Modulatory effects mediated by metabotropic glutamate receptor 5 on lateral geniculate nucleus relay cells

[Abstract] Glutamate is thought to be the excitatory neurotransmitter in the lateral geniculate nucleus (LGN) of the cat, mediating visual transmission from the retina via ionotropic receptors of both d,l-α-amino-3-hydroxy-5-α-methyl-4-isoxazolepropionate and N-methyl-d-aspartate subtypes. Moreover, glutamate also exerts an important modulatory influence on LGN cells, where metabotropic glutamate receptors (mGluRs) seem to play a crucial role. Here we show in anesthetized adult cats that iontophoretic application of the specific mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) produced two, distinctly different, effects on LGN neurons. Visual responses to flashing spots and drifting gratings were attenuated (decreased by an average of 59%) in 13 of 23 of the cells but augmented (increased by an average of 60%) in 10 of 23 of the cells. Further, in each case when the specific mGluR5 agonist (R,S)-2-chloro-5-hydroxyphenylglycine was applied, the effects obtained were the opposite to those of MPEP. Data obtained in a second group of experiments to determine a possible interaction between mGluR5 blockade by MPEP and glutamate ionotropic receptors show that, in the majority of neurons (11 of 15, 73%), the MPEP-mediated effects seem to be independent of N-methyl-d-aspartate and d,l-α-amino-3-hydroxy-5-α-methyl-4-isoxazolepropionate receptor activity. Our results demonstrate a physiological role for mGluR5 in controlling retinal input and show, in vivo, a more intricate scenario than previously suggested, highlighting the complexity of metabotropic receptor interactions with excitatory and inhibitory elements in the thalamus.Ministerio de Ciencia y Tecnología; BFI2002-320

Procesamiento visual temprano durante la rivalidad binocular

[Resumen] La tesis presentada se centro en estudiar los correlatos neurales de la conciencia visual empleando para ello tecnicas no invasivas electricas (potenciales evocados visuales, VEPs) y opticas durante la rivalidad binocular. En los experimentos de rivalidad binocular dos imágenes diferentes se presentan a cada ojo, causando dos interpretaciones perceptuales alternativas. Debido a que los cambios en la percepcion ocurren a pesar de que el estimulo visual es constante, el paradigma de rivalidad binocular ofrece una excelente oportunidad para estudiar los correlatos neurales de la conciencia visual. Los resultados con los VEPs revelaron un potencial, que se extiende desde los 100 hasta los 300 ms, relacionado con el estado de rivalidad. A este potencial se denomino RRP (Rivaly-Related Potencial, RRP). El temprano comienzo del RRP, distribucion y polaridad sugirio que este potencial podria originarse en el cortex visual primario o V1. El origen del RRP se investigo empleando una tecnica optica conocida con el nombre de EROS (Event-Related Optical Signal). En esta tecnica se injecta luz cerca del infrarrojo (NIR) en el craneo y se miden los cambios en la dispersion de la luz producidos por la estimulacion sensorial. La ventaja de esta tecnica optica es que posee una mayor resolucion espacial que la señal de EEG(electroencefalografia). Con estimulos foveales se encontro que la actividad en V1 no varia con el estado perceptual del sujeto

Synergistic effects of applying static magnetic fields and diazepam to improve EEG abnormalities in the pilocarpine epilepsy rat model

[Abstract] The lithium-pilocarpine rat model is a well-known model of temporal epilepsy. Recently we found that transcranial static magnetic stimulation (tSMS) delay and reduce the signs of EEG in this model. We aim to test the effect of combining the therapeutic action of tSMS and diazepam, a drug used to treat status epilepticus. We induce epilepsy in 12 Sprague-Dawley rats. Animals were classified as "magnet" when a magnetic neodymium cylinder was placed over the skull or "control" when a stainless-steel replica was used. Diazepam was injected 60-min after the second doses of pilocarpine injection. We found a reduction in the number of spikes/minute for magnet condition compared with sham condition, reaching significance at 60 min after diazepam injection. The Root-Mean-Square shown a significant reduction in magnet animals compared with those receiving diazepam (Tukey's-test 30 and 60 min after diazepam injection, p < 0.01; 40 and 50 min after diazepam injection, p < 0.05). Furthermore, the power spectrum analysis shown a reduction in delta, theta, alpha and beta bands, on the diazepam + magnet animals compared to the diazepam + sham group. Analysis of high-frequency oscillations revealed an increased in the ripples due to pilocarpine being reduced by diazepam. Our results demonstrate that application of tSMS previously to diazepam potentiates the effect of the drug by reducing the electroencephalographic pattern associated with epileptiform discharges. We suggest a new synergistic cooperation between pharmacology and neuromodulation as a future treatment for epilepsy.Instituto de Salud Carlos III; PI21/00151Xunta de Galicia; ED431C 2022/0

Evaluación de la asignatura de Fisiología de Sistemas a través del Cuestionario de Incidencias Críticas

[Resumen] El Espacio Europeo de Educación Superior (EEES) es el marco de referencia actual sobre el que trabajan las diferentes universidades que pertenecen a la Unión Europea. Dentro de este escenario se pone a disposición del alumnado una metodología más participativa, centrada en el desarrollo de habilidades y conocimiento. En este contexto se vuelve necesario que los profesores realicemos una evaluación crítica sobre nuestra actual actividad docente. Para conseguirlo es necesario conocer la opinión de nuestros estudiantes. Por ello, al finalizar el segundo cuatrimestre del curso 2017-2018, dentro del Grado en Podología (Facultad de Enfermería y Podología) y para la asignatura de Fisiología de Sistemas, hemos llevado a cabo un estudio piloto empleando el Cuestionario de Incidencias Críticas (Bará y Valero, 2003). En el cuestionario, compuesto de dos preguntas abiertas, se solicita al estudiantado que describa la incidencia crítica más positiva y más negativa que ha ocurrido durante el transcurso de la materia. Una vez obtenidos y analizados los resultados por la responsable de la materia, se compartieron las respuestas con el alumnado con el objetivo de hacerles saber que sus comentarios se tienen en cuenta, así como para tomar medidas oportunas de cara a resolver las incidencias más negativas. Como conclusión podemos decir que la aplicación del Cuestionario de Incidencias Críticas ha servido para conocer la opinión que nuestros estudiantes tienen sobre la materia, así como para detectar los puntos de mejora que se deben aplicar a la misma, lo que sin duda influirá en la calidad de nuestra docenci

Psychophysiological studies of unattended information processing

[Abstract] The article describes the general methods and some of the results obtained in the Psychophysiology Laboratory of the University of La Coruña. The paper covers our research on the Simon effect and accessory effect, although it is not a review of the literature. The research strategy we followed is built around the use of lateralized motor potentials recorded from scalp. These measures allow observing the way responses are selected and when they are selected, providing an invaluable tool to study response interference and to split reaction time into two halves. The research on the Simon effect concludes that interference during response selection is critical in the Simon effect but it is dubious whether this process should be considered as automatic and stimulus-driven, as is widely accepted. The experiments with the accessory effect indicate that facilitation is produced before response selection is over, which ends a long controversy about the locus of the accessory effect.[Resumen] El artículo describe el método y algunos de los resultados obtenidos en el laboratorio de Psicofisiología de la Universidad de La Coruña. El trabajo abarca nuestra investigación sobre el efecto Simon y sobre el efecto accesorio, aunque no es una revisión del corpus teórico. La estrategia de investigación seguida en estos experimentos se basa en la utilización de potenciales motores lateralizados que se registran sobre cuero cabelludo. Estas medidas permiten observar cómo y cuándo se seleccionan las respuestas, proporcionando una valiosísima herramienta para estudiar la interferencia de respuesta y para partir el tiempo de reacción en dos mitades. Nuestra investigación sobre el efecto Simon concluye que la interferencia durante la selección de respuesta es crucial en el efecto Simon, pero no está tan claro si este proceso debe considerarse automático y guiado por el estímulo, como defienden la mayoría de las teorías actuales. Los experimentos con el efecto accesorio indican que la facilitación se produce antes de que termine la selección de respuesta, lo que acaba con una larga controversia acerca del locus del efecto accesorio

Stimulus-response compatibility between stimulated eye and response location: implications for attentional accounts of the Simon effect

[Abstract] One influential theory of the Simon effect, the attention-shift hypothesis, states that attention movements are the origin of spatial stimulus codes. According to this hypothesis, stimulus-response compatibility effects should be absent when attention shifts are prevented. To test this prediction, we used monocular patches of color that required left or right key-press responses. About half of the subjects could discriminate which eye was stimulated (in a subsequent task), and showed strong spatial compatibility effects between the stimulated eye and the response location. The other half of the subjects could not make a utrocular discrimination (i.e., they could not judge which eye had received monocular stimulation), but the pattern of results was the same: the fastest reaction times were observed when the stimulated eye corresponded spatially to the required response (i.e., a Simon effect). Since the subjects presumably did not move their attention (from the subject's point of view, the stimuli were presented centrally), our results indicate that spatial codes can be produced in the absence of attention shifts. These results also show that utrocular discrimination can be assessed via indirect measures that are much more sensitive than explicit measures.Ministerio de Cultura (España); PR2002–007

Perceived physical self-concept profiles: intention to be physically active and emotional regulation

[Abstract] The objectives of the study were to identify physical self-concept profiles and examine their role in the intention to be physically active and emotional regulation. A sample of 606 physical activity practitioners (Mage= 34.19, SD= 13.05), completed a series of self-report measures that evaluated physical selfconcept, the intention to be physically active, and emotional regulation. Cluster analyzes revealed three profiles of physical self-concept. Profile b with relatively high physical self-concept experienced significant differences in intention to be physically active, self-blame, and positive reappraisal. Profile a with low physical self-concept showed significant differences in acceptance, rumination, and catastrophizing. Profile c with a very low physical self-concept revealed significant differences in blaming others. In conclusion, profile b with relatively high physical self-concept and with optimal scores in condition, attractiveness and strength is associated with a higher intention to be physically active and the use of functional emotional regulation strategies.[Resumen] Los objetivos del estudio fueron identificar perfiles de autoconcepto físico y examinar su rol sobre la intención de ser físicamente activo y la regulación emocional. Una muestra de 606 practicantes de actividad física (Medad= 34,19; DT= 13,05) completó una serie de medidas de autoinforme que evaluaban el autoconcepto físico, la intención de ser físicamente activo y la regulación emocional. Los análisis de conglomerados revelaron tres perfiles de autoconcepto físico. El perfil b con autoconcepto físico relativamente alto experimentó diferencias significativas en la intención de ser físicamente activo, autoculpa y reevaluación positiva. El perfil a con autoconcepto físico bajo mostró diferencias significativas en aceptación, rumiación y catastrofización. El perfil c con autoconcepto físico muy bajo reveló diferencias significativas en culpar a los demás. Como conclusión, el perfil b con autoconcepto físico relativamente alto está asociado con la mayor intencionalidad de ser físicamente activo y el uso de estrategias de regulación emocional funcionales

Análise dos resultados obtidos nos procesos de avaliación da materia de Fisioloxía Humana durante a COVID-19

[Resumo] Neste traballo presentamos unha análise dos resultados obtidos nos exames finais da materia de Fisioloxía Humana durante a COVID-19, materia impartida no grao de podoloxía da UDC. Estes resultados comparáronse cos obtidos en cursos anteriores en exames levados a cabo de xeito presencial. En todos os casos os resultados proceden de exames tipo test de resposta única. Para levar a cabo esta análise tivéronse en conta os cursos académicos 2017/2018 e 2018/2019, no que analizamos os resultados de 165 exames realizados de xeito presencial e comparámolos cos resultados de 46 exames realizados virtualmente no curso académico 2019/2020. Non se observaron diferencias na cualificación media obtida en ambas modalidades de exames. Non obstante, nos exames virtuais diminúe lixeiramente a porcentaxe de alumnos non presentados e a porcentaxe de suspensos e tres veces máis baixa, sen embargo, tamén diminúe o número de estudantes que obteñen sobresaínte. En base a estes resultados podemos concluír que os exames tipo test virtuais aumentan o número de estudantes que supera a materia, pero non así a nota global da mesma.[Abstract] In this work we present an analysis of the results obtained in the final exams of the Human Physiology subject during COVID-19, a subject taught in the podiatry degree at the UDC. These results were compared with those obtained in previous academic years in exams carried out face-to-face. In all cases, the results come from single-response multiple-choice tests. To carry out this analysis, the academic years 2017/2018 and 2018/2019 were taken into account, in which we analysed the results of 165 exams taken face-to-face and compared them with the results of 46 exams conducted online in the academic year 2019/2020. No differences were observed in the average qualification obtained in both exam modalities. However, in virtual exams the percentage of students not presented decreases slightly and the percentage of failures is three times lower, however, the number of students who obtain high marks also decreases. Based on these results, we can conclude that online exams increase the number of students who pass the subject, but not the overall mark.http://hdl.handle.net/2183/2879

Adaptación da docencia de Fisioloxía Humana ante a pandemia da Covid-19

[Resumo] A pandemia causada polo SARS-CoV-2 provocou un cambio no modelo educativo, principalmente polas medidas de seguridade adoptadas. O obxectivo do presente traballo é analizar os resultados da aprendizaxe a distancia na materia de Fisioloxía do grao en Podoloxía e Enfermería, pertencentes á UDC.[Abstract] The pandemic caused by SARS-CoV-2 has caused a change in the educational model, mainly due to the security measures adopted. The objective of this work is to analyze the results of distance learning in the Physiology subject of the degree in Podiatry and Nursing, belonging to the UDC.http://hdl.handle.net/2183/2879

Different Sources of Nitric Oxide Mediate Neurovascular Coupling in the Lateral Geniculate Nucleus of the Cat

Understanding the link between neuronal responses (NRs) and metabolic signals is fundamental to our knowledge of brain function and it is a milestone in our efforts to interpret data from modern non invasive optical techniques such as fMRI, which are based on the close coupling between metabolic demand of active neurons and local changes in blood flow. The challenge is to unravel the link. Here we show, using spectrophotometry to record oxyhaemoglobin and methemoglobin (surrogate markers of cerebral flow and nitric oxide levels respectively) together with extracellular neuronal recordings in vivo and applying a multiple polynomial regression model, that the markers are able to predict up about 80% of variability in NR. Furthermore, we show that the coupling between blood flow and neuronal activity is heavily influenced by nitric oxide (NO). While NRs show the typical saturating response, blood flow shows a linear behaviour during contrast-response curves, with nitric oxide from different sources acting differently for low and high intensity