ABSTRACT
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.
ABSTRACT
Background music has been increasingly affecting people's lives. The research on the influence of background music on working memory has become a hot topic in brain science. In this paper, an improved electroencephalography (EEG) experiment based on n-back paradigm was designed. Fifteen university students without musical training were randomly selected to participate in the experiment, and their behavioral data and the EEG data were collected synchronously in order to explore the influence of different types of background music on spatial positioning cognition working memory. The exact low-resolution brain tomography algorithm (eLORETA) was applied to localize the EEG sources and the cross-correlation method was used to construct the cortical brain function networks based on the EEG source signals. Then the characteristics of the networks under different conditions were analyzed and compared to study the effects of background music on people's working memory. The results showed that the difference of peak periods after stimulated by different types of background music were mainly distributed in the signals of occipital lobe and temporal lobe ( < 0.05). The analysis results showed that the brain connectivity under the condition with background music were stronger than those under the condition without music. The connectivities in the right occipital and temporal lobes under the condition of rock music were significantly higher than those under the condition of classical music. The node degrees, the betweenness centrality and the clustering coefficients under the condition without music were lower than those under the condition with background music. The node degrees and clustering coefficients under the condition of classical music were lower than those under the condition of rock music. It indicates that music stimulation increases the brain activity and has an impact on the working memory, and the effect of rock music is more remarkable than that of classical music. The behavioral data showed that the response accuracy in the state of no music, classical music and rock music were 86.09% ± 0.090%, 80.96% ± 0.960% and 79.36% ± 0.360%, respectively. We conclude that background music has a negative impact on the working memory, for it takes up the cognitive resources and reduces the cognitive ability of spatial location.
Subject(s)
Humans , Brain , Cognition , Electroencephalography , Memory, Short-Term , MusicABSTRACT
Exposure to normobaric hyperoxia (NH) is known to increase the production of reactive oxygen species (ROS) by mitochondria. The present study was designed to examine mitochondrial ultrastructure morphological changes in the cortical brainin relation to glutathione peroxidase (GPX) activity and free radicals (FR) productions in brain tissue during hyperoxia exposure. The experimental groups were exposed to NH for 24 and 48 h continuously. Following the exposure periods, animals were sacrificed and cortical tissues were divided randomly into two parts; the first part was processed for the ultrastructural examination and the second was homogenized for GPX and FR determinations. Analysis of variance (ANOVA) showed that the main effects of O2 exposure periods were significant (p<0.05) for GPX and FR. Pair-wise means comparisons showed that NH elevated the average (+SE) GPX activity significantly (p<0.05) from the baseline control value of 5670.99+556.34 to13748.42+283.04 and 15134.19+1529.26 U/L with increasing length of NH exposure period from 24 to 48 h, respectively. Similarly, FR production was increased significantly (p<0.05) to 169.73+10.31 and 185.33+21.87, above baseline control of 105.27+5.25 Unit. Ultrastructure examination showed that O2 breathing for 48 h resulted in giant and swelled mitochondria associated with diluted inner membrane and damaged cristae. These mitochondria pathological alterations were associated with damages of myelin, axonal and cellular organelles. Normobaric-hyperoxia inducts mitochondria oxidative stress (MOS) and the subsequent rise of ROS causes variety of ultrastructure morphological pathological alterations in the organelles of cortical brain cells.
Se sabe que la exposición a la hiperoxia normobárica (HN) aumenta la producción de especies reactivas de oxígeno (ERO) por parte de las mitocondrias. El estudio se diseñó para examinar los cambios morfológicos de la ultraestructura mitocondrial en la corteza cerebral con la actividad de la glutatión peroxidasa (GPX) y la producción de radicales libres (RL) en el tejido cerebral durante la exposición a la hiperoxia. Los grupos experimentales fueron expuestos a HN durante 24 y 48 h continuamente. Tras los períodos de exposición, los animales se sacrificaron y los tejidos corticales se dividieron aleatoriamente en dos partes; la primera parte se procesó para el examen ultraestructural y la segunda se homogeneizó para las determinaciones de GPX y RL. El análisis de varianza (ANOVA) mostró que los efectos principales de los períodos de exposición al O2 fueron significativos (p <0,05) para GPX y RL. Las comparaciones de medias por pares mostraron que la HN elevó la actividad promedio de GPX (+ SE) significativamente (p <0,05) desde el valor de control de línea base de 5670,99 + 556,34 a 13748,42 + 283,04 y 15134,19 + 1529,26 U / L con una mayor duración del período de exposición a HN de 24 a 48 h, respectivamente. De manera similar, la producción de RL se incrementó significativamente (p <0,05) a 169,73 + 10,31 y 185,33 + 21,87, por encima del control de referencia de 105,27 + 5,25 unidades. El examen de la ultraestructura mostró que la respiración de O2 durante 48 h dio lugar a mitocondrias gigantes e hinchadas asociadas con la membrana interna diluida y las crestas dañadas. Estas alteraciones patológicas de las mitocondrias se asociaron con daños de mielina, axones y organelos celulares. La hiperoxia normobárica induce el estrés oxidativo mitocondrial (MOS) y el posterior aumento de las ERO provoca una variedad de alteraciones patológicas y morfológicas en los organelos de las células cerebrales corticales.