Neuroanatomical and psychological considerations in temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is associated with a variety of structural and psychological alterations. Recently, there has been renewed interest in using brain tissue resected during epilepsy surgery, in particular `non-epileptic¿ brain samples with normal histology that can be found alongside epileptic tissue in the same epileptic patients ¿ with the aim being to study the normal human brain organization using a variety of methods. An important limitation is that different medical characteristics of the patients may modify the brain tissue. Thus, to better determine how `normal¿ the resected tissue is, it is fundamental to know certain clinical, anatomical and psychological characteristics of the patients. Unfortunately, this information is frequently not fully available for the patient from which the resected tissue has been obtained ¿ or is not fully appreciated by the neuroscientists analyzing the brain samples, who are not necessarily experts in epilepsy. In order to present the full picture of TLE in a way that would be accessible to multiple communities (e.g., basic researchers in neuroscience, neurologists, neurosurgeons and psychologists), we have reviewed 34 TLE patients, who were selected due to the availability of detailed clinical, anatomical, and psychological information for each of the patients. Our aim was to convey the full complexity of the disorder, its putative anatomical substrates, and the wide range of individual variability, with a view toward: (1) emphasizing the importance of considering critical patient information when using brain samples for basic research and (2) gaining a better understanding of normal and abnormal brain functioning. In agreement with a large number of previous reports, this study (1) reinforces the notion of substantial individual variability among epileptic patients, and (2) highlights the common but overlooked psychopathological alterations that occur even in patients who become ¿seizure-free¿ after surgery. The first point is based on pre- and post-surgical comparisons of patients with hippocampal sclerosis and patients with normal-looking hippocampus in neuropsychological evaluations. The second emerges from our extensive battery of personality and projective tests, in a two-way comparison of these two types of patients with regard to pre- and post-surgical performance.This work was supported by grants from the following entities: Grant PID2021-127924NB-I00 funded by MCIN/AEI/10.13039/501100011033; Centro de Investigación en Red sobre Enfermedades Neurodegenerativas (CIBERNED, CB06/05/0066); and CSIC Interdisciplinary Thematic Platform (PTI) Cajal Blue Brain (PTI-BLUEBRAIN; Spain). RA was supported by ANDIA grant #0011-3947-2021-000023 from the Gobierno de Navarra

Estudio integrado de las características histopatológicas y clínicas en pacientes con enfermedad de Alzheimer

Memoria de Tesis doctoral presentada por Diana Furcila, para obtener el doctorado (Mención en Psicología de la Salud) por la Escuela Internacional de doctorado (EIDUNED-UNED), realizada bajo la dirección de Dr. Javier DeFelipe Oroquieta, Dr. Emilio Ambrosio Flores y Dra. Lidia Alonso-Nanclares .-- 207 pagesEstudio integrado de las características histopatológicas y clínicas en pacientes con enfermedad de Alzheimer La enfermedad de Alzheimer (EA) se define como un deterioro cognitivo gradual e irreversible, cuyas fases avanzadas se caracterizan por una pérdida de las funciones cerebrales superiores del sujeto (Valls-Pedret et al., 2010). Durante los procesos neurodegenerativos de la EA, la memoria es la primera función en comenzar a mostrar signos de deterioro. Las principales huellas microanatómicas son la presencia de ovillos neurofibrilares de proteína tau hiperfosforilada (PHFTau) en el interior de las neuronas, y la agregación extracelular de la proteína β-amiloide (Aβ). No obstante, la mera presencia de estas proteínas no induce necesariamente a la EA. La formación hipocampal es una de las primeras regiones en mostrar alteraciones en la EA, siendo una zona de estudio relevante dadas las funcionalidades que soporta, como la formación de nuevas memorias, y la orientación espacial y temporal, que se ven alteradas en etapas iniciales de la enfermedad. El objetivo principal de esta tesis es analizar las alteraciones histopatológicas en la formación del hipocampo de pacientes con la EA, explorando, además, su posible relación mediante una herramienta informática desarrollada para ello. En primer lugar, se ha analizado la densidad de las neuronas de PHFTau-ir y de las placas de Aβ-ir, así como la posible pérdida neuronal, en el giro dentado (GD), CA3, CA1 y subículo de 11 pacientes con EA. Usando métodos cuantitativos estereológicos se encontró que la densidad de neuronas en CA1 de pacientes con EA estaba reducida, especialmente en aquellos casos con esclerosis del hipocampo, siendo además la región más afectada por la presencia de numerosos elementos PHFTau-ir y placas Aβ-ir. El subículo no mostró cambios en la densidad neuronal, pero expresó niveles moderados de neuronas PHFTau-ir y placas Aβ-ir, mientras que el GD y CA3 estaban menos afectados por la presencia de estos elementos patológicos. En segundo lugar, se ha llevado a cabo un análisis detallado de la patología neurofibrilar y la patología amiloide en la región CA1 mediante técnicas de microscopía confocal, poniendo de manifiesto cuatro hallazgos principales. Primero, a pesar de que la expresión de placas y de neuronas PHFTau-ir presenta una gran variedad de patrones, la capa piramidal de la región medial de CA1 contiene el mayor número tanto de placas como de neuronas PHFTau-ir. Segundo, una gran proporción de placas Aβ-ir también presentaban PHFTau-ir, mientras que las placas que carecían de inmunorreactividad frente a Aβ (marcadas únicamente con PHFTau-pS396 o PHFTau-AT8) fueron escasas. Tercero, todas las placas que contenían alguna de las dos isoformas de PHFTau, expresaba también la otra, es decir, si una placa contenía PHFTau-pS396, también contenía PHFTau-AT8, y viceversa. Cuarto, el estudio de co-localización de ambas isoformas de PHFTau en las neuronas de CA1 reveló que la mayoría de las neuronas analizadas expresaban solamente PHFTau-pS396. Asimismo, la mayoría de las neuronas PHFTau-ir se identificaron como células piramidales. Por último, el desarrollo y la aplicación de una herramienta interactiva de visualización de datos, InTool Explorer, facilitó la visualización detallada de los datos obtenidos de los pacientes con EA respecto a su información clínica, demográfica y las características histopatológicas. Asimismo, gracias a InTool Explorer se pudo encontrar una posible relación inversa entre la co-expresión de neuronas y la co-localización de placas: aquellos casos con más placas Aβ-ir presentaban un menor porcentaje de placas que muestran co-localización entre Aβ y PHFTau, así como un menor porcentaje de neuronas que co-expresan ambas isoformas de la proteína PHFTau, habiendo un mayor número de neuronas PHFTau-pS396-ir. Por el contrario, los casos que expresan un menor número de placas Aβ-ir presentan un mayor porcentaje de placas que muestran co-localización entre Aβ y PHFTau, así como un mayor porcentaje de neuronas que co-expresan ambas isoformas de la proteína PHFTau, disminuyendo el número de neuronas que expresan PHFTau-pS396.El presente trabajo de investigación ha sido financiado por el Ministerio de Ciencia, Innovación y Universidades (SAF 2015-66603-P y TIN2017-83132-C2), CIBERNED (Centro de investigación Biomédica en Red, Enfermedades Neurodegenerativas) con código 2013/07; el proyecto Alzheimer´s ASsociation (ZEN-15-321663), el proyecto Cajal Blue Brain de la Universidad Politécnica de Madrid (PINV-18-XEOGHQ-19-4QTEBP),así como el proyecto to Human Brain Project (720270 SGA1 y 785907 SGA2)

A Study of Amyloid-ß and Phosphotau in Plaques and Neurons in the Hippocampus of Alzheimer's Disease Patients

The main pathological hallmarks in Alzheimer's disease (AD) are the presence of extracellular amyloid plaques, primarily consisting of amyloid-ß (Aß) peptide, and the accumulation of paired helical filaments of hyperphosphorylated tau protein (PHF-Tau) within neurons. Since CA1 is one of the most affected regions in AD, mainly at early stages, we have performed a detailed analysis of the CA1 region from 11 AD patients (demented and clinically similar; Braak stages IV-VI) to better understand the possible relationship between the presence and distribution of different neurochemical types of Aß plaques and PHF-Tau immunoreactive (- ir) neurons. Hence, we have examined hippocampal sections in confocal microscopy images from double and triple-immunostained sections, to study labeled plaques and PHF-Tau-ir neurons using specific software tools. There are four main findings in the present study. First, the pyramidal layer of proximal CA1 (close to CA2) contains the smallest number of both plaques and PHF-Tau-ir neurons. Second, a large proportion of Aß-ir plaques were also characterized by the presence of PHF-Tau-ir. Third, all plaques containing one of the two PHF-Tau isoforms also express the other isoform, that is, if a plaque contains PHFpS396, it also contains PHFAT8, and vice versa. Fourth, the coexpression study of both PHF-Tau isoforms in CA1 neurons revealed that most of the labeled neurons express only PHFpS396. Our findings further support the idea that AD is not a unique entity even within the same neuropathological stage, since the microanatomical/neurochemical changes that occur in the hippocampus greatly vary from one patient to anotherThis work was supported by a grant from the Alzheimer’s Association (ZEN-15-321663) and by grants from the Spanish Ministry of Economy, Industry and Competitiveness (SAF 2015-66603-P), the Cajal Blue Brain Project (Spanish partner of the Blue Brain Project initiative from EPFL) and Centro de Investigacion´ Biomedica en Red sobre Enfermedades Neurodegene-rativas (CIBERNED, Spain, CB06/05/0066)

Subregional Density of Neurons, Neurofibrillary Tangles and Amyloid Plaques in the Hippocampus of Patients With Alzheimer's Disease

A variety of anatomical alterations have been reported in the hippocampal formation of patients with Alzheimer's Disease (AD) and these alterations have been correlated with cognitive symptoms in the early stages of the disease. Major hallmarks in AD are the presence of paired helical filaments of tau protein (PHFTau) within neurons, also known as neurofibrillary tangles (NFTs), and aggregates of amyloid-ß protein (Aß) which form plaques in the extracellular space. Nevertheless, how the density of plaques and NFTs relate to the severity of cell loss and cognitive decline is not yet clear. The aim of the present study was to further examine the possible relationship of both Aß plaques and NFTs with neuronal loss in several hippocampal fields (DG, CA3, CA1, and subiculum) of 11 demented AD patients. For this purpose, using stereological techniques, we compared neuronal densities (Nissl-stained, and immunoreactive neurons for NeuN) with: (i) numbers of neurons immunostained for two isoforms of PHFTau (PHFTau-AT8 and PHFTau-pS396); and (ii) number of Aß plaques. We found that CA1 showed the highest number of NFTs and Aß plaques, whereas DG and CA3 displayed the lowest number of these markers. Furthermore, AD patients showed a variable neuronal loss in CA1 due to tangle-related cell death, which seems to correlate with the presence of extracellular tangles.This work was supported by grants from the following entities: the Spanish ‘‘Ministerio de Ciencia, Innovación y Universidades’’ (grant PGC2018-094307-B-I00); Centro de Investigación en Red Sobre Enfermedades Neurodegenerativas (CIBERNED, CB06/05/0066, Spain); Fundación por un Mañana Sin Alzheimer (León, Spain) and; the Alzheimer’s Association (ZEN-15321663)

Interactive exploratory data analysis tool in Alzheimer’s disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive cognitive impairment, and a variety of neuropathological changes, which are not homogenous between different brain regions within a given patient or between patients. The availability of techniques to explore the brain provides neuroscientists a wealth of data that is difficult to analyze, as a result of both its volume and its complexity. In order to overcome this problem, we propose to apply a new interactive exploratory data analysis tool, MorExAn (Morphology Exploratory Analyzer), which has been specifically designed to facilitate the study of complex neuroscientific data. In the present study, we used brain tissue from 10 patients with AD (age range 76 - 90 years old). We included quantitative stereological data of several histological features (e.g., neuron and plaques density) obtained from different hippocampal regions, as well as neuropsychological data and common clinical variables. Simultaneous analysis of data using MorExAn allows researchers to immediately detect possible differences between regions and relationships between different types of data. Thus, MorExAn provide us the possibility to relate histopathological data with neuropsychological and clinical variables. The aid of this interactive visualization tool brings us the possibility to find unexpected conclusions beyond the insight provided by simple statistics analysis, as well as to improve neuroscientists’ productivity

Phospho-tau changes in the human CA1 during Alzheimer's disease progression

Despite extensive studies regarding tau phosphorylation progression in both human Alzheimer's disease cases and animal models, the molecular and structural changes responsible for neurofibrillary tangle development are still not well understood. Here, by using the antibodies AT100 (recognizes tau protein phosphorylated at Thr212 and Ser214 in the proline-rich region) and pS396 (recognizes tau protein phosphorylated at serine residue 396 in the C-terminal region), we examined phospho-tau immunostaining in neurons from the hippocampal CA1 region of 21 human cases with tau pathology ranging from Braak stage I to VI. Our results indicate that the AT100/pS396 ratio decreases in CA1 in accordance with the severity of the disease, along with its colocalization. We therefore propose the AT100/pS396 ratio as a new tool to analyze the tau pathology progression. Our findings also suggest a conformational modification in tau protein that may cause the disappearance of the AT100 epitope in the late stages of tau pathology, which may play a role in the toxic tangle aggregation. Thus, this study provides new insights underlying the stages for the formation of neurofibrillary tangles in Alzheimer's disease.This work was supported by grants from the following entities: the Spanish Ministerio de Ciencia, Innovación y Universidades (Grants SAF 2015-66603-P and Cajal Blue Brain Project, Spanish partner of the Blue Brain Project initiative from EPFL, Switzerland to JDF and Grant BFU 2016-77885-P to JA and FH), Comunidad de Madrid (S2017/BMD-3700) to JA and FH, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, Spain, CB06/05/0066) and the Alzheimer’s Association (ZEN-15-321663) to JDF

InTool Explorer: An Interactive Exploratory Analysis Tool for Versatile Visualizations of Neuroscientific Data

The bottleneck for progress in many research areas within neuroscience has shifted from the data acquisition to the data analysis stages. In the present article, we propose a method named InTool Explorer that we have developed to perform interactive exploratory data analysis, focusing on neuroanatomy as an example of its utility. This tool is freely-available software that has been designed to facilitate the study of complex neuroscience data. InTool Explorer requires no more than an internet connection and a web browser. The main contribution of this tool is to provide a user-designed canvas for data visualization and interaction, to perform specific exploratory tasks according to the user needs. Moreover, InTool Explorer permits visualization of the datasets in a very dynamic and versatile way using a linked-card approach. For this purpose, the tool allows the user to select among different predefined card types. Each card type offers an abstract data representation, a filtering tool or a set of statistical analysis methods. Additionally, InTool Explorer makes it possible linking raw images to the data. These images can be used by InTool Explorer to define new customized filtering cards. Another significant contribution of this tool is that it allows fast visualization of the data, error finding, and re-evaluation to establish new hypotheses or new lines of research. Thus, regarding its practical application in the laboratory, InTool Explorer provides a new opportunity to study and analyze neuroscience data prior to any statistical analysis being carried out.This work was supported by grants from the following entities:(1) the Spanish Ministry of Science, Innovation and Universities:SAF 2015-66603-P, TIN2017-83132-C2, and the Cajal BlueBrain Project, Spanish partner of the Blue Brain Projectinitiative from EPFL (Switzerland); (2) Centro de Investigación en Red sobre Enfermedades Neurodegenerativas (CIBERNED,Spain, CB06/05/0066); (3) the European Union’s Horizon 2020 Research and Innovation program under specific GrantAgreement No. 720270 (Human Brain Project SGA1) and No.785907 (Human Brain Project SGA2); and (4) UniversidadPolitécnica de Madrid (PINV-18-XEOGHQ-19-4QTEBP)

InTool Explorer: an interactive exploratory analysis tool for versatile visualizations of neuroscientific data

The bottleneck for progress in many research areas within neuroscience has shifted from the data acquisition to the data analysis stages. In the present article, we propose a method named InTool Explorer that we have developed to perform interactive exploratory data analysis, focusing on neuroanatomy as an example of its utility. This tool is freely-available software that has been designed to facilitate the study of complex neuroscience data. InTool Explorer requires no more than an internet connection and a web browser. The main contribution of this tool is to provide a user-designed canvas for data visualization and interaction, to perform specific exploratory tasks according to the user needs. Moreover, InTool Explorer permits visualization of the datasets in a very dynamic and versatile way using a linked-card approach. For this purpose, the tool allows the user to select among different predefined card types. Each card type offers an abstract data representation, a filtering tool or a set of statistical analysis methods. Additionally, InTool Explorer makes it possible linking raw images to the data. These images can be used by InTool Explorer to define new customized filtering cards. Another significant contribution of this tool is that it allows fast visualization of the data, error finding, and re-evaluation to establish new hypotheses or new lines of research. Thus, regarding its practical application in the laboratory, InTool Explorer provides a new opportunity to study and analyze neuroscience data prior to any statistical analysis being carried out

Data_Sheet_1_Neuroanatomical and psychological considerations in temporal lobe epilepsy.zip

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is associated with a variety of structural and psychological alterations. Recently, there has been renewed interest in using brain tissue resected during epilepsy surgery, in particular ‘non-epileptic’ brain samples with normal histology that can be found alongside epileptic tissue in the same epileptic patients — with the aim being to study the normal human brain organization using a variety of methods. An important limitation is that different medical characteristics of the patients may modify the brain tissue. Thus, to better determine how ‘normal’ the resected tissue is, it is fundamental to know certain clinical, anatomical and psychological characteristics of the patients. Unfortunately, this information is frequently not fully available for the patient from which the resected tissue has been obtained — or is not fully appreciated by the neuroscientists analyzing the brain samples, who are not necessarily experts in epilepsy. In order to present the full picture of TLE in a way that would be accessible to multiple communities (e.g., basic researchers in neuroscience, neurologists, neurosurgeons and psychologists), we have reviewed 34 TLE patients, who were selected due to the availability of detailed clinical, anatomical, and psychological information for each of the patients. Our aim was to convey the full complexity of the disorder, its putative anatomical substrates, and the wide range of individual variability, with a view toward: (1) emphasizing the importance of considering critical patient information when using brain samples for basic research and (2) gaining a better understanding of normal and abnormal brain functioning. In agreement with a large number of previous reports, this study (1) reinforces the notion of substantial individual variability among epileptic patients, and (2) highlights the common but overlooked psychopathological alterations that occur even in patients who become “seizure-free” after surgery. The first point is based on pre- and post-surgical comparisons of patients with hippocampal sclerosis and patients with normal-looking hippocampus in neuropsychological evaluations. The second emerges from our extensive battery of personality and projective tests, in a two-way comparison of these two types of patients with regard to pre- and post-surgical performance.</p