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Si consideramos todos los métodos empleados para analizar la función cerebral desde la electrofisiología hasta las imágenes de resonancia magnética funcional (fMRI), realmente aún siguen siendo técnicas que no satisfacen las necesidades para estudiar el cerebro. Y es esta insatisfacción lo que conlleva a la búsqueda por parte de los investigadores considerar que el conocimiento actual de la funcionalidad cerebral se ha desarrollado y expandido lo suficiente como para ser utilizada en muchos campos, que en esta revisión intentaremos expandir. Desde y aplicabilidad que tiene la fMRI en los trastornos por déficit de atención/hiperactividad (TDAH), trastorno del espectro autista (TEA), trastorno obsesivo-compulsivo (TOC), depresión, epilepsia, neurocirugía, lumbalgia crónica, evento cerebro vascular (ECV), esclerosis múltiple hasta la utilidad que significa para el desarrollo de nuevos fármacos.

El cerebro humano ha sido descrito como un sistema complejo. Su estudio por medio de señales neurofisiológicas ha desvelado la presencia de interacciones lineales y no lineales. En este contexto, se han utilizado métricas de entropía para descubrir el comportamiento cerebral en presencia y ausencia de alteraciones neurológicas. El mapeo de la entropía es de gran interés para el estudio de enfermedades neurodegenerativas progresivas como la enfermedad de Alzheimer. El objetivo de este estudio fue caracterizar la dinámica de las oscilaciones cerebrales en dicha enfermedad por medio de la entropía y la amplitud de las oscilaciones de baja frecuencia a partir de señales Bold de la red por defecto y la red de control ejecutivo en pacientes con Alzheimer e individuos sanos, utilizando una base de datos extraída de la serie de estudios de imágenes de acceso abierto. Los resultados revelaron mayor poder discriminatorio de la entropía por permutaciones en comparación a la amplitud de fluctuación de baja frecuencia y la amplitud fraccional de fluctuaciones de baja frecuencia. Se obtuvo un incremento de la entropía por permutaciones en regiones de la red por defecto y la red de control ejecutivo en pacientes. La corteza cingulada posterior y la precuña manifestaron característica diferencial al evaluar la entropía por permutaciones en ambos grupos. No hubo hallazgos al correlacionar las métricas con las escalas clínicas. Los resultados demostraron que la entropía por permutaciones permite caracterizar la función cerebral en pacientes con Alzheimer, además revela información sobre las interacciones no lineales complementaria a las características obtenidas por medio del cálculo de la amplitud de las oscilaciones de baja frecuencia.

La hipertensión arterial pulmonar es una enfermedad grave que requiere procesos estructurados de diagnóstico con el objetivo de realizar una categorización clínica adecuada con la intención de seleccionar la mejor estrategia terapéutica inicial fundamentada en el riesgo individualizado. Esta estrategia individualizada no tiene sentido si no se tienen metas terapéuticas claras, que no son más que objetivos de tratamiento que permiten guiar las intervenciones buscando que éstas se lleven a cabo de manera temprana y se definan con claridad los momentos de ejecutar escaladas terapéuticas antes de que el paciente se deteriore, con la finalidad de reducir el detrimento funcional y prolongar la vida. Es importante afianzar el mensaje a los clínicos, que una vez iniciado el tratamiento es una obligación vital continuar un seguimiento estratégico y ambicioso para alcanzar la mayor mejoría posible.

Objetivo: Describir los efectos de la restricción moderada del sueño en las regiones cerebrales involucradas en los procesos de inhibición cognitiva, función motora y fluidez fonológica, utilizando imágenes por resonancia magnética funcional (RMf). Materiales y métodos: Se estableció una condición de sueño habitual y otra de restricción moderada en 12 estudiantes diestros de pre y posgrado de Medicina, de entre 20 y 40 años. En ambos estados se utilizó la prueba psicológica de atención d2 e imágenes de RMf con paradigmas de función motora, fluencia fonológica y atención del tipo inhibición de la función ejecutiva Stroop. La restricción moderada de sueño fue de al menos el 63% con respecto al sueño habitual. Resultados: Se encontraron diferencias significativas en la activación cerebral con RMf para la función motora (p

BACKGROUND: Despite rapid developments in fMRI, there is still ongoing debate on the optimal paradigm for evaluating the level of auditory cortex activation. MATERIAL AND METHODS: A number of modern neuroimaging methods can be used to assess brain responses to acoustic stimulation, but new paradigms are still needed. Here the sparse fMRI approach is used to examine frequency-specific activation in auditory cortex in 12 normal hearing individuals. RESULTS: The size of activation expanded with increasing sound intensity and decreasing sound frequency. At the same time, the main site of frequency-specific activation remained the same across intensities, indicating fixed tonotopic organization. The findings of the study are explained in terms of basilar membrane phenomena such as the travelling wave pattern and spread of activation. CONCLUSIONS: Stimulation levels of at least 60 dB are necessary in order to obtain robust maps of group activation in auditory cortex. [ABSTRACT FROM AUTHOR]

La epilepsia es una alteración neurológica crónica caracterizada por crisis recurrentes. Se estima que aproximadamente el 30% de los pacientes con crisis epilépticas focales son refractarios al tratamiento médico. Las causas más comunes de epilepsia encontradas en estos pacientes corresponden a Esclerosis Temporal Mesial (ETM), Malformaciones del Desarrollo Cortical (MDC), tumores, lesiones vasculares y lesiones secuelares. Los pilares para el diagnóstico de las epilepsias refractarias son las manifestaciones clínicas, las alteraciones electroencefalográficas y las imágenes de Resonancia Magnética (RM). El rol de las imágenes en la evaluación de estos pacientes es identificar, localizar y delimitar la extensión de la lesión subyacente, así como tratar de determinar su etiología. Se ha estimado que sólo es posible determinar la existencia de una lesión estructural subyacente en el 82-86% de los pacientes con epilepsia focal, incluso utilizando protocolos para el estudio de epilepsia. Por lo tanto existe un grupo de pacientes con epilepsia focal refractaria al tratamiento médico que tienen RM normales, lo que se ha relacionado con un peor pronóstico post quirúrgico. Por esto se requiere de nuevos recursos para la identificación de alteraciones subyacentes en este grupo de pacientes, quienes frecuentemente tienen displasias corticales, ETM o lesiones secuelares pequeñas. Necesitamos nuevas técnicas para aumentar la visualización de las lesiones, como la búsqueda de signos radiológicos clásicos con software de post proceso, mediante la localización de las áreas de pérdida de diferenciación de la unión córticosubcortical y aumento del espesor cortical. Las imágenes cuantitativas T2 permiten determinar características específicas e invariables de los tejidos, que ayudan a la detección de alteraciones sutiles de la intensidad de señal. La volumetría se utiliza especialmente para la determinación cuantitativa de volúmenes hipocampales, en los casos de lesiones unilaterales leves o lesiones bilaterales que son difíciles de evaluar visualmente. Las imágenes de RM funcional permiten la localización de las áreas elocuentes, especialmente para funciones motoras, visuales y de lenguaje. Las imágenes con Tensor de Difusión hacen posible le visualización de los tractos y su relación con las lesiones epileptogénicas. Las imágenes durante la cirugía permiten la integración de toda la información, que puede ser de ayuda para la determinación de los límites de la resección y localización de las áreas elocuentes. La ecografía intraoperatoria muchas veces es muy útil para determinar la extensión de las lesiones.

En este artículo discutimos investigaciones recientes relacionadas a los mecanismos neurobiológicos subyacentes al Trastorno por Déficit Atencional e Hiperactividad, (TDAH) en particular la dinámica de señalización dopaminérgica y la llamada red por defecto, que consiste en patrones de actividad que se generan durante el reposo. Ambos tipos de fenómenos han sido asociados al TDAH y aquí proponemos una relación entre ambas dinámicas, y cómo ésta puede estar afectada en el TDAH.

Social cognition impairments are frequently found in patients with mild traumatic brain injury (TBI) when structural lesions may not reveal the severity of the injury. Though instruments used to assess social behavior are thought to be sensitive, the absence of structural damage in TBI patients may lead to underscore such problems. The aim of this study was to develop a complementary diagnostic tool such as a paradigm for functional Magnetic resonance Imaging (fMRI) involving a simple task that could tell how patients understand certain complex social behavior by identifying different movements with or without social intentions where language and complex cognitive process were not required. Eleven patients with mild TBI and social cognition difficulties and twelve control subjects were matched by demographic variables. A paradigm of social fMRI was developed by using dots in movement representing human motion, human motion with social intention such as dancing or sharing, and dots moving without meaning. Patients had less activation in parietotemporal junction and bilateral middle frontal gyrus in the social perception task movement compared with control group subjects. The fMRI paradigm developed can be an additional diagnostic tool for identifying social cognition impairments in mild TBI patients. Regardless the absence of structural injury, changes in activation areas suggest a prospective use of this tool since clinical, cognitive and functional outcomes support such finding. [ABSTRACT FROM AUTHOR]

Family-focused therapy ( FFT) is an evidence-based intervention for adults and children with bipolar disorder ( BD) and their caregivers, usually given in conjunction with pharmacotherapy after an illness episode. The treatment consists of conjoint sessions of psychoeducation regarding bipolar illness, communication enhancement training, and problem-solving skills training. This paper summarizes over 30 years of research on FFT and family processes in BD. Across eight randomized controlled trials with adults and adolescents with BD, FFT and mood-stabilizing medications have been found to hasten recovery from mood episodes, reduce recurrences, and reduce levels of symptom severity compared to briefer forms of psychoeducation and medications over 1-2 years. Several studies indicate that the effects of FFT on symptom improvement are greater among patients with high-expressed emotion relatives. New research focuses on FFT as an early intervention for youth at risk for BD, neuroimaging as a means of evaluating treatment mechanisms, and progress in implementing FFT in community mental health settings. [ABSTRACT FROM AUTHOR]

Introducción: la enfermedad de Alzheimer es una enfermedad neurodegenerativa y la causa de demencia más frecuente en el mundo. Esta enfermedad se caracteriza por muerte neuronal que lleva a una pérdida de conectividad cerebral general. Técnicas como la conectividad funcional a partir de imágenes de resonancia magnética pueden brindar información acerca de la interacción entre regiones cerebrales y, por tanto, puede ser un indicador del Alzheimer. Objetivo: evaluar la conectividad funcional a partir de imágenes de resonancia magnética funcional en estado de reposo en adultos mayores como posible biomarcador para la enfermedad de Alzheimer. Materiales y métodos: en una población de 35 sujetos de edad avanzada (10 pacientes con Alzheimer de 75 ± 2,87 años, 10 pacientes con deterioro cognitivo leve de 74,9 ± 2,88 años, y 15 personas sanas de 75,35 ± 2,91 años), se compararon las redes de conectividad funcional obtenidas a través de la correlación temporal de la señal BOLD y elementos de la teoría de grafos. Se calcularon las medidas de las redes (costo y grado medio), y se correlacionaron estas medidas con las escalas neuropsicológicas ADNI-mem y ADAS-Cog. Resultados: en los pacientes con Alzheimer hay una disminución de la conectividad en comparación con los controles sanos y los pacientes con deterioro cognitivo leve. Se encontró una correlación significativa entre el costo de las redes en los sujetos sanos y las escalas neuropsicológicas. Conclusión: se confirma la desconexión existente en la enfermedad de Alzheimer y se muestra que la alteración de la actividad cerebral en el deterioro cognitivo y Alzheimer se puede medir mediante el algoritmo basado en grafos desarrollado en este trabajo.

Background: Recently, there has been a surge of interest in neuroimaging techniques that might help to objectively evaluate the residual hearing abilities of patients with hearing abilities of patients considered for partial deafness treatment (PDT). Such an evaluation might allow a wider range of PD candidates to benefit from cochlear implantation (CI). Although existing studies suggest that functional magnetic resonance (fMRI) may help predict the benefits of CI for hearing-impaired patients, little is known about the activity of the primary auditory cortex in patients with partial deafness. This study is the first to apply fMRI to examine BOLD signal changes in the auditory cortex induced by chirp stimulation in patients with partial deafness. Material and Method: Ten patients considered for partial deafness treatment with electro-acoustic stimulation (PDT-EAS) and 10 patients considered for electrical complement treatment (PDT-EC) according to Skarźyński's categorization of partial deafness treatment (PDT) participated in the study. fMRI measurements were performed in a 3T Siemens Magnetom Trio scanner at the Bioimaging Research Center (BRC) of the Institute of Physiology and Pathology of Hearing in Kajetany, Poland. During the fMRI study, subjects were presented with a chirp of two different bandwidths: 50-950 Hz (middle frequency 500 Hz) and 3000-5000 Hz (middle frequency 4000 Hz) at 90 dB(C) via MRI-compatible earphones. A sparse paradigm was used and the data was analyzed using the SPM8 package (Statistical Parametric Mapping, http://www.fil.ion.ucl.ac.uk/spm/). Standard preprocessing was followed by a second-level analysis for contrast of low and high frequencies. Results: As expected, bilateral activation in the auditory cortex was observed in response to stimulation by 500 Hz chirps in PDT-EAS and PDT-EC candidates. Activation in response to 4000 Hz chirps were found only in the PDT-EAS group but less strongly than for 500 Hz chirps. Conclusions: fMRI can be used as an objective way of assessing residual hearing in the auditory cortex of patients with partial deafness. [ABSTRACT FROM AUTHOR]

Introduction: The neural correlates of the cognitive dysfunction in first-episode psychosis (FEP) are still unclear. The present review and meta-analysis provide an update of the location of the abnormalities in the fMRI-measured brain response to cognitive processes in individuals with FEP., Methods: Systematic review and voxel-based meta-analysis of cross-sectional fMRI studies comparing neural responses to cognitive tasks between individuals with FEP and healthy controls (HC) according to PRISMA guidelines., Results: Twenty-six studies were included, comprising 598 individuals with FEP and 567 HC. Individual studies reported statistically significant hypoactivation in the dorsolateral prefrontal cortex (6 studies), frontal lobe (8 studies), cingulate (6 studies) and insula (5 studies). The meta-analysis showed statistically significant hypoactivation in the left anterior insula, precuneus and bilateral striatum., Conclusions: While the studies tend to highlight frontal hypoactivation during cognitive tasks in FEP, our meta-analytic results show that the left precuneus and insula primarily display aberrant activation in FEP that may be associated with salience attribution to external stimuli and related to deficits in perception and regulation., (Copyright © 2020 SEP y SEPB. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction: The neural correlates of the cognitive dysfunction in first-episode psychosis (FEP) are still unclear. The present review and meta-analysis provide an update of the location of the abnormalities in the fMRI-measured brain response to cognitive processes in individuals with FEP., Methods: Systematic review and voxel-based meta-analysis of cross-sectional fMRI studies comparing neural responses to cognitive tasks between individuals with FEP and healthy controls (HC) according to PRISMA guidelines., Results: Twenty-six studies were included, comprising 598 individuals with FEP and 567 HC. Individual studies reported statistically significant hypoactivation in the dorsolateral prefrontal cortex (6 studies), frontal lobe (8 studies), cingulate (6 studies) and insula (5 studies). The meta-analysis showed statistically significant hypoactivation in the left anterior insula, precuneus and bilateral striatum., Conclusions: While the studies tend to highlight frontal hypoactivation during cognitive tasks in FEP, our meta-analytic results show that the left precuneus and insula primarily display aberrant activation in FEP that may be associated with salience attribution to external stimuli and related to deficits in perception and regulation., (Copyright © 2020 SEP y SEPB. Publicado por Elsevier España, S.L.U. All rights reserved.)

Introduction: Dysembryoplastic neuroepithelial tumours (DNET) are a type of benign glioneuronal neoplasia of typically temporal location that produce drug-resistant epileptic seizures in children and young adults., Objective: This work aims to assess the usefulness of functional magnetic resonance imaging (fMRI) in the preoperative study in four patients with DNET. A Philips Intera 3.0 Tesla magnetic resonance imaging scanner and the Blood-Oxygen-Level-Dependent (BOLD) technique were used to obtain the images, making it possible to locate the eloquent areas for language and motor areas through the application of specific paradigms., Results: In one case the tumour was adjacent to Broca's area, in two cases it coincided with Wernicke's area, in one patient it was<1cm from the motor area for the hand and in another close to memory. Only two of the patients were operated on, without postoperative functional deficit. Hemispheric activation contralateral to the tumour suggestive of neuroplasticity was observed in one of the patients., Conclusions: fMRI is a non-invasive method that allows us to assess the proximity of lesions to eloquent areas, which is key in the evaluation of surgical risk. In addition, it allowed the detection of probable neuroplasticity in one case, which guaranteed the success of the surgery., (Copyright © 2019 Sociedad Española de Neurocirugía. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objectives: To describe the normal patterns of cerebellar activation in specific cerebral functions (motor, language, memory) and their topographical correlations in the cerebellar cortex on functional magnetic resonance imaging., Materials and Methods: We evaluated 25 healthy subjects (8 women and 17 men; 23 right-handed and 2 left-handed; age range, 16-64 years), who did language, memory, and motor tasks while undergoing 1.5T functional magnetic resonance imaging., Results: We assessed functional activity of the cerebellum associated with motor, language, and memory components, describing their relations with topographical regions of the cerebellum and their functional relations with areas in the cerebral cortex., Conclusions: Knowledge of the normal patterns of morphological characteristics and functional behavior in the cerebellum as well as their relations with the brain is important for radiologists and clinicians evaluating the cerebellum and possible pathological conditions that affect it., (Copyright © 2020 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objective: To explore whether children and adolescents with attention deficit/hyperactivity disorder (ADHD) have altered the functional connectivity between the executive control network and the default mode network., Methods: Exploratory study of a diagnostic test, prospective, case and control design. A total of 56 participants were recruited consecutively (29 inattentive or combined ADHD subtype and 27 controls) between 7 and 16 years old, male, right dominance. DSM-5 was applied as reference test and a battery of neuropsychological tests to confirm the diagnosis and assess comorbidities. Resting state functional magnetic resonance imaging was performed as an index test. The application and evaluation of the tests was blind. The brain regions were chosen a priori and the region of interest technique was used. The functional connectivity of the anterior cingulate cortex (ACC) was evaluated with: the precuneus (P), the posterior cingulate cortex (PCC) and the dorsomedial prefrontal cortex (DMPC)., Results: The functional connectivity in each of the associations evaluated in the patients with ADHD compared with the controls were: P&#95;D=0.41 vs 0.44; CCP&#95;D=0.43 vs 0.53; CPDM&#95;D=0.75 vs. 0.79; P&#95;I=0.40 vs 0.41; CCP&#95;I=0.48 vs 0.53; CPDM&#95;I=0.76 vs. 0.72). D: right side I: left side. Value of p> 0.05., Conclusion: Cerebral functional connectivity at rest is lower in ADHD patients when compared with healthy controls, however, the difference was not statistically significant., (Copyright © 2019 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.)

Introduction: Given that surgical treatment of refractory mesial temporal lobe epilepsy may cause memory impairment, determining which patients are eligible for surgery is essential. However, there is little agreement on which presurgical memory assessment methods are best able to predict memory outcome after surgery and identify those patients with a greater risk of surgery-induced memory decline., Objective: We conducted a systematic literature review to determine which presurgical memory assessment methods best predict memory outcome., Material and Methods: The literature search of PubMed gathered articles published between January 2005 and December 2015 addressing pre- and postsurgical memory assessment in mesial temporal lobe epilepsy patients by means of neuropsychological testing, functional MRI, and other neuroimaging techniques. We obtained 178 articles, 31 of which were included in our review., Results: Most of the studies used neuropsychological tests and fMRI; these methods are considered to have the greatest predictive ability for memory impairment. Other less frequently used techniques included the Wada test and FDG-PET., Conclusions: Current evidence supports performing a presurgical assessment of memory function using both neuropsychological tests and functional MRI to predict memory outcome after surgery., (Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Functional magnetic resonance imaging (fMRI) is an advanced tool for the study of brain functions in healthy subjects and in neuropsychiatric patients. This tool makes it possible to identify and locate specific phenomena related to neuronal metabolism and activity. Starting with the detection of changes in the blood supply to a region that participates in a function, more complex approaches have been developed to study the dynamics of neuronal networks. Studies examining the brain at rest or involved in different tasks have provided evidence related to the onset, development, and/or response to treatment in various diseases. The diversity of the possible artifacts associated with image registration as well as the complexity of the analytical experimental designs has generated abundant debate about the technique behind fMRI. This article aims to introduce readers to the fundamentals underlying fMRI, to explain how fMRI studies are interpreted, and to discuss fMRI's contributions to the study of the mechanisms underlying diverse diseases of the nervous system., (Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.)

Aphasia is an acquired language disorder due to a cerebral lesion; it is characterized by errors in production, denomination, or comprehension of language. Although most aphasias are mixed, from a practical point of view they are classified into different types according to their main clinical features: Broca's aphasia, Wernicke's aphasia, conduction aphasia, transcortical aphasia, and alexia with or without agraphia. We present the clinical findings for the main subtypes of aphasia, illustrating them with imaging cases, and we provide an up-to-date review of the language network with images from functional magnetic resonance imaging and tractography., (Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.)

Introduction: Knee osteoarthritis is causing pain and functional disability. One of the inherent problems with efficacy assessment of pain medication was the lack of objective pain measurements, but functional magnetic resonance imaging (fMRI) has emerged as a useful means to objectify brain response to painful stimulation. We have investigated the effect of chondroitin sulfate (CS) on brain response to knee painful stimulation in patients with knee osteoarthritis using fMRI., Methods: Twenty-two patients received CS (800mg/day) and 27 patients placebo, and were assessed at baseline and after 4 months of treatment. Two fMRI tests were conducted in each session by applying painful pressure on the knee interline and on the patella surface. The outcome measurement was attenuation of the response evoked by knee painful stimulation in the brain., Results: fMRI of patella pain showed significantly greater activation reduction under CS compared with placebo in the region of the mesencephalic periaquecductal gray. The CS group, additionally showed pre/post-treatment activation reduction in the cortical representation of the leg. No effects of CS were detected using the interline pressure test., Conclusions: fMRI was sensitive to objectify CS effects on brain response to painful pressure on patellofemoral cartilage, which is consistent with the known CS action on chondrocyte regeneration. The current work yields further support to the utility of fMRI to objectify treatment effects on osteoarthritis pain., (Copyright © 2017 Elsevier España, S.L.U. All rights reserved.)

Objective: To describe the detection of cortical areas and subcortical pathways involved in language observed in MRI activation studies and tractography in a 3T MRI scanner and to correlate the findings of these functional studies with direct intraoperative cortical and subcortical stimulation., Material and Methods: We present a series of 14 patients with focal brain tumors adjacent to eloquent brain areas. All patients underwent neuropsychological evaluation before and after surgery. All patients underwent MRI examination including structural sequences, perfusion imaging, spectroscopy, functional imaging to determine activation of motor and language areas, and 3D tractography. All patients underwent cortical mapping through cortical and subcortical stimulation during the operation to resect the tumor. Postoperative follow-up studies were done 24 hours after surgery., Results: The correlation of motor function and of the corticospinal tract determined by functional MRI and tractography with intraoperative mapping of cortical and subcortical motor areas was complete. The eloquent brain areas of language expression and reception were strongly correlated with intraoperative cortical mapping in all but two cases (a high grade infiltrating glioma and a low grade glioma located in the frontal lobe). 3D tractography identified the arcuate fasciculus, the lateral part of the superior longitudinal fasciculus, the subcallosal fasciculus, the inferior fronto-occipital fasciculus, and the optic radiations, which made it possible to mark the limits of the resection. The correlation with the subcortical mapping of the anatomic arrangement of the fasciculi with respect to the lesions was complete., Conclusion: The best treatment for brain tumors is maximum resection without associated deficits, so high quality functional studies are necessary for preoperative planning., (Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.)