Weakly encoded memories due to acute sleep restriction can be rescued after one night of recovery sleep

Sleep is thought to play a complementary role in human memory processing: sleep loss impairs the formation of new memories during the following awake period and, conversely, normal sleep promotes the strengthening of the already encoded memories. However, whether sleep can strengthen deteriorated memories caused by insufficient sleep remains unknown. Here, we showed that sleep restriction in a group of participants caused a reduction in the stability of EEG activity patterns across multiple encoding of the same event during awake, compared with a group of participants that got a full night's sleep. The decrease of neural stability patterns in the sleep-restricted group was associated with higher slow oscillation-spindle coupling during a subsequent night of normal sleep duration, thereby suggesting the instantiation of restorative neural mechanisms adaptively supporting cognition and memory. Importantly, upon awaking, the two groups of participants showed equivalent retrieval accuracy supported by subtle differences in the reinstatement of encoding-related activity: it was longer lasting in sleep-restricted individuals than in controls. In addition, sustained reinstatement over time was associated with increased coupling between spindles and slow oscillations. Taken together, these results suggest that the strength of prior encoding might be an important moderator of memory consolidation during sleep. Supporting this view, spindles nesting in the slow oscillation increased the probability of correct recognition only for weakly encoded memories. Current results demonstrate the benefit that a full night's sleep can induce to impaired memory traces caused by an inadequate amount of sleep

Stability of neural encoding moderates the contribution of sleep and repeated testing to memory consolidation

There is evidence suggesting that online consolidation during retrieval-mediated learning interacts with offline consolidation during subsequent sleep to transform memory. Here we investigate whether this interaction persists when retrieval-mediated learning follows post-training sleep and whether the direction of this interaction is conditioned by the quality of encoding resulting from manipulation of the amount of sleep on the previous night. The quality of encoding was determined by computing the degree of similarity between EEG-activity patterns across restudy of face pairs in two groups of young participants, one who slept the last 4 h of the pre-training night, and another who slept 8 h. The offline consolidation was assessed by computing the degree of coupling between slow oscillations (SOs) and spindles (SPs) during post-training sleep, while the online consolidation was evaluated by determining the degree of similarity between EEG-activity patterns recorded during the study phase and during repeated recognition of either the same face pair (i.e., specific similarity) or face pairs sharing sex and profession (i.e., categorical similarity) to evaluate differentiation and generalization, respectively. The study and recognition phases were separated by a night of normal sleep duration. Mixed-effects models revealed that the stability of neural encoding moderated the relationship between sleep- and retrieval-mediated consolidation processes over left frontal regions. For memories showing lower encoding stability, the enhanced SO-SP coupling was associated with increased reinstatement of category-specific encoding-related activity at the expense of content-specific activity, whilst the opposite occurred for memories showing greater encoding stability. Overall, these results suggest that offline consolidation during post-training sleep interacts with online consolidation during retrieval the next day to favor the reorganization of memory contents, by increasing specificity of stronger memories and generalization of the weaker ones.Laboratory of Functional Neuroscience, Universidad Pablo de Olavide, Seville 41013, SpainCIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, Spai

Zero-lag long-range synchronization via hippocampal dynamical relaying

2 páginas, 1 figura.-- Póster presentado al Nineteenth Annual Computational Neuroscience Meeting: CNS*2010 San Antonio, TX, USA; 24-30 July 2010.Peer reviewe

Linking Plasma Amyloid Beta and Neurofilament Light Chain to Intracortical Myelin Content in Cognitively Normal Older Adults

Evidence suggests that lightly myelinated cortical regions are vulnerable to aging and Alzheimer's disease (AD). However, it remains unknown whether plasma markers of amyloid and neurodegeneration are related to deficits in intracortical myelin content, and whether this relationship, in turn, is associated with altered patterns of resting-state functional connectivity (rs-FC). To shed light into these questions, plasma levels of amyloid-beta fragment 1-42 (A beta(1-42)) and neurofilament light chain (NfL) were measured using ultra-sensitive single-molecule array (Simoa) assays, and the intracortical myelin content was estimated with the ratio T1-weigthed/T2-weighted (T1w/T2w) in 133 cognitively normal older adults. We assessed: (i) whether plasma A beta(1-42) and/or NfL levels were associated with intracortical myelin content at different cortical depths and (ii) whether cortical regions showing myelin reductions also exhibited altered rs-FC patterns. Surface-based multiple regression analyses revealed that lower plasma A beta(1-42) and higher plasma NfL were associated with lower myelin content in temporo-parietal-occipital regions and the insular cortex, respectively. Whereas the association with A beta(1-42) decreased with depth, the NfL-myelin relationship was most evident in the innermost layer. Older individuals with higher plasma NfL levels also exhibited altered rs-FC between the insula and medial orbitofrontal cortex. Together, these findings establish a link between plasma markers of amyloid/neurodegeneration and intracortical myelin content in cognitively normal older adults, and support the role of plasma NfL in boosting aberrant FC patterns of the insular cortex, a central brain hub highly vulnerable to aging and neurodegeneration.This work was supported by the Spanish Ministry of Economy and Competitiveness (PID2020-119978RB-I00 to JLC and PID2020-118825GB-I00 to MA), CIBERNED (JLC, MA, CM, EC-Z, and FZ), Alzheimers Association (AARG-NFT-22-924702 to JLC), the Basque Government (IT1203-19; ELKARTEK KK-2020/00034 to EC-Z), the Research Program for a Long-Life Society of the Fundacion General CSIC (0551_PSL_6_E to JLC), the Junta de Andalucia (PY20_00858 to JLC), and the Andalucia-FEDER Program (UPO-1380913 to JLC)

Proyecto Coaster: un programa para generar prácticas interactivas basado en simulaciones matemáticas y aplicaciones multimedia

COASTER es un proyecto de la Unión Europea desarrollado por 6 universidades y 4 centros asociados de diferentes paises cuyo objetivo es realizar, demostrar y evaluar pedagógicamente la eficacia de un programa informático para generar simulaciones interactivas de prácticas de elevada calidad científica, pedagógica y técnica, basadas en experimentos reales de diferentes áreas de conocimiento como una alternativa al alto coste y a las limitaciones de los laboratorios experimentales para atender a una docencia práctica de calidad. COASTER es capaz de simular procesos biológicos y físicos e introduce aplicaciones multimedia para mejorar la comprensión de los contenidos por los estudiantes. Además, COASTER permite que un docente o un estudiante con conocimientos informáticos estándares pueda realizar experimentos basados en modelos matemáticos creados por los modelizadores, diseñados para recrear cualquier proceso biológico o físico siempre que se disponga de una descripción matemática del mismo

Effects of Nutrition on Cognitive Function in Adults with or without Cognitive Impairment: A Systematic Review of Randomized Controlled Clinical Trials

New dietary approaches for the prevention of cognitive impairment are being investigated. However, evidence from dietary interventions is mainly from food and nutrient supplement interventions, with inconsistent results and high heterogeneity between trials. We conducted a comprehensive systematic search of randomized controlled trials (RCTs) published in MEDLINE-PubMed, from January 2018 to July 2021, investigating the impact of dietary counseling, as well as food-based and dietary supplement interventions on cognitive function in adults with or without cognitive impairment. Based on the search strategy, 197 eligible publications were used for data abstraction. Finally, 61 articles were included in the analysis. There was reasonable evidence that dietary patterns, as well as food and dietary supplements improved cognitive domains or measures of brain integrity. The Mediterranean diet showed promising results, whereas the role of the DASH diet was not clear. Healthy food consumption improved cognitive function, although the quality of these studies was relatively low. The role of dietary supplements was mixed, with strong evidence of the benefits of polyphenols and combinations of nutrients, but with low evidence for PUFAs, vitamin D, specific protein, amino acids, and other types of supplements. Further well-designed RCTs are needed to guide the development of dietary approaches for the prevention of cognitive impairment

Spreadsheet for the simulation of artificial neural networks (ANNs)

La utilización de Redes de Neuronas Artificiales (RNA) en problemas de predicción de series de tiempo, clasificación y reconocimiento de patrones ha aumentado considerablemente en los últimos años. Programas informáticos de matemáticas de propósito general tales como MATLAB, MATHCAD y aplicaciones estadísticas como SPSS y S-PLUS incorporan herramientas que permiten implementar RNAs. A esta oferta de software hay que añadir programas específicos como NeuralWare, EasyNN o Neuron. Desde un punto de vista educativo, el acceso de los estudiantes a estos programas puede ser difícil dado que no están pensadas como herramientas didácticas. Por otro lado, las hojas de cálculo como Excel y Gnumeric incorporan utilidades que permiten implementar RNAs y son de fácil acceso para los estudiantes. El objetivo de este trabajo es proporcionar un pequeño tutorial sobre la utilización de Excel para implementar una RNA que nos permita ajustar los valores de una serie de tiempo correspondiente a actividad cerebral alfa y que permita al alumno entender el funcionamiento de estos dispositivos de cálculo.In recent years, the use of Artificial Neural Networks or ANNs has increased considerably to solve prediction problems in time series, classification and recognition of patterns. General-purpose mathematical programs such as MATLAB, MATHCAD and mathematical and statistical programs such as SPSS and S-PLUS incorporate tools that allow the implementation of ANNs. In addition to these, specific programs such as NeuralWare, EasyNN, or Neuron, complete the software offer using ANNs. From an educational point of view, an aspect that concerns the authors of this work, student access to these programs can be expensive or, in sorne case, unadvisable given the few possibilities they provide as didactic instruments. These programs are usually easy to use but do not facilitate the understanding of the technique used. On the other hand, spreadsheets like Excel or Gnumeric incorporate tools that allow all of the necessary calculations to implement an ANN. These programs are user-friendly to the point that they are used by university laboratories, as well as psychology, economic science, and engineering students, to mention a few. This paper provides a small tutorial on the use of a spreadsheet, specifically Excel, to implement an ANN to adjust the values of a time series corresponding to cerebral alpha activity

A survey of the professional weakening in relation with organizational factors in the nursing staff of the internal medicine deparment

Artículos originales[ES] El personal de enfermería es uno de los grupos profesionales más afectados por el Síndrome de burnout, debido a la gran cantidad de estresores diarios, inherentes a su profesión, que debe afrontar. El objetivo de este estudio fue analizar comparativamente el grado de estrés profesional y satisfacción laboral en un grupo de profesionales de enfermería de Medicina Interna en el año 1998 y 2005, e intentar analizar si existía relación con factores organizativos de la Institución. En ambos años se distribuyen 107 cuestionarios que incluían el Inventario de Burnout de Maslach (MBI) para medir la incidencia de Burnout y el Cuestionario de Satisfacción Laboral de Warr, Cook y Hall (1979). Se objetivó un descenso del grado de agotamiento emocional y un aumento del grado de realización personal. El grado de satisfacción laboral de los profesionales en ambos años objeto de estudio fue de moderadamente satisfecho. El hecho de disminuir la sobrecarga laboral y mejorar la seguridad en el puesto de trabajo podría influir positivamente en la reducción de la sobrecarga emocional. [EN] Nursing staff is one of the most affected professional groups the burnout syndrome due to the great quantity of everyday stressful factors which are attached to their profession which nurses have to face up to. The aim of this survey was to analyze comparatively the professional stress and labour self-satisfaction in a professional nursing staff of the internal medicine department between 1998 and 200 and to try to analyze if there was any relationship with organizational factors of the institution. 107 questionnaires were given out in both years the questionnaires included burnout inventory of Maslach to measure the incidence of burnout and the questionary of laboral self-satisfaction. The result of the survey was a falling-of the emotional exhaustion degree and an increase of the personal fulfilment degree. The degree of personal self-satisfaction of the nursing staff during these two years was moderately satisfied. The fact of decreasing the labour overload and the fact of improving the security in their job could positively have an influence on the lessening of the emotional overload.N