Técnicas de Neuroimagenología en la Cuantificación de la Neuroplasticidad en Pacientes con Enfermedad Vascular Cerebral / Neuroimaging Techniques for Neuroplasticity Quantification in Stroke Patients

RESUMEN Las técnicas de neuroimagenología otorgan información relevante del estado funcional y anatómico del cerebro humano. Esta información es particularmente importante cuando existe una lesión cerebral causada por alguna patología, tal como la enfermedad vascular cerebral (EVC). En pacientes afectados por esta enfermedad, se ha determinado que la neuroplasticidad es el mecanismo principal de recuperación de la función motora perdida. Debido a la alta prevalencia de la EVC a nivel mundial y especialmente en países en vías de desarrollo, es necesario continuar investigando los mecanismos de recuperación involucrados en esta patología. La resonancia magnética funcional (RMF) y la imagenología por tensor de difusión (ITD) son dos de las técnicas de neuroimagenología más utilizadas con este fin. La RMF permite analizar la actividad neuronal generada al ejecutar tareas de movimiento, mientras que la ITD proporciona información estructural de la anatomía cerebral. En esta revisión narrativa, se presentan diversos estudios que han utilizado estas técnicas de neuroimagenología en la cuantificación de los cambios de neuroplasticidad en pacientes con EVC tras participar en algún programa de neurorrehabilitación. Comprender mejor estos cambios de neuroplasticidad permitiría diseñar esquemas de rehabilitación que proporcionen un mayor beneficio a los pacientes con EVC.

ABSTRACT Neuroimaging techniques provide relevant information of the functional and anatomical status of the human brain. This information is of particular importance when a pathology, like stroke, produces a brain injury. In stroke patients, it has been determined that neuroplasticity is the primary recovery mechanism of the lost motor function. Due to worldwide high prevalence, especially in developing countries, it is necessary to continue the research of the recovery mechanisms involved in this pathology. To this end, functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are two of the most used neuroimaging techniques. In stroke patients, fMRI allows the analysis of the neural activity produced by the execution of motor tasks, whereas DTI provides structural information of the brain anatomy. In this narrative review, multiple studies that employ these neuroimaging techniques for quantification of neuroplasticity changes in stroke patients after undergoing a neurorehabilitation program are presented. Better understanding of these neuroplasticity changes would allow researchers to design and provide more beneficial rehabilitation schemes to stroke patients.

Correlación entre estado emocional y activación funcional mediante resonancia magnética / Correlation between emotional state and functional activation with magnetic resonance imaging

Resumen Objetivo: Explorar si voluntarios sanos presentarían correlación entre su puntaje en un test psicológico emocional y las activaciones de áreas cerebrales relacionadas con las emociones medidas con resonancia magnética funcional (RMf). Material y métodos: Estudio exploratorio de prueba diagnóstica, prospectivo, con diseño del propio individuo como control, con muestra de 12 participantes. Se categorizó a cada participante con un puntaje de estabilidad emocional derivado de un test psicológico y se utilizaron estímulos emocionales audiovisuales durante las adquisiciones de RMf. Resultados: La sumatoria de clusters de activación medidos en cantidad total de vóxeles durante los estímulos negativos en áreas cerebrales relacionadas con las emociones mostró una correlación negativa estadísticamente significativa para nuestro tamaño de muestra respecto de los puntajes en el test emocional, con rho de Spearman de −0,623 y p = 0,0428. Conclusiones: Los paradigmas de RMf utilizados permitieron cuantificar las activaciones cerebrales ante estímulos emocionales de valencia positiva y negativa, y los resultados obtenidos abren una perspectiva hacia la posibilidad de utilizar test psicológicos y secuencias de RMf para predecir la posibilidad de aparición de síntomas de patologías psicológicas o psiquiátricas ante factores desencadenantes en población sana que presente en estos test valores cercanos al límite de la normalidad.

Abstract Objective: To explore if healthy volunteers would present a correlation between their score in emotional psychological test and the activations of brain areas related to emotions measured with functional magnetic resonance imaging (fMRI). Material and methods: Exploratory study of a prospective diagnostic test, with the individual’s own design as a control, with a sample of 12 participants. Each participant was categorized with an emotional stability score derived from a psychological test and audiovisual emotional stimuli were used during fMRI acquisitions. Results: The sum of activation clusters measured in total number of voxels during negative stimuli in brain areas related to emotions showed a statistically significant negative correlation for our sample size with respect to the scores in the emotional test, with Spearman’s rho of −0.623 and p = 0.0428. Conclusions: The fMRI paradigms used made it possible to quantify brain activations in response to emotional stimuli of positive and negative valence, and the results obtained open a perspective towards the possibility of using psychological tests and fMRI sequences to predict the possibility of the appearance of symptoms of psychological or psychiatric pathologies in response to triggering factors in a healthy population that present values close to the normal limit in these tests.

Contributions from functional neuroimaging studies to the comprehension of traumatic child experiences: preliminary findings / Aportes de los estudios de neuroimagen funcional a la comprensión del trauma infantil: estudio preliminar

Abstract This study aimed to describe the cerebral activation patterns using fMRI (Functional Magnetic Resonance Imaging) technology in a sample of 15 children with Posttraumatic Stress Disorder (PTSD) and 7 with no PTSD. The study used a Quasi-experimental methodology where two experimental tasks were applied: an emotional face task and a version of an emotional Stroop task. The results point out differences in the group of PTSD on the processing of negative stimuli and changes in their frontal lobe activation. These preliminary results suggest that early traumatic experiences affect typical brain development patterns. And explicit and implicit variables involved in the traumatic experiences are discussed as a part of any intervention process.

Resumen El presente estudio tuvo como objetivo describir patrones de activación cerebral mediante una técnica de Imagen por resonancia magnética funcional -fMRI- (abreviatura en inglés de Functional Magnetic Resonance Imaging) en una muestra de niños con Trastorno de estrés postraumático (TEPT) y compararlos con un grupo de controles. Estudio cuasi-experimental en el que se tomó un grupo de 15 niños con TEPT y se comparó con un grupo de 7 niños sin TEPT. Se emplearon dos tareas experimentales: una prueba de caras y una versión del Stroop emocional. Los resultados preliminares, señalan diferencias en el procesamiento de estímulos, principalmente de carácter negativo en los niños con TEPT y cambios en los patrones de activación a nivel de estructuras frontales. Se concluye que el trauma a edad temprana afecta el curso normal del desarrollo cerebral y se evidencia la importancia de abordar los aspectos explícitos e implícitos asociados a la experiencia traumática como parte de la intervención.

Cerebral Responses to Stationary Emotional Stimuli Measured by fMRI in Women with Persistent Postural-Perceptual Dizziness

Abstract Introduction Persistent postural-perceptual dizziness (PPPD) is a functional vestibular disorder characterized by chronic dizziness, unsteadiness, and hypersensitivity to motion. Preexisting anxiety disorders and neurotic personality traits confer vulnerability to PPPD. High anxiety during acute vertigo or dizziness incites it. A functional magnetic resonance imaging (fMRI) study of chronic subjective dizziness found unexpectedly hypoactive responses to vestibular stimulation in cortical regions that integrate threat assessment and spatial perception. Objective This fMRI study used non-moving, but emotionally charged visual stimuli to investigate the brain's activity of PPPD patients and control subjects. Methods The participants included 16 women with PPPD and 16 age-matched women who recovered completely from acute episodes of vertigo or dizziness capable of triggering PPPD. Brain responses to positive, neutral, and negative figures from the International Affective Picture System were measured with fMRI and compared between the groups. Dizziness handicap, anxiety, and depression were assessed with validated questionnaires. Results Between group analyses: Participants with PPPD showed reduced activity in anterior cingulate cortex and increased activity in left angular gyrus in response to negative versus positive stimuli, which was not observed in recovered individuals. Within group analyses: Participants with PPPD had increased activity in visuospatial areas (parahippocampal gyrus, intraparietal sulcus) in negative versus positive and negative versus neutral contrasts, whereas recovered individuals had increased activity in anxiety regions (amygdala, orbitofrontal cortex). Conclusion Patients with PPPD may be more attuned to spatial elements than to the content of emotionally charged visual stimuli.

Association between poor tolerability of antidepressant treatment and brain functional activation in youth at risk for bipolar disorder

Objective: To investigate whether poor antidepressant tolerability is associated with functional brain changes in children and adolescents of parents with bipolar I disorder (at-risk youth). Methods: Seventy-three at-risk youth (ages 9-20 years old) who participated in a prospective study and had an available baseline functional magnetic resonance imaging (fMRI) scan were included. Research records were reviewed for the incidence of adverse reactions related to antidepressant exposure during follow-up. The sample was divided among at-risk youth without antidepressant exposure (n=21), at-risk youth with antidepressant exposure and no adverse reaction (n=12), at-risk youth with antidepressant-related adverse reaction (n=21), and healthy controls (n=20). The fMRI task was a continuous performance test with emotional distracters. Region-of-interest mean activation in brain areas of the fronto-limbic emotional circuit was compared among groups. Results: Right amygdala activation in response to emotional distracters significantly differed among groups (F3,66 = 3.1, p = 0.03). At-risk youth with an antidepressant-related adverse reaction had the lowest amygdala activation, while at-risk youth without antidepressant exposure had the highest activation (p = 0.004). Conclusions: Decreased right amygdala activation in response to emotional distracters is associated with experiencing an antidepressant-related adverse reaction in at-risk youth. Further studies to determine whether amygdala activation is a useful biomarker for antidepressant-related adverse events are needed.

Explore functional brain changes in bipolar disorder: A whole brain ALE meta-analysis

ABSTRACT Background: Previous functional magnetic resonance imaging (fMRI) studies showed inconsistent results for comparison between bipolar disorder (BD) and healthy controls (HC). Methods: An anatomic likelihood estimation (ALE) meta-analysis was used to explore the key regions of brain pathology in BD with different current mood states. Results: Depressed BD patients showed reduced regional homogeneity (ReHo) in the left claustrum and the left middle frontal gyrus (MFG), compared to HC. BD patients with mixed mood status showed decreased fractional amplitude of low frequency fluctuations (fALFF) in the right cerebellar tonsil, the bilateral MFG and the right superior frontal gyrus, compared to HC. Additionally, BD patients with mixed mood status showed increased fALFF in the right inferior occipital gyrus, the right culmen and the left lentiform nucleus, compared to HC. BD patients with mixed mood status showed decreased functional connectivity (FC) in the bilateral cerebellar tonsil, compared to HC. Conclusion: In the present study, key regions undergoing functional deficits in BD patients with different current mood states were obtained with the ALE meta-analysis. In addition, deficits in these regions in fMRI studies might work as biomarkers for early diagnosis of BD.

Biomarcadores de neuroimagen para el diagnóstico temprano de la enfermedad de Alzheimer: un abordaje desde las redes neuronales / Neuroimaging biomarkers for early diagnosis of Alzheimers Disease: an approach from neural networks

Resumen: Las crecientes cifras mundiales de prevalencia e incidencia de la Enfermedad de Alzheimer exigen el desarrollo de métodos diagnósticos cada vez más precoces. La enfermedad suele diagnosticarse cuando la patología ya está avanzada y poco se puede hacer terapéuticamente, conllevando una gran pérdida de años de vida y altos costos sociales y familiares. Considerando esta patología como una disrupción a gran escala de las redes neuronales del cerebro humano, distintos estudios han propuesto biomarcadores basados en resonancia magnética y tomografía por emisión de positrones. El presente artículo revisa sistemáticamente dichos estudios considerando un abordaje desde la ciencia de redes neuronales.

Abstract: The increased global prevalence and incidence of Alzheimer's Disease demands the development of early diagnostic methods. This disease is usually diagnosed when the pathology is already advanced and therapeutically, there's not much to do, leading to a great loss of years of life, high socials and family costs. Considering this pathology as a large-scale disruption of neural networks of the human brain, different studies have proposed biomarkers based on functional magnetic resonance imaging and positron emission tomography. This article systematically reviews these studies considering an approach of neural networks science.

Regularized Hypothesis Testing in Random Fields with Applications to Neuroimaging / Pruebas de Hipótesis Regularizadas en Campos Aleatorios con Aplicaciones a Neuroimágenes

Abstract The task of determining for which elements of a random field (e.g., pixels in an image) a certain null hypothesis may be rejected is a relevant problem in several scientific areas. In the current contribution, we introduce a new method for performing this task, the regularized hypothesis testing (RHT) method, focusing on its use in neuroimaging research. RHT is based on the formulation of the hypothesis testing task as a Bayesian estimation problem, with the previous application of a Markovian random field. The latter allows for the incorporation of local spatial information and considers different noise models, including spatially correlated noise. In tests on synthetic data showing regular activation levels on uncorrelated noise fields, RHT furnished a true positive rate (TPR) of 0.97, overcoming the state-of-the-art morphology-based hypothesis testing (MBHT) method and the traditional family-wise error rate (FWER) method, which afforded 0.93 and 0.58, respectively. For fields with highly correlated noise, the TPR provided by RHT was 0.65, and by MBHT and FWER was 0.35 and 0.29, respectively. For tests utilizing real functional magnetic resonance imaging (fMRI) data, RHT managed to locate the activation regions when 60% of the original signal were removed, while MBHT located only one region and FWER located none.

Resumen En varias áreas científicas aparece el problema de determinar los elementos de un campo aleatorio (por ejemplo, píxeles en una imagen) en los que se puede rechazar una cierta hipótesis nula. En este artículo presentamos un nuevo método para realizar esta tarea, centrado en aplicaciones para investigación de neuroimagen. Nuestra propuesta se basa en la formulación de pruebas de hipótesis como un problema de estimación Bayesiana, usando como a priori un campo aleatorio Markoviano, que permite incorporar información espacial local y considera diferentes modelos de ruido, incluido el ruido correlacionado espacialmente. Para pruebas en datos sintéticos con niveles de activación regulares sobre campos de ruido no correlacionado, nuestro método obtiene una tasa de verdaderos positivos (TPR) de 0.97, superando al método del estado del arte MBHT y al método de control FWER que obtienen 0.93 y 0.58 respectivamente; para campos con ruido altamente correlacionado, nuestro método obtiene un TPR de 0.65, mientras que MBHT y FWER obtienen 0.35 y 0.29 respectivamente. Para pruebas con datos reales de fMRI, nuestro método localiza las regiones de activación cuando removemos 60% de la señal original, mientras que MBHT no localiza región alguna y FWER localiza una de las dos regiones.

A study on changes of the resting-state brain function network in patients with amnestic mild cognitive impairment

This study aimed to explore the structural and functional characteristics of the neural network of resting-state brain activities in patients with amnestic mild cognitive impairment (aMCI) by functional magnetic resonance imaging (fMRI) technology. Resting state fMRI scanning was performed on 10 clinically diagnosed aMCI patients and 10 healthy volunteers, and the difference in the resting-state brain activities between aMCI patients and healthy volunteers was compared using the brain function network regional homogeneity (ReHo) analysis method. Results of the ReHo analysis of aMCI patients and healthy volunteers revealed that the ReHo value significantly increased in the posterior cingulate gyrus region, medial frontal lobe, medial cortex of the prefrontal lobe, and part of the parietal lobe. Compared with the normal elderlies, ReHo decreased in aMCI patients in the left temporal lobe (middle temporal gyrus and inferior temporal gyrus), left parahippocampal gyrus, occipital lobe, lingual gyrus, precuneus, and other regions while ReHo increased in regions of the right frontal lobe (inferior frontal gyrus), left superior temporal gyrus, precentral gyrus (frontal lobe), right thalamus, left fusiform gyrus, and other regions. In the resting state, there may be regional abnormalities in brain functional areas in aMCI patients, which may be associated with cognitive impairment.

Cambios en resonancia magnética funcional en estudiantes de medicina con y sin restricción moderada de sueño / Changes in functional magnetic resonance imaging in medical students with and without moderate sleep deprivation

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<0,05) entre el ciclo de sueño regular y el de restricción moderada. La actividad cerebral en RMf con los paradigmas de atención Stroop y fluidez fonológica no mostró diferencias significativas, así como tampoco la prueba psicológica de atención d2. Discusión: Se encontró interferencia en las activaciones cerebrales de representación motora con la restricción moderada de sueño, pero no se hallaron diferencias significativas en las activaciones de atención tipo Stroop, ni en la tarea de fluencia fonológica o las pruebas de atención d2. Esto podría deberse a una insuficiente restricción del sueño o a eficientes mecanismos de compensación en los sujetos de este estudio. Conclusión: Existen diferencias en las activaciones cerebrales de representación motora en la restricción moderada del sueño medidas con RMf

OBJECTIVE: To describe the effects of moderate sleep deprivation in brain regions involved in cognitive inhibition processes, motor function, and phonological fluency using functional Magnetic Resonance Imaging (fMRI). Materials and methods: A sample of 12 under-graduate and post-graduate medical students, between 20 and 40 years, were subjected to a follow-up of the number of hours of regular sleep in order compare to a moderate sleep deprivation after a nightshift. The d2 attention test and fMRI studies were used in both groups in order to evaluate motor function, verbal fluency and cognitive inhibition, or Stroop paradigms. The moderate sleep deprivation was at least 63% with respect to the regular sleep pattern during the previous week. Results: Significant differences in brain activity were found in fMRI to measure motor function (P<0.05) comparing regular sleep cycle and moderate sleep deprivation. The brain activity with fMRI Stroop paradigms and phonological fluency showed no significant differences between the two conditions, likewise with the psychological attention test d2. Discussion: The fMRI showed interference on motor representation activations in moderate sleep deprivation. No significant differences in fMRI were found in the processes of cognitive inhibition or Stroop paradigms, in phonological fluency, or in the psychological attention test d2. These could be attributed to inadequate sleep deprivation or efficient compensation mechanisms in the subjects of this study. Conclusión: There is a difference showed in fMRI on motor representation activations in moderate sleep deprivation

Conectividad funcional en un paciente con alucinaciones complejas. Un caso de autoscopia / Functional connectivity in a patient with complex hallucinations. A case of autoscopy

La autoscopia, del griego autos (sí mismo) y skopeo (mirar), son alucinaciones complejas durante las cuales el paciente experimenta una duplicación visual de su cuerpo. El presente artículo discute algunos correlatos de conectividad cerebral obtenida por resonancia funcional en reposo, en una paciente con epilepsia refractaria y alucinaciones autoscópicas durante sus crisis. El objetivo es presentar los hallazgos por neuroimágenes funcionales de una paciente que presenta alucinaciones del tipo autoscópico. Como parte del protocolo de evaluación de pacientes con epilepsia refractaria se realiza examen de videomonitoreo electroencefalográfico, imágenes de tomografía por emisión de positrones e imágenes de resonancia magnética funcional en reposo a una paciente que sufre alucinaciones autoscópicas durante las crisis. La información obtenida por estos estudios se correlaciona con la información clínica. En la paciente, el estudio de tomografía por emisión de positrones y el videomonitoreo electroencefalográfico indican alteraciones en el lóbulo occipital derecho, hallazgos que coinciden con reportes en la literatura sobre autoscopia. La sincronización neuronal, medida por resonancia funcional, es anormal en la misma región alterada en la tomografía por emisión de positrones, permitiendo relacionar el fenómeno autoscópico con cambios de la conectividad cerebral. La paciente cuenta con características clínicas de alucinación autoscópica. La resonancia magnética indica zonas con alteraciones de la dinámica cerebral que, en el caso de la paciente, coinciden con regiones reportadas en la literatura. El presente estudio aporta evidencias sobre el papel de los mecanismos de sincronización neuronal y la percepción de alucinaciones.

Autoscopy, from Greek autos (self) and skopeo (looking at), are complex hallucinations wherein the patient feels a visual duplication of his body. The current paper presents some brain connectivity correlates, obtained from resting state functional magnetic resonance, in a patient with refractory epilepsy who suffers autoscopic hallucinations during her seizures. Introduce the functional neuroimaging findings in a patient with autoscopic hallucinations. As part of the evaluation protocol for patients with refractory epilepsy, electroencephalographic video monitoring, positron emission tomography and resting state functional magnetic resonance imaging, were done to a patient that suffers autoscopic hallucinations during her crisis. The information obtained from those studies are correlated with clinical information. In the patient, the positron emision tomography and the electroencephalographic video monitoring study indicate an injury in the right occipital lobe, findings that coincide with previous literature report about autoscopy. The neuronal synchronization, measured by functional resonance, is abnormal in the same region where is altered the positron emision tomography imaging, enabling to relate the autoscopy phenomena with brain connectivity alterations. The patient has clinical features of autoscopic hallucination. MRI indicates areas with altered brain dynamics in the case of the patient coincide with regions reported in the literature. This study provides evidence on the role of neuronal synchronization mechanisms and the perception of hallucinations.

Neuropsicología y la localización de las funciones cerebrales superiores en estudios de resonancia magnética funcional con tareas / Neuropsychology and the localization of superior brain functions in fMRI with task studies

El objetivo es destacar la capacidad de la resonancia magnética funcional con tareas para evaluar diversas funciones cerebrales superiores, mediante la ejecución de paradigmas que producen activación cerebral de las regiones involucradas. Resaltar la importancia del neuropsicólogo en la creación de paradigmas y en la interpretación de los resultados. Se realizó una revisión no sistemática de la literatura científica recogida en las bases de datos de: Rev Neurol, Neurology, Radiología, Neuroimage, J Neuroimaging, Science, Brain, Neuroscience and biobehavioral reviews, journal of neuroscience, Eur J Radiol, Magnetic resonance in medicine, Neurosurgery, Neuroimagingclin, Neuropsidologia latinoamericana, International journal of neuroscience, Science, Biol Psychiatry, Psychol Med, Arch Gen Psychiatry, Psychiatry Res Neuroimaging, Neuro Report, Neuron, J ClinExpNeuropsychol, Proc Natl Acad Sci U S A, Ann Neurol Neurobiol Aging, Neurosci Lett, Journal of Neuroscience. Los descriptores utilizados fueron "Resonancia magnética funcional", "Paradigmas" y "Neuropsicología". Se seleccionaron los artículos científicos de cualquier tipo y en español e inglés; desde el inicio de la indización de la fuente primaria hasta noviembre de 2014. Se recuperaron 42 artículos. Se analizaron todos los conceptos sobre resonancia magnética funcional, neuropsicología, funciones cerebrales superiores, áreas cerebrales activadas, paradigmas. Los mapas de activación neuronal confirman la participación simultánea de diferentes áreas cerebrales, incluso distantes, durante la ejecución de paradigmas. La participación del neuropsicólogo dentro del grupo multidisciplinario es muy importante por su conocimiento profundo de los factores involucrados en el desempeño de las diferentes tareas cognitivas potencialmente evaluables por resonancia magnética funcional.

To highlight the capacity of functional magnetic resonance imaging (fMRI) with tasks in order to measure different higher brain functions by running paradigms that produce brain activation in the regions involved. Highlighting the importance of the neuropsychologist in creating paradigms and interpreting results. A non-systematic review of the scientific literature contained in the databases was conducted: Rev Neurol, Neurology, Radiología, Neuroimage, J Neuroimaging, Science, Brain, Neuroscience and biobehavioral reviews, journal of neuroscience, Eur J Radiol, Magnetic Resonance in Medicine, Neurosurgery, Neuroimagingclin, Neuropsicologia Latinoamericana, International Journal of Neuroscience, Biol Psychiatry, Psychol Med, Arch Gen Psychiatry, Psychiatry Res Neuroimaging, Neuro Report, Neuron, J ClinExpNeuropsychol , Proc Natl Acad Sci U S A, Ann Neurol Neurobiol Aging, Neurosci Lett, Journal of Neuroscience. The descriptors used were: "functional MRI", "Paradigms" and "Neuropsychology". Papers in Spanish and English of any kind were selected since the start of indexing the primary source until November 2014. 42 articles were retrieved. The following concepts were analyzed: functional magnetic resonance imaging, neuropsychology, higher brain functions, activated brain areas paradigms. The neural activation maps confirm the simultaneous involvement of different brain areas, even distant ones, during the execution of paradigms. Neuropsychologist participation within the multidisciplinary team is very important for its deep understanding of the factors involved in the performance of different cognitive tasks potentially assessable by fMRI.

Procesamiento de la música en el primer episodio de trastorno depresivo mayor sin tratamiento / Music processing in major depressive disorder first episode without treatment

El propósito de este estudio fue registrar diferencias durante la audición de dos tipos diferentes de música en pacientes con Trastorno Depresivo Mayor (TDM), comparados con sujetos sanos, mediante imagen por resonancia magnética funcional (IRMf). La actividad cerebral con estímulos musicales ha sido investigada ampliamente en sujetos sanos, pero son escasos los estudios del procesamiento de la música en estados de patología mental, particularmente en el TDM. Los estudios en esta área interdisciplinaria proveen una nueva perspectiva de investigación para explorar los sustratos neurobiológicos del TDM. Participaron 20 sujetos de sexo masculino: 10 pacientes con TDM (34 ± 7 años) y 10 sujetos control (33 ± 7 años). Los pacientes se seleccionaron en el servicio de pre-consulta del Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz (INPRFM) de la Ciudad de México, y los sujetos control entre los trabajadores del propio Instituto que respondieron a la invitación. Todos los participantes contestaron, con fines de confirmar el diagnóstico, las escalas de ansiedad y depresión de Hamilton, los inventarios de Beck para ansiedad y depresión y el SCL-90-R. A los pacientes se les aplicó además el MINI-mental test. Para la IRMf se usó un equipo Philips Achieva de tres Teslas en el INPRFM, el análisis se hizo con el formato SPM2 usando el sistema MRIcro. Los estímulos experimentales fueron una obra musical de JS Bach validada como tranquila y otra de J Prodromidès validada como inquietante. Los resultados muestran diferencias tanto entre los grupos de sujetos como entre los tipos de música: en todos los casos se activó el área parahipocampal, la cola del núcleo caudado y la corteza temporal auditiva. Concluimos que el procesamiento neurobiológico de la música es afectado por el TDM. Se discuten las implicaciones clínicas y cognoscitivas de estos hallazgos.

The purpose of this study is the assessment of the differences in brain activity when patients with major depressive disorder (MDD) listen to two different types of music, with healthy subjects as control, by using functional magnetic resonance imaging (fMRI). Brain activity in musical stimuli with healthy subjects has been investigated extensively, but there are few neurobiologic music studies in mental illness, particularly in MDD. Studies in this area provide a new perspective on interdisciplinary research to explore the neurobiological substrates of MDD. This study involved 20 male subjects: 10 patients (34 ± 7 years), and 10 control subjects (33 ± 7 years). The MDD :atients were selected in the pre-consultation service of the National Institute of :sychiatry Ramón de la Fuente Muñiz (IN:RFM) of Mexico City, and control subjects were selected among workers of the Institute who responded to the invitation. All participants completed the Hamilton scales for anxiety and depression, Beck inventories for depression and anxiety and, the SCL-90-R. The Mini-Mental State Examination test was also administered to patients for diagnostic purposes. The fMRI was obtained by Philips Achieva 3-Tesla in the INPRF; the analysis was done using S:M2 format MRIcro system. The experimental stimuli were two pieces of music: one by JS Bach validated as quiet and another one by J Prodromidès validated as disturbing. Results show differences between both groups of subjects and between types of music. In all cases, the parahippocampal area, the tail of the caudate nucleus and the auditory temporal cortex were activated. The neurobiological processing of music is affected by MDD. We discuss the clinical and cognitive implications of these findings.

The impacts of cognitive-behavioral therapy on the treatment of phobic disorders measured by functional neuroimaging techniques: a systematic review

Objective: Functional neuroimaging techniques represent fundamental tools in the context of translational research integrating neurobiology, psychopathology, neuropsychology, and therapeutics. In addition, cognitive-behavioral therapy (CBT) has proven its efficacy in the treatment of anxiety disorders and may be useful in phobias. The literature has shown that feelings and behaviors are mediated by specific brain circuits, and changes in patterns of interaction should be associated with cerebral alterations. Based on these concepts, a systematic review was conducted aiming to evaluate the impact of CBT on phobic disorders measured by functional neuroimaging techniques. Methods: A systematic review of the literature was conducted including studies published between January 1980 and April 2012. Studies written in English, Spanish or Portuguese evaluating changes in the pattern of functional neuroimaging before and after CBT in patients with phobic disorders were included. Results: The initial search strategy retrieved 45 studies. Six of these studies met all inclusion criteria. Significant deactivations in the amygdala, insula, thalamus and hippocampus, as well as activation of the medial orbitofrontal cortex, were observed after CBT in phobic patients when compared with controls. Conclusion: In spite of their technical limitations, neuroimaging techniques provide neurobiological support for the efficacy of CBT in the treatment of phobic disorders. Further studies are needed to confirm this conclusion. .

Funções cognitivas em vítimas de afogamento: análise neuropsicológica e ressonância magnética funcional / Cognitive functions in drowning victims: neuropsychological assessment and functional magnetic resonance imaging

OBJETIVO: Avaliar o desempenho em testes neuropsicológicos e a resposta hemodinâmica cerebral medida por ressonância magnética funcional (RMf) em tarefas de memória e motora numa amostra de pacientes vítimas de afogamento com perda de consciência comparados a um grupo de indivíduos saudáveis. MATERIAL E MÉTODO: Estudamos 15 voluntários com média de idade de 23,7 anos no grupo de pacientes, selecionados a partir de amostra de 157 vítimas de afogamento, tendo como critérios de inclusão grau 3 e 4 da Escala de Afogamento (Szpilman, D. 1997) e excluindo-se aqueles com lesões estruturais cerebrais, antecedentes de alterações neurológicas ou psiquiátricas. Este grupo foi comparado a 18 voluntários saudáveis com média de idade de 25,3 anos selecionados para o grupo controle, pareados por anos de educação formal, idade e sexo. As imagens estruturais para referência anatômica (T1 3D; FLAIR 2D) e imagens funcionais axiais eco-planar, gradiente de ecos com ponderação T2*, com voxels isotrópicos de 3mm foram adquiridas em sistema de RM de 3,0 Teslas e os estímulos apresentados visualmente e sincronizados com a aquisição das imagens. O estudo de RMf foi realizado em desenho em bloco, com tarefa motora e de memória. Os dados de RMf foram préprocessados para correção de movimento, filtro espacial e temporal e foi aplicado Modelo Geral Linearizado para identificação de áreas cerebrais associadas às tarefas e produção de mapas estatísticos limiarizados (p < 0,05) representado a resposta cerebral de cada grupo, corrigidos para comparações múltiplas. Foram realizados testes ANOVA na comparação entre os dois grupos quanto às áreas cerebrais detectadas nas duas tarefas, sem e com utilização de co-variáveis obtidas de parâmetros dos testes neuropsicológicos. Além disso, investigamos a conectividade entre as regiões de redes neurais de cada paradigma através da análise de PPI e análise de correlação média de regiões da rede clássica de memória e motora entre os grupos. RESULTADOS:...

hemodynamic response measured by functional magnetic resonance imaging (fMRI) on memory and motor tasks in a sample of drowning victims with loss of consciousness compared to a group of healthy individuals. MATERIAL AND METHODS: We studied 15 volunteers (six men; mean age: 23.7 years) enlisted in the group of patients, which were selected from a sample of 157 drowning victims, with the inclusion criteria grade 3 and 4 Scale Drowning (Szpilman D., 1997) and excluding those with structural brain lesions , history of neurological or psychiatric disorders. This group was compared to 18 healthy volunteers (five men; mean age: 25.3 years matched for years of education, age and sex (control group). Structural images for anatomical reference (T1 3D, 1mm isotropic voxels; FLAIR 2D, voxels 1.2x1.2x5mm) and functional imaging axial echo - planar gradient echo T2*- weighted (Blood Oxygenation Level Dependent ) with 3mm isotropic voxels were acquired in MR system of 3.0 Tesla using a 8 Ch head coil, the stimuli presented visually and synchronized with image acquisition (Zurc & Zurc , São Paulo - Brazil). The study was conducted using fMRI block design, with motor task (finger tapping) and memory (visual recognition - part of the International Consortium for Brain Mapping). Subjects' performance in the fMRI tasks were recorded using a response box and visual observation of hand movement frequency. fMRI data were preprocessed for motion correction , spatial and temporal filter was applied and General Linear Model (GLM) was used for identification of brain areas associated with the tasks. Statistical thresholded maps (p < 0.05) representing group response to each task were corrected for multiple comparisons. ANOVA tests were performed to compare the group maps in the two tasks, with and without using covariates obtained from neuropsychological. Furthermore, we investigated the connectivity between regions of each neural network paradigm by analyzing psychophysiological...

Volumen y función hipocampal en epilepsia del lóbulo temporal medial / Volume and hippocampal function in medial temporal lobe epilepsy

Introducción: La resonancia magnética funcional (fMRI ) es fundamental en la evaluación de lenguaje y memoria en pacientes con epilepsia del lóbulo temporal. También ha permitido observar cómo las estructuras de la corteza medial temporal tienen lateralidad funcional de acuerdo con la dominancia del lenguaje, con un hemisferio especializado tanto en los aspectos expresivos y receptivos del lenguaje como en la memorización de material verbal. Objetivo: Relacionar la integridad del hipocampo izquierdo con el grado de asimetría de la dominancia del lenguaje vista por fMRI. Materiales y métodos: Mediante resonador de 1,5 T se obtienen imágenes con información en T1 volumétricas y EPI con información en T2 durante la ejecución de paradigmas de codificación de escenas complejas, generación de palabras y decisión semántica en un conjunto de 12 individuos sanos y en diferentes pacientes candidatos a cirugía de epilepsia. Resultados: La volumetría automatizada de los hipocampos del grupo control no muestra asimetría significativa. En los diferentes pacientes con esclerosis hipocampal se obtienen índices numéricos que corroboran la implicación de la integridad del hipocampo izquierdo con los índices de asimetría en las pruebas de lenguaje. Conclusiones: En los resultados de la implementación del protocolo de memoria y lenguaje por fMRI para pacientes con epilepsia del lóbulo temporal se destacan las evidencias obtenidas acerca de la implicación del hipocampo en la red del lenguaje y el efecto que tiene la afectación del hipocampo izquierdo en los patrones de migración del lenguaje hacia el hemisferio contralateral.

Introduction: The functional Magnetic Resonance (fMRI) is important in the evaluation of language and memory of patients with temporal lobe epilepsy. The fMRI has also enabled to observe how the structures in the medial temporal cortex have functional laterality according to the dominance of language, with a hemisphere which is specialized in the expressive and receptive aspects of language and the encoding of verbal material. Objective: To relate the left hippocampus integrity with the degree of asymmetry of the language dominance seen by fMRI. Materials and methods: Images with T1 volumetric information and EPI with T2 information are obtained using a 1.5T magnetic resonator, during the execution of complex scenes encoding paradigms, as well as during the generation of words and a semantic decision in a set of 12 control subjects and different patients who are potential candidates for epilepsy surgery. Results: The automatized volumetric properties of the control group hippocampus do not show significant asymmetry. Indifferent patients with hippocampal sclerosis, numerical indexes are obtained, which are in accordance with the implication of the integrity of the left hippocampus with the asymmetry indexes in the language paradigms. Conclusions: Among the results of the implementation of the memory and language protocol, using fMRI for patients with temporal lobe epilepsy, one can emphasize the evidences obtained using fMRI regarding the implications of the left hippocampus in the language network and the effects of its dysfunction in the migration patterns of language towards the contralateral hemisphere.

Levodopa versus non-levodopa brain language fMRI in Parkinson's disease / RMf de linguagem na doença de Parkinson: levodopa versus não levodopa

Objective: To identify the effect of levodopa in language areas in Parkinson's disease patients. Methods: We evaluated 50 patients with mild to moderate Parkinson's disease, age and gender paired to 47 healthy volunteers. We selected two homogeneous groups of 18 patients taking levodopa and 7 no levodopa patients. The functional magnetic resonance imaging verbal fluency task, with low and high cognitive demands, was performed at a 3T magnetic resonance imaging equipment. Data was analyzed with XBAM software for group maps and ANOVA comparison. Results: Patients without levodopa had more activation than the ones with levodopa in the medial frontal and in the left frontal and parieto-occipital areas. The striatal activation in patients taking levodopa had similar result of the activation detected in the healthy volunteer group. Parietooccipital areas were less activated in the levodopa group than in the no levodopa one. Conclusion: Parkinson's disease patients without levodopa replacement, during a verbal fluency effort, had more diffuse and intense cerebral activation in left hemisphere, mainly in the frontal and parieto-occipital areas. The striatal activation in verbal fluency of patients with levodopa intake was more similar to the activation found in healthy volunteers. These initial evidences suggested a role of levodopa inhibiting activation in parieto-occipital compensating areas.

Objetivo: Identificar o efeito da levodopa nas áreas de linguagem em pacientes com doença de Parkinson. Métodos: Foram avaliados 50 pacientes com doença de Parkinson leve a moderada e pareados, por gênero e idade, a 47 voluntários saudáveis. Foram selecionados dois grupos homogêneos de 18 pacientes que usavam e 7 que não usavam levodopa. O exame de ressonância magnética funcional, com tarefa de fluência verbal por geração de palavras de maiores e menores demandas cognitivas, foi realizado em equipamento de 3T. Os dados foram analisados pelo programa XBAM para os mapas de grupo e as comparações ANOVA. Resultados: Os pacientes sem utilização de levodopa tiveram maior ativação nas áreas frontais mediais e esquerdas e áreas parieto-occipitais que com levodopa. A ativação estriatal nos pacientes em uso de levodopa foi similar à detectada no grupo de voluntários saudáveis. Conclusão: Pacientes com doença de Parkinson, sem utilização de levodopa durante o esforço da fluência verbal, tiveram ativação mais difusa e intensa, principalmente no hemisfério esquerdo, em áreas frontais e parieto-occipitais. A atividade cerebral estriatal na fluência verbal de pacientes em uso de levodopa foi semelhante a dos voluntários saudáveis. Essas evidências iniciais sugerem um papel inibidor da levodopa na ativação compensatória de áreas parieto-occipitais.

Current methodological designs of fMRI studies of panic disorder: can data be compared?

Panic disorder (PD) is a pluridimensional condition that leads to psychological suffering. Due to advances in neuroimaging techniques, important contributions have been made in the understanding of the neurobiological basis of PD. However, because of diverging research designs and protocols, more conclusive data concerning the neurocircuitry of PD remain difficult to achieve. To address this issue, a bibliographical search was performed using the Institute for Scientific Information Web of Science and Medline/PubMed databases. Fifteen articles were found, and their research methodology including sample, comorbidity, gender, and pharmacological criteria were explored. Although current functional magnetic resonance imaging studies of PD constitute fundamental tools for health sciences, more uniform research protocols must be implemented to provide more consistent and conclusive data concerning the neural substrates of PD.

Resonancia magnética funcional en pacientes adultos eutímicos con trastorno bipolar tipo I: una visión neuropsicológica y neurofuncional / Functional Magnetic Resonance Imaging in euthymic Adult Patients with Bipolar Disorder Type I: Neuropsychological and Neurofunctional Aspects

Introducción: En la última década se han realizado varios estudios de resonancia magnética funcional en la fase eutímica del trastorno bipolar tipo I; por lo tanto, es necesario hacer una revisión crítica de los hallazgos reportados. Métodos: Revisión de la literatura, consistente en búsqueda, lectura y análisis de los estudios de resonancia magnética funcional en adultos eutímicos con trastorno bipolar tipo I en las bases de datos científicas PubMed, EMBASE, SciELO y Lilacs, sin límite cronológico. Resultados: Los hallazgos neuroanatómicos y neuropsicológicos se presentan en dos bloques: primero, memoria de trabajo con paradigmas N Back y Stenberg y, segundo, función ejecutiva con interferencia en atención selectiva o pruebas tipo Stroop (palabra/color, numérico y emocional) y control inhibitorio con pruebas go/no go. Conclusiones: Los resultados fueron contradictorios por diferencias en los paradigmas, criterios de inclusión, síntomas residuales, medicamentos e historia de psicoactivos. En pruebas Stroop y de memoria de trabajo se identificó una disfunción prefrontal en comparación con los controles (específicamente en la región dorsolateral), por lo que fue propuesta como un rasgo característico del trastorno. La región frontopolar (AB 10) parece ser clave en la disfunción frontal; por su parte, el cíngulo anterior, la corteza parietal y la prefrontal ventral necesitan ser replicadas en investigaciones posteriores en las que haya un mejor control de los factores de confusión.

Introduction: Several studies using functional magnetic resonance imaging during the euthymic phase of bipolar disorder type I have been performed in the last decade. A critical review of the findings is therefore required. Methods: The major databases (Pubmed, EMBASE, Lilacs, and Scielo) were consulted searching studies of fMRI in euthymic adults with Bipolar disorder type I without timeframe limits. Results: The neuroanatomical and neuropsycholo gical findings are presented in two parts: 1) working memory with N_back and Stenberg paradigms, and 2) Executive function with interference in selective attention or Stroop test (word / color, counting and emotional) and inhibitory control with go / no go tasks. Conclusions: The results were contradictory due to differences in paradigms, inclusion criteria, residual symptoms, and history of drugs. Prefrontal dysfunction was identified in the Stroop test and in working memory tasks compared with controls (specifically dorsolateral region) which has been proposed as a feature of the disorder. Frontopolar area (BA 10) appears to be important in frontal dysfunction. Findings in areas such as the anterior cingulate and parietal and ventral prefrontal cortex need to be replicated in subsequent research with a closer control of confounding factors.

Implementación y validación de protocolo de estimulación por comprensión de lenguaje oral en resonancia magnética funcional: resultados preliminares / Implementation and validation of a stimulation protocol for oral language comprehension using functional magnetic resonance imaging: preliminary results

This study aimed at implementing a stimulation protocol using functional Magnetic Resonance Imaging (fMRI), in a Hospital in Valparaiso (V Region), Chile, to detect cortical areas activated in oral language comprehension. Seven healthy volunteers participated in this study. Average t-score and signal variation were 6.3 +/- 0.3 and 0.5 +/- 0.1 percent, respectively. In spite of these low values, activations were obtained in Wernicke area, middle temporal gyrus, and Heschl s gyrus. The extension of activated areas was small, 5.06 +/- 2.99 cm3, probably due to amplifer low signal-to-noise ratio (SNR), in addition to the cognitive complexity of the task, and to the ambient acoustic noise. Successful implementation of fMRI protocols of language comprehension is possible in a clinical context in Chile without any additional resources.

Nuestro objetivo fue implementar un protocolo de estimulación en resonancia magnética funcional en un Hospital de Valparaíso, V Región de Chile, para detectar las áreas corticales activadas en la comprensión del lenguaje oral. Siete voluntarios sanos participaron de este estudio. El t-score y variación de señal alcanzado fue de 6.3 0.3 y 0.5 +/- 0.1 por ciento respectivamente. A pesar de estos bajos valores, las activaciones se registraron en el área Wernicke, circunvolución temporal media y circunvolución d e Heschl. La extensión de las activaciones fue pequeña, 5.06 +/- 2.99 cm³, probablemente debido a la baja relación señal ruido del resonador (SNR), además de la complejidad cognitiva de la tarea y el ruido acústico ambiente. Nuestros resultados indican que la implementación de la RMf en comprensión del lenguaje es posible de realizar en Chile sin recursos adicionales.