuras es controversial. En esta revisión se abordan los principales conceptos y descubrimientos a nivel de investigación básica y clínica del procesamiento cortical generado por estimulación de tipo vestibular.

The vestibular system, thanks to its peripheral organs, allows us to properly process the angular head movements and linear acceleration in order to give us a proper orientation in space. The information from these sensory inputs is routed to the vestibular nuclei and thence ascending tracts of the brainstem, which communicate with the oculomotor nuclei of the thalamus and structures. Then the information goes to subcortical and cortical centers, which are eminently multisensory nature. The nature and function of these structures are controversial. In this review the main concepts and discoveries at the level of basic and clinical research generated cortical processing of vestibular stimulation are addressed.

La Insulectomía podría ser un abordaje ideal para crisis insulares y peri-insulares? / Insulectomy for insular and peri-insular seizures could be an ideal and safe approach?

La insulectomía es una técnica microquirúrgica establecida para el tratamiento de la epilepsia refractaria al tratamiento farmacológico. El origen insular de la epilepsia es inusual, sin embargo, con la investigación a través de electrodos híbridos este tipo de epilepsia ha incrementado su diagnóstico. Los autores hacen hincapié en las funciones insulares, así como los puntos de referencia anatómicos para la cirugía. Se discuten las principales complicaciones y las bases fisiológicas para las indicaciones de cirugía.

Insulectomy is an established microsurgical technique for treatment of insular epilepsy refractory to clinical management. The insular origin of epilepsy is unusual, however with depth investigation through hybrids electrodes such kind of epilepsy is increasing its diagnosis. The authors emphasizes the insular functions as well as the anatomical landmarks for surgery. The main complications are discussed and physiological basis for indications.

Anatomía microquirúrgica en 3D de la superficie cerebral / Microsurgical anatomy in 3D of the brain cortex

Introducción: El estudio de la superficie externa del cerebro es analizado desde diferentes puntos espaciales, es decir unasuperficie lateral, medial y basal. La superficie lateral del cerebro se distingue por la presencia de dos puntos de referencia quedividen a cada hemisferio cerebral en lóbulos. Estos dos puntos son la fisura de Silvio (fisura lateral) y el surco de Rolando (surcocentral). Estos dos surcos dividen a cada hemisferio en lóbulo frontal (superior a la fisura de Silvio y anterior al surco de Rolando),el lóbulo temporal (inferior a la fisura de Silvio) y lóbulo parietal (superior a la fisura de Silvio y posterior al surco de Rolando). Ellóbulo occipital se ubica por detrás del surco parietooccipital, y el lóbulo de la ínsula que se sitúa en la profundidad de la fisurade Silvio. Objetivo: Describir la anatomía Microquirúrgica de la superficie cerebral en imágenes estereoscópicas anaglíficas tridimensionales.Material y Métodos: La superficie cerebral fue examinada en 30 cerebros humanos con la ayuda de microscopioquirúrgico D.F. Vasconcellos M900 con una magnificación de 16x y 40x, el equipo fotográfico marca Nikon modelo D60, lenteAF-S VR Micro-Nikkor 105 mm f/2.8G IF-ED de Nikon, instrumental de microcirugía y sistema de vernier calibrado en décimasde milímetros. Resultados: La superficie cerebral de cada hemisferio esta dividida por medio de la fisura de Silvio y el surco deRolando en; Lóbulo frontal que se localiza superior a la fisura de Silvio y anterior al surco de Rolando, el lóbulo temporal que sesitúa inferior a la fisura de Silvio, lóbulo parietal de localización superior a la fisura de Silvio y posterior al surco de Rolando, el lóbulooccipital se ubica por detrás del surco parietooccipital. En la profundidad de la fisura de Silvio se encuentra el lóbulo de la ínsula...

Introduction: Brain cortex is studied from different views: lateral, medial and basal surfaces. The brain lateral surface is distinguished by the presence of referential points and sulci. Those specific surgical points consist of the Sylvian fissure (lateral fissure) and the Rolandic sulcus (central sulcus). Those sulci divide each hemisphere in frontal lobe (superior to the Sylvian fissure and anterior to the Rolandic sulcus), temporal lobe (inferior to the Sylvian fissure), and parietal lobe (superior to the Sylvian fissure and posterior to the Rolandic sulcus). The occipital lobe is located posteriorly to the parietooccipital sulci, and the insular lobe is located deep into the Sylvian fissure. Objetive: To describe the microsurgical anatomy of the brain cortex in tridimensional surface imaging reconstruction. Material and Methods: Human cadaveric speciments of 30 human brains were studied through the surgical microscopy D.F. Vasconcellos M900, 16x and 40x magnification, Nikon D60 camera, AF-S VR Micro-Nikkor 105 mm f/2.8G IF-ED lens, and microsurgical instruments. Results: Brain surface is divided in each hemisphere basically through the Sylvian fissure and the Rolandic sulcus in frontal lobe, superiorly to the to the Sylvian fissure and anteriorly to the Rolandic sulcus, temporal lobe, inferiorly to the Sylvian fissure, parietal lobe, superiorly to the Sylvian fissure and posteriorly to the Rolandic sulci, and occipital lobe behind the parietooccipital sulci. Deep into the Sylvian fissure is located the insular lobe...

Cerebellar anatomy as applied to cerebellar microsurgical resections / Anatomia cerebelar aplicada à microcirurgia cerebelar ablativa

OBJECTIVE: To define the anatomy of dentate nucleus and cerebellar peduncles, demonstrating the surgical application of anatomic landmarks in cerebellar resections. METHODS: Twenty cerebellar hemispheres were studied. RESULTS: The majority of dentate nucleus and cerebellar peduncles had demonstrated constant relationship to other cerebellar structures, which provided landmarks for surgical approaching. The lateral border is separated from the midline by 19.5 mm in both hemispheres. The posterior border of the cortex is separated 23.3 mm from the posterior segment of the dentate nucleus; the lateral one is separated 26 mm from the lateral border of the nucleus; and the posterior segment of the dentate nucleus is separated 25.4 mm from the posterolateral angle formed by the junction of lateral and posterior borders of cerebellar hemisphere. CONCLUSIONS: Microsurgical anatomy has provided important landmarks that could be applied to cerebellar surgical resections.

OBJETIVO: Definir a anatomia do núcleo denteado e dos pedúnculos cerebelares, demonstrando a aplicação dos marcos anatômicos em cirurgias cerebelares. MÉTODOS: Foram estudados 20 hemisférios cerebelares. RESULTADOS: A maioria dos núcleos denteados e pedúnculos cerebelares demonstraram relação anatômica constante com outras estruturas cerebelares, fato que proporcionou o estabelecimento de marcos anatômicos específicos a serem utilizados em acessos cirúrgicos. O bordo lateral do núcleo denteado é separado da linha média em 19,5 mm em ambos os hemisférios cerebelares. O bordo posterior do córtex é separado do segmento posterior do núcleo denteado por 23,3 mm. O bordo lateral do córtex é separado do bordo lateral do núcleo por 26 mm e o segmento posterior do núcleo denteado é separado por 25,4 mm do ângulo posterolateral, que é formado pela junção dos bordos lateral e posterior do hemisfério cerebelar. CONCLUSÕES: O estudo da anatomia microcirúrgica proporcionou o estabelecimento de marcos anatômicos importantes que podem ser utilizados durante cirurgias cerebelares ablativas.

La representación neurobiológica de las palabras y sus significados en el cerebro / Neurobiological representation of words and their meanings in the brain

Durante mucho tiempo, la principal fuente de información para entender cómo se organiza el lenguaje en el cerebro fueron los estudios neuropsicológicos. Sin embargo, las técnicas avanzadas de neuroimágenes y electrofisiología proporcionan nuevos datos sobre el procesamiento lingüístico en los cerebros intactos, mostrando que los procesos del lenguaje parecen estar mucho más ampliamente distribuidos de lo pensado hasta entonces. Este artículo revisa la información reciente sobre la organización neurobiológica de las palabras y sus significados. Los datos actuales sugieren que las palabras se extienden corticalmente como redes de neuronas con diferentes topografías corticales que reflejan su significado, o más exactamente, aspectos de su referencia. Por ejemplo, diferentes subcategorías de palabras de acción dan lugar a diferentes respuestas cerebrales. Así, encontramos que leer palabras relacionadas con el olor, tales como “canela”, “ajo” o “jazmín”, causa activación en el cortex olfativo primario, y la lectura de palabras relacionadas con el sabor, tales como “sal” o “miel”, activa regiones cerebrales del gusto. Estos y otros datos indican que el significado de una palabra no está confinado a una región específica del cerebro; por el contrario, parece probable que las representaciones semánticas se encuentren distribuidas de un modo sistemático a través de todo el cerebro, incorporando información sensorial y motora

Comparação do número de corpos de neurônios em diferentes giros do córtex cerebral de cães desnutridos / Comparison of the neuron bodies number in different gyrus of brain cortex of malnourished dogs

Este trabalho teve por objetivo estudar possíveis alterações quantitativas em corpos de neurônios do córtex cerebral de cães, causadas pela desnutrição. Foram utilizados sete encéfalos de cães machos sem raça definida, diagnosticados desnutridos, para a realização deste estudo. Foram definidos diferentes giros do córtex cerebral a serem estudados; estes foram amostrados, processados pelo procedimento histológico de rotina e corados pelo método de violeta cresil modificado, para visualização dos corpos de neurônios. As lâminas foram analisadas à ocular de 20 vezes. Os resultados obtidos revelaram uma diminuição expressiva na quantidade de corpos de neurônios nos cães desnutridos (10,8), quando comparados aos cães normonutridos (16,35), concluindo que possivelmente a desnutrição é um fator de diminuição do número de corpos de neurônios no córtex cerebral de cães desnutridos, quando comparados a normonutridos.

The aim of this study was to verify the quantitative alterations of the neurons bodies in the brain cortex of malnourished dogs. Seven brains of mongrel male dogs that were previously diagnosticated as malnourished were collected. The dogs had similar constitutionalist characteristics of cranium (mesaquicefalus). It was chosen different gyrus of the brain cortex to been study; those gyrus were sampled, prepared according to conventional histological technique and stained by modified cresil violet, for becoming evident the neurons bodies. The slides were analyzed with the 20x ocular. Our results indicate a expressive reduction in the number of neuron bodies in malnourished dogs (10,8), when compared with dogs in normal nutrition conditions (16,35). In conclusion, it’s possible that the malnutrition leads to an reduction of neurons bodies in brain cortex of dogs, when compared to those with normal condition of nutrition.

Neuroanatomical aspects of the body awareness

The cerebral cortex is the most complex part of the human brain and is responsible for thinking, reasoning, cognitive functions, memory and sensory perception processes, among others. The cerebral cortex can be classified into areas, from the specific functions it performs. Particularly noteworthy are the cortical areas, which integrate from multimodal stimuli and enable the individual to perceive his own body and its relationship with the space around it. This capacity is built from the attitudes and values that the individual has in relation to his or her body (body image) and the dimensional perception of its segments (body schema). This process depends on complex neural mechanisms that are related to different cortical areas. The aim of this study was to compare the cortical areas involved in the construction of body perception: body image and schema. As a result, it was observed that the areas with predominance in the perception of body size are more related to the right parietal region and those related to cognitive aspects are located in the prefrontal area and parts of the limbic system.

Aspectos cuantitativos de la corteza cerebral humana / Cuantitative aspects of human cerebral cortex

Se considera a la corteza cerebral como un núcleo extendido en superficie que, como consecuencia de su tamaño, ha debido plegarse. Diversos autores dan diversas medidas del volumen cortical, que es mayor en el hemisferio derecho, probablemente por el mayor volumen de su lóbulo frontal. Otras asimetrías han sido descriptas para el plano temporal, la cisura de Silvio, el giro frontal inferiory el ventrículo lateral. El espesor cortical es variado, y para distintos autores se estima entre 1,5 y 5mm. Los datos varían de acuerdo a tamaño y edad de los individuos y con el peso cerebral total. El mayor plegamiento de la corteza cerebral se encuentra en las regiones de asociación frontal y témporo parieto occipital en ese orden.

It is assumed that the cerebral cortex is an extended nucleus that, because of its volume, has become plied. Several authors give different measures of the cortical volume. It is bigger on theright side because of the major volume of the right frontal lobe. Other assimetries have been described for the planum temporale, the silvian fissure, the inferior frontal gyrus and the lateral ventricle. The cortical thickness varies across its surface, and is estimated by different authors between 1,5 and 5mm. The data vary also after age and size of the individuals, and the total brain weight. The most plied regions are in descending order, the frontal, temporal and parieto occipital association cortices.

Densidad neuronal en la corteza visual primaria (área 17), en dos especies de octodon / Neuronal density in primary visual cortex (17 visual area), in two species of octodon

Estudios experimentales demuestran que modificaciones medioambientales pueden producir alteraciones en el desarrollo normal de la corteza cerebral visual y sus conexiones. Por otra parte, es posible que en condiciones naturales, las especies animales hayan desarrollado adaptaciones genéticas a las distintas condiciones de luminosidad en que realizan su actividad. Recientemente, se han observado variaciones significativas en la densidad neuronal cortical del área 17 (área visual primaria), en roedores silvestres con diferentes períodos diarios de actividad y relación filogenética distante (Abrothrix olivaceus y Phyllotis darwini), pero aún no se ha determinado la naturaleza genética o plástica de dichas diferencias. En este trabajo se compararon especies con una mayor cercanía filogenética, para disminuir al máximo la variable taxonómica. Se estudió la corteza visual primaria (área 17), de roedores silvestres nativos, de las especies Octodon degus (n=5) y Octodon bridgesi (n=3), pertenecientes a la Familia Octodontidae, con el propósito de evidenciar cambios a través de la medición de la densidad neuronal, mediante la técnica del disector óptico, en cortes de 40 µm, incluidos en celoidina y teñidos con Nissl. Complementariamente, se realizó una cuantificación de la densidad neuronal de la corteza motora de las especies en estudio. O. degus, que presenta un período de actividad diurna, evidenció una densidad neuronal menor en la corteza visual (34,32 +/- 2,51 x 104 neuronas/mm3), que la observada en O. bridgesi (39,55 +/- 0,64 x 104 neuronas/mm3), especie de período de actividad nocturna; lo cual fue estadísticamente significativo (t=3,44; p<0,05). Las diferencias encontradas se podrían relacionar con el tipo de condiciones de luminosidad en que se desenvuelven dichas especies, aunque no se puede descartar la influencia de otros factores.

Studies show that environmental modifications can produce profound alterations in the normal development of the visual cortex and its connectivity. For the other hand it is possible that in natural conditions, animal species have developed genetic adaptations to the different conditions of luminance in which they normally behave. Recently have observed significant changes in cortical neuronal density of area 17 (primary visual area), in two sympatric Chilean rodents with different daily activity (Phyllotis darwini and Abrothrix olivaceus), but have not yet determined the genetic nature or plastic such differences. In this paper we compared species with a closer phylogenetic relation so as to minimize the taxonomic variable. We studied the primary visual cortex (area 17) of wild rodents native of the species Octodon degus (n=5) and Octodon bridgesi (n=3), belonging to the Octodontidae family, in order to show changes in the neuronal density, using celloidin-embedded, 40µm-thickness Nissl sections, with the aid of an optical dissector. In addition, we performed a quantification of the neuronal density of the motor cortex of the species under study. O. degus, bearing a crepuscular-diurnal activity pattern, showed a lower neuronal density in the visual cortex (34.32 +/- 2.51 x10(4) neuron/mm³) than that observed in O. bridgesi (39.55 +/- 0.64 x10(4) neuron/mm³), a species that exhibits a nocturnal phase preference, which was statistically significant (t=3.44; p<0.05). These differences might be related to differences in daily activity in two species, but we cannot discount the influence of other factors.

Cortical stimulation of language fields under local anesthesia: optimizing removal of brain lesions adjacent to speech areas / Mapeamento cortical da fala com o paciente acordado: optimização para ressecção de lesões intracranianas localizadas próximas a área da fala

OBJECTIVE: The main objective when resecting benign brain lesions is to minimize risk of postoperative neurological deficits. We have assessed the safety and effectiveness of craniotomy under local anesthesia and monitored conscious sedation for the resection of lesions involving eloquent language cortex. METHODS: A retrospective review was performed on a consecutive series of 12 patients who underwent craniotomy under local anesthesia between 2001 and 2004. All patients had lesions close to the speech cortex. All resection was verified by post-operative imaging. Six subjects were male and 6 female, and were aged between 14 and 52 years. RESULTS: Lesions comprised 7 tumour lesions, 3 cavernomas and 1 dermoid cyst. Radiological gross total resection was achieved in 66 percent of patients while remaining cases had greater than 80 percent resection. Only one patient had a post-operative permanent deficit, whilst another had a transient post-operative deficit. All patients with uncontrollable epilepsy had good outcomes after surgery. None of our cases subsequently needed to be put under general anesthesia. CONCLUSION: Awake craniotomy with brain mapping is a safe technique and the "gold standard" for resection of lesions involving language areas.

OBJETIVO: O presente estudo visa discutir as vantagens e as limitacões do uso da técnica de mapeamento cortical da área da fala com o paciente acordado. MÉTODO: esta é uma revisão retrospectiva dos casos em que foi realizado monitoramento cortical intraoperatório em cirurgias para ressecção de lesões intracranianas localizadas próximas à área da fala. Todos os pacientes foram submetidos a avaliação neuropsicológica no pré e intra-operatório. O grau das ressecções foi verificado através de exames de imagem pós-operatórios. Foram avaliados um total de 12 pacientes. Destes, 6 eram do sexo masculino e 6 do feminino. RESULTADOS: 7 lesões eram tumorais. A ressecção total foi atingida em 66 por cento e ressecção subtotal nos remanescentes. Apenas 1 paciente apresentou déficit motor permanente no pós-operatório e todos os pacientes com quadro prévio de epilepsia refratária obtiveram bom controle das crises no pós-operatório. Em nenhum caso houve necessidade de conversão da anestesia para geral. CONCLUSÃO: O mapeamento funcional intraoperatório na craniotomia com o paciente acordado otimiza a extensão da ressecção da lesão minimizando morbidade permanente. Esta é uma técnica eficaz no manejo de lesões em íntimo contato com o córtex eloqüente, que outrora, seriam designadas inoperáveis.

Neuroprotective effect of grape seed extract against the histopathological changes of the cerebral cortex of adult albino rats induced by aluminum chloride

Aluminum [Al.] is a neurotoxic metal and its exposure may be a factor in the etiology of various neurodegenerative diseases. Recently, a great awareness about the role of Al. in Alzheimer's disease [AD], which demonstrated increasing prevalence of AD in areas with relatively high content of Al. in drinking water. This experimental study tried to identify the histopathological changes induced by aluminum chloride and the possible protective role of grape seed extract against its neurotoxicity using histological and immuno-histochemical study. Material and In this study, 35 adult albino rats were used. The rats were divided into two main groups; control and experimental groups. 9 rats were used as a control group [group I]. The experimental group [group II]; consisted of 26 rats, which were equally subdivided into 2 subgroups; Subgroup [IIa]; each animal received aluminum chloride 100mg/kg.b.wt/day orally for 9 weeks and Subgroup [IIb]; each animal received the same dose of aluminum chloride with concomitant administration of 50mg/kg.b.wt./day grape seed extract orally for 9 weeks. Specimens of the cerebral cortex of the control and experimental groups were taken and prepared for histological and immuno-histochemical examinations. The differently stained sections of the subgroup [IIa] revealed that aluminum chloride induced obvious neuronal damage, where the cortical layers appeared disorganized. The most characteristic pathological feature was the necrosis of the pyramidal cells and appearance of neurofibrillary tangles in their cytoplasm with disappearance of the glutathione reductase enzyme from the cytoplasm of the damaged neurons. The neuropil appeared edematous with dilated blood capillaries containing amyloid collection. On the other hand, addition of grape seed extract in subgroup [IIb] alleviates the deleterious effects of aluminum chloride, where the cortical layers appeared organized with apparently normal blood capillaries. Many pyramidal cells appeared normal with central nuclei and basophilic cytoplasm. However, the neuropil appeared edematous. The immuno-histochemical stain showed reappearance of the+ve reaction to the glutathione reductase enzyme. This experimental study tried to hypothesize that aluminum chloride administration induces histopathological changes, which might be involved in the pathogenesis of AD. It also identified the protective role of grape seed extract against the Al induced neurotoxicity

As bases neuroanatômicas do comportamento: histórico e contribuições recentes / Neuroanatomical basis of behavior: history and recent contributions

Tendo em vista as mais recentes contribuições, as áreas corticais límbicas - originalmente denominadas em conjunto de grande lobo límbico -, além dos giros do cíngulo e parahipocampal, são constituídas pelas regiões mais posteriores do córtex fronto-orbitário e pelo córtex insular. Em contraposição ao restante do córtex cerebral, que se projeta sobre os gânglios da base (particularmente sobre as porções mais dorsais e mais extensas do striatum, constituídas fundamentalmente pelo núcleo caudado e pelo putame), as áreas corticais límbicas se caracterizam por se projetarem principalmente sobre o hipotálamo e também sobre a porção mais ventral do striatum (principalmente sobre o núcleo accumbens). Uma vez que todo o striatum se projeta para o globo pálido - e este para o tálamo, que se projeta para o córtex cerebral, constituindo-se, assim, circuitos córtico-subcorticais reentrantes -, tem-se que, enquanto as alças relacionadas com o striatum e o pallidum dorsais são responsáveis por atividades e rotinas motoras, as alças relacionadas com o striatum e o pallidum ventrais caracterizam circuitos córtico-subcorticais reentrantes e segregados que se relacionam particularmente com funções comportamentais. A amígdala estendida (amígdala centromedial, componente dorsal ou estria terminal, componente ventral e núcleo da estria terminal), por sua vez, também recebe aferências de todas as áreas corticais límbicas, é particularmente modulada pelas áreas corticais pré-frontais e, ao invés de se projetar sobre o striatum, projeta-se diretamente sobre o hipotálamo e o tronco encefálico. Ao receber também conexões diretas do tálamo, a amígdala estendida pode ainda desencadear respostas principalmente autonômicas, de forma inespecífica, porém rápida, através da ativação de centros do tronco encefálico. Os sistemas macro-anatômicos fronto-basais, estriatal-palidal ventral e amígdala estendida, em conjunto com o núcleo basal de Meynert e com o sistema septo-banda...

Considering the most recent contributions, the limbic cortical areas, originally known as the greater limbic lobe, besides the cingulated and the parahippocampal gyri also includes the insula and the posterior orbital cortex. In contrast to the nonlimbic cortical areas that project to the basal ganglia (particularly over the dorsal aspects of the striatum, constituted by the caudate nucleus and by the putamen), the limbic cortical areas are characterized by projecting to the hypothalamus and also to the ventral striatum (particularly to the nucleus accumbens). Once all the striatum projects to the globus pallidus which projects to the thalamus and then to the cortex, generating cortical-subcortical reentrant circuits, while the dorsal striatum and pallidum related cortico-subcortical loops are involved with motor activities, the ventral cortical-striatal-pallidal system is particularly related with behavior functions. The extended amygdala (central medial amygdala, stria terminalis or dorsal component, ventral component, and bed nucleus of stria terminalis) receives inputs primarily from the limbic cortical areas, is particularly modulated by the prefrontal cortex, and receives also direct connections from the thalamus that enables the amygdala to generate nonspecific and quick responses through its projections to the hypothalamus and to the brainstem. The ventral striatal-pallidal and the extended amygdala are then two basal forebrain macro-anatomical systems, that together with the basal nucleus of Meynert and with the septal-diagonal band system, constitute the main structures that are particularly connected with the limbic cortical areas, and that altogether project to the hypothalamus and to the brainstem which give rise to the autonomic, endocrine and somatosensory components of the emotional experiences, and that regulate the basic activities of drinking, eating, and related to the sexual behavior.

A ínsula e o conceito de bloco cerebral central / The insula and the central core concept

A caracterização anatômica de regiões encefálicas topograficamente bem definidas é particularmente útil para a prática neurocirúrgica por propiciar melhor compreensão da tridimensionalidade das suas estruturas e das lesões que as acometem, e por incitar uma maior sistematização dos seus acessos cirúrgicos. Neste sentido, se destaca no interior de cada hemisfério cerebral, um verdadeiro bloco único composto externamente pela ínsula, internamente pelos núcleos da base e tálamo, e que abriga no seu interior a cápsula interna. Com uma conformação predominantemente biconvexa e disposto entre a cisterna silviana e as cavidades ventriculares supratentoriais, esse bloco cerebral central morfologicamente se caracteriza como uma cabeça de cada metade do tronco encefálico, encoberta por todo o manto neocortical do seu hemisfério ao qual se une através de verdadeiros istmos constituídos pelos prolongamentos das diferentes partes da cápsula interna. Anteriormente e sob o sulco limitante anterior da ínsula se dispõem as fibras que compõem o ramo anterior da cápsula interna, superiormente e sob o seu sulco limitante superior se dispõem as fibras restantes do ramo anterior e as do joelho e do ramo posterior, entre as quais se destacam em importância funcional as fibras piramidais córtico-espinhais, e sob o sulco limitante inferior da ínsula se dispõem as partes retro e sub-lentiformes da cápsula interna, que englobam as radiações auditiva e visual. Lateralmente o bloco cerebral central tem a ínsula como um verdadeiro escudo externo das principais estruturas cerebrais subcorticais. As escolhas dos acessos microneurocirúrgicos às lesões relacionadas com o bloco cerebral central devem ter como maior preocupação as suas relações topográficas com o tálamo e com as fibras da cápsula interna.

The caracterization of well defined and circumscribed brain regions is particularly useful for the neurosurgical practice once it enhances the tridimensional understanding of its structures and related lesions, and because it induces the development and the utilization of more standard microneurosurgical approaches. In this direction, it is noteworthy that each cerebral hemisphere harbors an evident central core constituted externally by the insula, internally by the basal ganglia and the thalamus, and with the internal capsule within. With a biconvex configuration when seen from above, and located between the sylvian cistern and the supratentorial ventricular cavities, morphologically this central core resembles a head of each brainstem half top, covered by the neocortical mantle of its hemisphere. The central core is attached to the rest of the cerebral hemisphere by isthmi constituted by the different internal capsule fibers. Anteriorly and under the anterior limiting sulcus of the insula there are fibers of the internal capsule anterior limb, superiorly and under the superior limiting sulcus there are the rest of the anterior limb fibers, and the knee and posterior limb fibers that harbors the corticonuclear and the corticospinal tracts, and inferiorly and under the insular inferior limiting sulcus there are the sub- and the retrolentiform internal capsule fibers that enclose the auditory and the optic radiations. Laterally the central core is composed by the insular surface that resembles a shield of the main cerebral subcortical structures. The options of microneurosurgical approaches to the central core related lesions should consider particularly their relationships with the thalamus and with the internal capsule fibers.