66 research outputs found
Cognitive processing for step precision increases beta and gamma modulation during overground walking
Simultaneous Assessment of Spinal and Supraspinal Activity during Experienced Pain:An Alternative Approach using Information Theory
Variability and effect sizes of intracranial current source density estimations during pain: Systematic review, experimental findings, and future perspectives
Pain arises from the integration of sensory and cognitive processes in the brain, resulting in specific patterns of neural oscillations that can be characterized by measuring electrical brain activity. Current source density (CSD) estimation from low-resolution brain electromagnetic tomography (LORETA) and its standardized (sLORETA) and exact (eLORETA) variants, is a common approach to identify the spatiotemporal dynamics of the brain sources in physiological and pathological pain-related conditions. However, there is no consensus on the magnitude and variability of clinically or experimentally relevant effects for CSD estimations. Here, we systematically examined reports of sample size calculations and effect size estimations in all studies that included the keywords pain, and LORETA, sLORETA, or eLORETA in Scopus and PubMed. We also assessed the reliability of LORETA CSD estimations during non-painful and painful conditions to estimate hypothetical sample sizes for future experiments using CSD estimations. We found that none of the studies included in the systematic review reported sample size calculations, and less than 20% reported measures of central tendency and dispersion, which are necessary to estimate effect sizes. Based on these data and our experimental results, we determined that sample sizes commonly used in pain studies using CSD estimations are suitable to detect medium and large effect sizes in crossover designs and only large effects in parallel designs. These results provide a comprehensive summary of the effect sizes observed using LORETA in pain research, and this information can be used by clinicians and researchers to improve settings and designs of future pain studies.Fil: Völker, Juan Manuel. Aalborg University; DinamarcaFil: Arguissain, Federico Gabriel. Aalborg University; DinamarcaFil: Kæseler Andersen, Ole. Aalborg University; DinamarcaFil: Biurrun Manresa, José Alberto. Aalborg University; Dinamarca. Universidad Nacional de Entre Ríos. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática; Argentin
On the agreement between manual and automated methods for single-trial detection and estimation of features from event-related potentials
The agreement between humans and algorithms on whether an event-related potential (ERP) is present or not and the level of variation in the estimated values of its relevant features are largely unknown. Thus, the aim of this study was to determine the categorical and quantitative agreement between manual and automated methods for single-trial detection and estimation of ERP features. To this end, ERPs were elicited in sixteen healthy volunteers using electrical stimulation at graded intensities below and above the nociceptive withdrawal reflex threshold. Presence/absence of an ERP peak (categorical outcome) and its amplitude and latency (quantitative outcome) in each single-trial were evaluated independently by two human observers and two automated algorithms taken from existing literature. Categorical agreement was assessed using percentage positive and negative agreement and Cohen's κ, whereas quantitative agreement was evaluated using Bland-Altman analysis and the coefficient of variation. Typical values for the categorical agreement between manual and automated methods were derived, as well as reference values for the average and maximum differences that can be expected if one method is used instead of the others. Results showed that the human observers presented the highest categorical and quantitative agreement, and there were significantly large differences between detection and estimation of quantitative features among methods. In conclusion, substantial care should be taken in the selection of the detection/estimation approach, since factors like stimulation intensity and expected number of trials with/without response can play a significant role in the outcome of a study
Stimulus predictability moderates the withdrawal strategy in response to repetitive noxious stimulation in humans
Nociceptive withdrawal reflex (NWR) is a protective reaction to a noxious stimulus, resulting in withdrawal of the affected area and thus preventing potential tissue damage. This involuntary reaction consists of neural circuits, biomechanical strategies, and muscle activity that ensure an optimal withdrawal. Studies of lower limb NWR indicate that the amplitude of the NWR is highly modulated by extrinsic and intrinsic factors, such as stimulation site, intensity, frequency, and supraspinal activity, among others. Whether the predictability of the stimulus has an effect on the biomechanical strategies is still unclear. This study aimed to evaluate how the predictability of impending noxious stimuli modulate the NWR reaction in the lower limb. NWR was evoked on fifteen healthy participants by trains of electrical stimuli on the sole of the foot and was measured in one distal (tibialis anterior) and one proximal (biceps femoris) muscle. The predictability was manipulated by giving participants prior information about the onset of the stimulus trains and the number of delivered stimuli per train. Results showed that the predictability of the incoming stimuli differentially modulates the muscle activity involved in the NWR reaction. For the most unpredictable stimulus train, larger NWR at distal muscles were evoked. Furthermore, the stereotyped temporal summation profile to repeated stimulation was observed when the stimulus train was completely predictable, while it was disrupted in proximal muscles in unpredictable conditions. It is inferred that the reflex response is shaped by descending control, which dynamically tunes the activity of the muscles involved in the resulting reaction. NEW & NOTEWORTHY Innate defensive behaviors such as reflexes are found across all species, constituting preprogrammed responses to external threats that are not anticipated. Previous studies indicated that the excitability of the reflex arcs like spinal nociceptive withdrawal reflex (NWR) pathways in humans are modulated by several cognitive factors. This study assesses how the predictability of a threat affects the biomechanical pattern of the withdrawal response, showing that distal and proximal muscles are differentially modulated by descending control.Fil: Jure, Fabricio A.. Aalborg University; DinamarcaFil: Arguissain, Federico G.. Aalborg University; DinamarcaFil: Biurrun Manresa, José Alberto. Universidad Nacional de Entre Ríos. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Entre Ríos. Universidad Nacional de Entre Ríos. Centro de Investigaciones y Transferencia de Entre Ríos; Argentina. Aalborg University; DinamarcaFil: Graven Nielsen, Thomas. Aalborg University; DinamarcaFil: Andersen, Ole Kæseler. Aalborg University; Dinamarc
Debut con actividad leve del lupus eritematoso sistémico y su evolución
Objetivos: evaluar si los pacientes con lupus eritematoso sistémico (LES) al momento del diagnóstico con baja actividad de la enfermedad presentaron un curso más benigno de la enfermedad vs. aquellos que tuvieron actividad moderada/severa.
Materiales y métodos: estudio observacional, analítico, de cohorte retrospectiva. Se revisaron historias clínicas de pacientes con diagnóstico de LES según criterios del American College of Rheumatology (ACR 1982/1997), del Systemic Lupus International Collaborating Clinics (SLICC 2012) o del ACR/European League Against Rheumatism (EULAR 2019), con un seguimiento mínimo de un año, que acudieron a la Sección de Reumatología del Hospital Rivadavia de la Ciudad Autónoma de Buenos Aires.
Resultados: se incluyeron 100 pacientes con diagnóstico de LES, de los cuales el 44% presentaba actividad leve, mientras que el 56% tenía actividad moderada o severa al diagnóstico. Se observaron diferencias estadísticamente significativas entre ambos grupos en la cantidad de brotes a lo largo de la evolución de la enfermedad (mediana del grupo con actividad leve 0 [RIC 0-1] vs. mediana del grupo actividad moderada o severa 1 [RIC 1-2]; p<0,01). Se detectó un menor compromiso de órganos durante la evolución de la enfermedad en aquellos con actividad basal leve en comparación con actividad basal moderada/severa, con diferencias estadísticamente significativas en el
compromiso renal (15,91% vs. 55,36%; p<0,01).
Conclusiones: los pacientes con actividad basal baja tuvieron un curso más benigno de la enfermedad y una menor cantidad de brotes severos, en comparación con quienes presentaron actividad moderada/severa al inicio de la enfermedad
Respuesta a la fertilización nitrogenada del cultivar Memby Porá
La experiencia evaluó la respuesta de la variedad Memby Porá (variedad nueva lanzada en 2017 por el programa de mejoramiento de INTA) a la fertilización nitrogenada (Urea) en diferentes dosis y momentos de aplicación. El cultivar presentó una muy buena respuesta a la fertilización nitrogenada en altas dosis. El fraccionamiento de alta dosis de N incrementa la EUN y la EUR. El incremento en el rendimiento se explica principalmente por la mayor producción de panojas/m2, sin achicar el tamaño de la panoja.Fil: Pirchi, Héctor Javier. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Arguissain, Gustavo Gabriel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Gregori, Leonardo Agustín. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Crepy, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; Argentin
Ensayo de densidades del cultivar Memby Porá
Memby Porá presenta inicialmente hojas levemente inclinadas que le permiten captar, al inicio, una buena cantidad de radiación, disminuyendo las pérdidas en el suelo, para adquirir una posición de hojas erectas más tardíamente. Manifiesta altos niveles de eficiencia del uso de la radiación. La utilización de 60 a 80 kg de semilla de arroz de Memby Porá permiten lograr un alto rendimiento. La variedad presenta buena capacidad de macollaje, que le permite compensar los efectos diferenciales de densidad de siembra. El retorno en kilos de arroz por kilo de semilla invertida resulta superior en las densidades menores.Fil: Pirchi, Héctor Javier. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Arguissain, Gustavo Gabriel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Gregori, Leonardo Agustín. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Crepy, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Concepción del Uruguay; Argentin
Psychophysical and electrophysiological evidence for enhanced pain facilitation and unaltered pain inhibition in acute low back pain patients
The aim of this case-control study was to examine differences in neural correlates of pain facilitatory and inhibitory mechanisms between acute low back pain (LBP) patients and healthy individuals. Pressure pain tolerance, electrical pain detection thresholds, pain ratings to repetitive suprathreshold electrical stimulation (SES) and conditioned pain modulation (CPM) were assessed in 18 patients with acute LBP and 18 healthy control participants. Furthermore, event-related potentials (ERPs) in response to repetitive SES were obtained from high-density electroencephalography. Results showed that the LBP group presented lower pressure pain tolerance and higher pain ratings to SES compared with the control group. Both groups displayed effective CPM, with no differences in CPM magnitude between groups. Both groups presented similar reductions in ERP amplitudes during CPM, but ERP responses to repetitive SES were significantly larger in the LBP group. In conclusion, acute LBP patients presented enhanced pain facilitatory mechanisms, whereas no significant changes in pain inhibitory mechanisms were observed. These results provide new insight into the central mechanisms underlying acute LBP. Perspective: This article present evidence that acute LBP patients show enhanced pain facilitation and unaltered pain inhibition compared with pain-free volunteers. These results provide new insight into the central mechanisms underlying acute LBP.Fil: Vuilleumier, Pascal Henri. University of Bern; SuizaFil: Arguissain, Federico Gabriel. Aalborg University; DinamarcaFil: Biurrun Manresa, José Alberto. Aalborg University; Dinamarca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Entre Rios. Universidad Nacional de Entre Rios. Centro de Investigaciones y Transferencia de Entre Rios; ArgentinaFil: Neziri, Alban Ymer. University of Bern; Suiza. Regional Hospital of Langenthal; SuizaFil: Nirkko, Arto Christian. University of Bern; SuizaFil: Andersen, Ole Kæseler. Aalborg University; DinamarcaFil: Arendt-Nielsen, Lars. Aalborg University; DinamarcaFil: Curatolo, Michele. Aalborg University; Dinamarca. University of Washington; Estados Unido
El peso específico como un indicador de la calidad de semilla de arroz para la siembra
PosterEl ensayo se llevó a cabo durante la campaña 2010/11, en las instalaciones del campo experimental de arroz de la Estación Experimental Agropecuaria Concepción del Uruguay del INTA. Se realizó, en simultáneo, un trabajo de laboratorio y uno de campo.EEA Concepción del UruguayFil: Gregori, Leonardo Agustin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Pirchi, Hector Javier. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Arguissain, Gustavo Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Crepy, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; Argentin
- …