Person: Muñoz Céspedes, Alberto
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First Name
Alberto
Last Name
Muñoz Céspedes
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Biología Celular
Area
Biología Celular
Identifiers
8 results
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Item High levels of 27‑hydroxycholesterol results in synaptic plasticity alterations in the hippocampus(Scientific Reports, 2021) Loera‑Valencia, Raul; Vazquez‑Juarez, Erika; Muñoz Céspedes, Alberto; Gerenu, Gorka; Gómez‑Galán, Marta; Lindskog, Maria; DeFelipe, Javier; Cedazo‑Minguez, Angel; Merino‑Serrais, PaulaAlterations in brain cholesterol homeostasis in midlife are correlated with a higher risk of developing Alzheimer’s disease (AD). However, global cholesterol-lowering therapies have yielded mixed results when it comes to slowing down or preventing cognitive decline in AD. We used the transgenic mouse model Cyp27Tg, with systemically high levels of 27-hydroxycholesterol (27-OH) to examine longterm potentiation (LTP) in the hippocampal CA1 region, combined with dendritic spine reconstruction of CA1 pyramidal neurons to detect morphological and functional synaptic alterations induced by 27-OH high levels. Our results show that elevated 27-OH levels lead to enhanced LTP in the Schafer collateral-CA1 synapses. This increase is correlated with abnormally large dendritic spines in the stratum radiatum. Using immunohistochemistry for synaptopodin (actin-binding protein involved in the recruitment of the spine apparatus), we found a signifcantly higher density of synaptopodinpositive puncta in CA1 in Cyp27Tg mice. We hypothesize that high 27-OH levels alter synaptic potentiation and could lead to dysfunction of fne-tuned processing of information in hippocampal circuits resulting in cognitive impairment. We suggest that these alterations could be detrimental for synaptic function and cognition later in life, representing a potential mechanism by which hypercholesterolemia could lead to alterations in memory function in neurodegenerative diseases.Item Stellate cell computational modeling predicts signal fltering in the molecular layer circuit of cerebellum(Scientific Reports, 2021) Rizza, Martina Francisca; Locatelli, Francesca; Masoli, Stefano; Sánchez‑Ponce, Diana; Muñoz Céspedes, Alberto; Prestori, Francesca; D’Angelo, EgidioThe functional properties of cerebellar stellate cells and the way they regulate molecular layer activity are still unclear. We have measured stellate cells electroresponsiveness and their activation by parallel fber bursts. Stellate cells showed intrinsic pacemaking, along with characteristic responses to depolarization and hyperpolarization, and showed a marked short-term facilitation during repetitive parallel fber transmission. Spikes were emitted after a lag and only at high frequency, making stellate cells to operate as delay-high-pass flters. A detailed computational model summarizing these physiological properties allowed to explore diferent functional confgurations of the parallel fber—stellate cell—Purkinje cell circuit. Simulations showed that, following parallel fber stimulation, Purkinje cells almost linearly increased their response with input frequency, but such an increase was inhibited by stellate cells, which leveled the Purkinje cell gain curve to its 4 Hz value. When reciprocal inhibitory connections between stellate cells were activated, the control of stellate cells over Purkinje cell discharge was maintained only at very high frequencies. These simulations thus predict a new role for stellate cells, which could endow the molecular layer with low-pass and band-pass fltering properties regulating Purkinje cell gain and, along with this, also burst delay and the burst-pause responses pattern.- Project number: 208
Item Aplicación de la clase invertida en la asignatura Biología Celular e Histología(2020) Gutiérrez Cañas, Irene; Carrión Caballo, Mar; Juarranz Moratilla, Yasmina; Lamana Domínguez, Amalia; López Redondo, Jesús María; Morona Arribas, Ruth; Muñoz Céspedes, Alberto; Ortega Moreno, Álvaro Dario; Pérez García, Selene; Pérez Gomariz, Rosa MaríaLa clase invertida o clase al revés, también conocida por el anglicismo flipped classroom, es una metodología docente en la que, como su nombre indica, se invierten los procesos que clásicamente tienen lugar dentro y fuera del aula. De manera que se pasa de una clase centrada en el profesor, como transmisor de la información y con un alumno receptor pasivo de la información cuyo trabajo fuera del aula consiste en la realización de tareas, a un modelo en el que el alumno, debe recibir y asimilar la información que le es facilitada previamente a la clase. En el aula, los alumnos resuelven dudas y realizan tareas, en muchos casos en equipo, de manera que el trabajo en el aula pasa a estar centrado en el alumno, que debe ser responsable de su propio aprendizaje. Los profesores que ya aplican esta metodología en distintos niveles educativos, se muestran muy satisfechos con el aumento del rendimiento de los estudiantes, la gran aceptación que tiene esta metodología, el aumento del aprendizaje significativo, es decir, la capacidad de relacionar los conocimientos previos con los nuevos y ser capaces de aplicar lo aprendido para la resolución de problemas. La asignatura “Biología Celular e Histología” del Grado en Biología se imparte con carácter anual durante el primer curso del grado, con una carga docente de 12 ECTS. Cada año se matriculan en la asignatura más de 400 alumnos, 300 en primera matrícula. Los contenidos teóricos que deben adquirir los alumnos son extensos y complejos, lo que supone una notable carga de trabajo para los alumnos que, si se limitan a una mera asistencia pasiva a clase, no son capaces de obtener un aprovechamiento óptimo de los contenidos y por tanto obtener buenos resultados. Además de esos contenidos teóricos, los alumnos deben adquirir unos contenidos prácticos mediante 5 sesiones de laboratorio de Biología Celular y 9 sesiones de laboratorio de Histología. Existen varios profesores implicados en la docencia teórica de esta asignatura, ya que los alumnos matriculados se dividen en 6 grupos y en algunos casos, la docencia se divide entre dos profesores, uno encargado de la parte de Biología Celular y otro de la parte de Histología. Cada profesor tiene su propio perfil docente, pero todos basamos nuestras clases en una metodología tradicional de clase magistral, es decir, una docencia centrada en el profesor, como foco transmisor de información que el alumno debe asimilar. Todos utilizamos el Campus Virtual donde colocamos las presentaciones que utilizamos en clase y donde organizamos las sesiones de seminarios. En general, año tras año, los profesores de esta asignatura observamos una falta de implicación de los alumnos en su propio aprendizaje, de manera que reciben la información de manera pasiva, escuchando al profesor, en muchos casos sin ni siquiera tomar apuntes. Esta pasividad y escasa implicación del alumnado conlleva unos resultados reflejados en las calificaciones globales generalmente decepcionantes, y que a nuestro juicio son susceptibles de mejora aumentando la motivación del alumnado mediante nuevas metodologías docentes. Con este proyecto de innovación docente, hemos elaborado el material necesario para aplicar el método “flipped learning” o clase invertida en un bloque de temas de Biología Celular y en otro bloque de temas de Histología. Este tipo de metodología centrada en el alumno, permite que el estudiante procese y maneje la información suministrada de forma autónoma, antes de acudir a clase, a su ritmo, de manera que el tiempo de clase puede usarse de otras maneras, por ejemplo, para solucionar dudas, discutir a fondo los aspectos más complicados del tema, o para realizar tareas de aplicación de los conocimientos previamente aprendidos en casa. De esta manera se puede lograr un aprendizaje significativo alejado de la mera memorización de los contenidos expuestos, y en donde el alumno se sienta protagonista de su propio avance y capacitación teórica de la asignatura. Item Pyramidal cell axon initial segment in Alzheimer´s disease(Scientific Reports, 2022) Antón-Fernández, Alejandro; León-Espinosa, Gonzalo; DeFelipe, Javier; Muñoz Céspedes, AlbertoThe axon initial segment (AIS) is a region of the neuron that is critical for action potential generation as well as for the regulation of neural activity. This specialized structure—characterized by the expression of different types of ion channels as well as adhesion, scaffolding and cytoskeleton proteins—is subjected to morpho-functional plastic changes in length and position upon variations in neural activity or in pathological conditions. In the present study, using immunocytochemistry with the AT8 antibody (phospho-tau S202/T205) and 3D confocal microscopy reconstruction techniques in brain tissue from Alzheimer’s disease patients, we found that around half of the cortical pyramidal neurons with hyperphosphorylated tau showed changes in AIS length and position in comparison with AT8-negative neurons from the same cortical layers. We observed a wide variety of AIS alterations in neurons with hyperphosphorylated tau, although the most common changes were a proximal shift or a lengthening of the AISs. Similar results were found in neocortical tissue from non-demented cases with neurons containing hyperphosphorylated tau. These findings support the notion that the accumulation of phospho-tau is associated with structural alterations of the AIS that are likely to have an impact on normal neuronal activity, which might contribute to neuronal dysfunction in AD.Item Microanatomical study of pyramidal neurons in the contralesional somatosensory cortex after experimental ischemic stroke(Cerebral Cortex, 2022) Merino Serrais, Paula; Plaza Alonso, Sergio; Hellal, Farida; Valero Freitag, Susana; Kastanauskaite, Asta; Muñoz Céspedes, Alberto; Plesnila, Nikolaus; Felipe, Javier deAt present, many studies support the notion that after stroke, remote regions connected to the infarcted area are also affected and may contribute to functional outcome. In the present study, we have analyzed possible microanatomical alterations in pyramidal neurons from the contralesional hemisphere after induced stroke. We performed intracellular injections of Lucifer yellow in pyramidal neurons from layer III in the somatosensory cortex of the contralesional hemisphere in an ischemic stroke mouse model. A detailed 3-dimensional analysis of the neuronal complexity and morphological alterations of dendritic spines was then performed. Our results demonstrate that pyramidal neurons from layer III in the somatosensory cortex of the contralesional hemisphere show selective changes in their dendritic arbors, namely, less dendritic complexity of the apical dendritic arbor—but no changes in the basal dendritic arbor. In addition, we found differences in spine morphology in both apical and basal dendrites comparing the contralesional hemisphere with the lesional hemisphere. Our results show that pyramidal neurons of remote areas connected to the infarct zone exhibit a series of selective changes in neuronal complexity and morphological distribution of dendritic spines, supporting the hypothesis that remote regions connected to the peri-infarcted area are also affected after stroke.Item Estudio hodológico e inmunohistoquímico de las proyecciones ascendentes somatosensoriales en el sistema nervioso central de los anfibios(2002) Muñoz Céspedes, Alberto; Muñoz Martín, Margarita; Donkelaar, H. J. TenEn la presente memoria de tesis doctoral se ha realizado un estudio de las principales proyecciones espinales ascendentes y del lemnisco medial, en el sistema nervioso central de anuros y urodelos, mediante la utilización de técnicas de trazado neuronal, histoquimicas e inmunohistoquimicas. Dichas proyecciones se organizan en tres sistemas principales, al igual que en vertebrados amniotas, lo que sugiere un patrón común en la organización de las vías somatosensoriales en el cerebro de los vertebrados- Project number: PIMCD170/23-24
Item Microscopio virtual para las prácticas de organografía microscópica(2024) Muñoz Céspedes, Alberto; Leceta Martínez, Javier; Entrena Martínez, Ana; López Redondo, Jesús María; García-Ceca Hernández, José Javier; Lozano Rebollo, Daniel; Montero Herradón, Sara; Morona Arribas, Ruth; Muñoz Céspedes, Alberto Item Slow-wave activity in the S1HL cortex is contributed by different layer-specific field potential sources during development(Journal of Neuroscience, 2019) Ortuño, Tania; López-Madrona, Victor J.; Makarova, Julia; Tapia-Gonzalez, Silvia; Muñoz Céspedes, Alberto; DeFelipe, Javier; Herreras, ÓscarSpontaneous correlated activity in cortical columns is criticalfor postnatal circuit refinement.We used spatial discriminationtechniques to explore the late maturation of synaptic pathways through the laminar distribution of the field potential (FP) generators underlying spontaneous and evoked activities ofthe S1HL cortex in juvenile (P14 –P16) and adult anesthetized rats. Juveniles exhibit an intermittent FP pattern resembling Up/Down states in adults, but with much reduced power and different laminar distribution. Whereas FPs in active periods are dominated by a layer VI generator in juveniles, in adults a developing multipart generatortakes over, displaying current sinks in middle layers (III–V). The blockade of excitatory transmission in upper and middle layers of adults recovered the juvenile-like FP profiles. In additiontothe layer VI generator, a gamma-specific generator in supragranular layers wasthe same in both age groups.While searching for dynamical coupling among generators in juveniles we found significant cross-correlation in one-half of the tested pairs, whereas excessive coherence hindered their efficient separation in adults. Also, potentials evoked by tactile and electrical stimuli showed different short-latency dipoles between the two age groups, and the juveniles lacked the characteristic long latency UP state currents in middle layers. In addition, the mean firing rate of neurons was lower in juveniles. Thus, cortical FPs originate from different intracolumnar segments as they become active postnatally. We suggest that although some cortical segments are active early postnatally, a functional sensory-motor control relies on a delayed maturation and network integration of synaptic connections in middle layers.