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Neuroinflammation after brain injury Traumatic brain injury affects millions of people every year and is a major cause of disability worldwide. Most of the maladaptive outcomes develop months or years later and are thought to be caused by secondary injuries that are indirect and long-term effects after the initial impact. Holden et al . found that secondary and chronic neuroinflammation and neurodegeneration are caused by the C1q molecule, a mediator of the complement pathway. C1q is responsible for chronic inflammation and secondary neuronal loss specifically in the cortico-thalamo-cortical circuit. Traumatic brain injury also leads to altered brain states that are caused by the C1q complement pathway. —PRS

Chronic pain patients frequently suffer from sleep disturbances. Improvement of sleep quality alleviates pain, but neurophysiological mechanisms underlying sleep disturbances require clarification to advance therapeutic strategies. Chronic pain causes high-frequency electrical activity in pain-processing cortical areas that could disrupt the normal process of low-frequency sleep rhythm generation. We found that the spared-nerve-injury (SNI) mouse model, mimicking human neuropathic pain, had preserved sleep-wake behavior. However, when we probed spontaneous arousability based on infraslow continuity-fragility dynamics of non-rapid-eye-movement sleep (NREMS), we found more numerous local cortical arousals accompanied by heart rate increases in hindlimb primary somatosensory, but not in prelimbic, cortices of SNI mice. Closed-loop mechanovibrational stimulation revealed higher sensory arousability in SNI. Sleep in chronic pain thus looked preserved in conventional measures but showed elevated spontaneous and evoked arousability. Our findings develop a novel moment-to-moment probing of NREMS fragility and propose that chronic pain-induced sleep complaints arise from perturbed arousability.

Objetivo: relacionar a atividade e a força muscular com a relação molar, o gênero e o rango de idade em crianças entre 7 e 12 anos com deglutição atípica. Materiais e Método: estudo analítico de casos e controles utilizou a amostragem probabilística. Examinaram-se 88 crianças em cada grupo. Realizou-se uma eletromiogra a de superfície (SEMG) dos músculos orbicular, mental e masseteres; se determinaram as forças compreensiva do orbicular dos lábios (FCO), contráctil do masseter direito (FCMD) e esquerdo (FCMI), extensora do músculo lingual (FEL) por mioescanogra a e a força de resistência do orbicular dos lábios (FRO) por balancear subcrítica. As comparações estatísticas se realizaram com a prova não paramétrica U de Mann-Withney (p< 0,05). Resultados: as amplitudes do registro SEMG dos músculos mental e masseteres foram significativamente maiores no grupo de deglutição atípica (da) com respeito aos controles. Ambos os gêneros apresentaram menor força contráctil dos masseteres e extensora do músculo lingual que os controles. No grupo de 7-9 anos, as crianças com da só diferem dos controles na força compressiva do orbicular e no grupo de 10-12 anos as crianças com da apresentam uma diminuição significativa de todas as forças musculares. Conclusão: os pacientes com da têm maior frequência na relação molar Classe II e Classe III em ambos os lados. Existem diferenças na atividade muscular e na força dos masseteres entre os sexos com e sem da, esta diferença acentuase ao aumentar a idade.

A pesar del amplio uso de la estimulación cerebral profunda para controlar patologías neurológicas y neuropsiquiátricas, su mecanismo de acción aún no es claramente conocido, y existen pocos estudios sistemáticos que relacionen la variación de parámetros de estimulación eléctrica (frecuencia, intensidad, duración del pulso) y la ejecución comportamental. La habénula es una estructura reguladora de respuestas emocionales diana en tratamientos para dolor crónico y depresión, pero la relación entre su estimulación crónica y el desempeño animal en pruebas conductuales no se ha establecido con claridad. Con el objetivo de evaluar el efecto emocional de la estimulación habenular crónica, en este estudio se utilizaron ratas Wistar que recibieron estimulación habenular a intensidad baja (10-80 pA) o alta (120-260 pA) y frecuencia baja (80-150 Hz) o alta (240380 Hz): BIBF-AIBF-BIAF-AIAF, durante 15 minutos a lo largo de tres días consecutivos. Al cuarto día, se hizo la evaluación en un laberinto elevado en cruz y en campo abierto. Los resultados indican un efecto de tipo ansiolítico en el tratamiento BIAF, en comparación con BIBF y AIBF (aumento del número de entradas, porcentaje de tiempo en brazos abiertos y de la distancia recorrida en ellos), efecto que no se explica por cambios en la locomotricidad (distancia recorrida en los brazos cerrados y la exploración en el campo abierto). Se concluye que el parámetro frecuencia posee mayor impacto sobre el efecto comportamental que la intensidad -lo que puede explicar algunos hallazgos paradójicos previos-, que los parámetros utilizados no poseen efecto ansiogénico, y que los efectos potencialmente ansiogénicos de la estimulación a baja frecuencia y el papel de los sistemas dopaminérgicos y serotoninérgicos encontrados deben ser estudiados en futuras investigaciones. Apesar do amplo uso da estimulação cerebral profunda para controlar patologias neurológicas e neuropsiquiátricas, seu mecanismo de ação ainda não é claramente conhecido e existem poucos estudos sistemáticos que relacionem a variação de parâmetros de estimulação elétrica (frequência, intensidade, duração do pulso) e a execução comportamental. A habênula é uma estrutura reguladora de respostas emocionais específicas em tratamentos para dor crònica e depressão, mas a relação entre sua estimulação crònica e o desempenho animal em testes comportamentais não foi claramente estabelecida. Com o objetivo de avaliar o efeito emocional da estimulação habenular crònica, neste estudo foram utilizados ratos Wistar que receberam estimulação habenular de intensidade baixa (10-80 pA) ou alta (120-260 pA) e frequência baixa (80-150 Hz) ou alta (240-380 Hz): BIBF-AIBF-BIAF-AIAF, durante 15 minutos ao longo de três dias consecutivos. No quarto dia, foi feita a avaliação em um labirinto em cruz elevado e em campo aberto. Os resultados indicam um efeito de tipo ansiolítico no tratamento BIAF, em comparação com BIBF e AIBF (aumento do número de entradas, porcentagem de tempo em braços abertos e da distância percorrida neles), efeito que não se explica por mudanças na locomotividade (distância percorrida nos braços fechados e a exploração no campo aberto). Conclui-se que o parâmetro "frequência" tem mais impacto sobre o efeito comportamental do que a "intensidade" - o que pode explicar algumas descobertas paradoxais prévias -, que os parâmetros utilizados não tenham efeito ansiogênico, e que os efeitos potencialmente ansiogênicos da estimulação de baixa frequência e o papel dos sistemas dopaminérgicos e serotoninérgicos encontrados devem ser estudados em pesquisas futuras. Deep brain stimulation is a widely-used approach to the treatment of neurologic and neuropsychiatric diseases. However, its mechanisms remain unclear. There are few systematic studies relating variations on electrical stimulation parameters (frequency, intensity, pulse duration) and behavioral outcome. The habenula relates to emotional behavior and is a main target for chronic pain and depression stimulation treatment. The relation between habenular electrical stimulation and performance in behavioral tests has not been clearly defined. In order to assess the emotional effects of chronic habenular electrical stimulation, Wistar male rats were unilaterally implanted with electrodes aimed to the lateral habenula and assigned to low (10-80 pA) or high (120-260 pA) intensity and low (80-150 Hz) or high (240-380 Hz) frequency conditions: BIBF-AIBF-BIAF-AIAF. They received electrical stimulation 15 minutes/day for three consecutive days and on the fourth day were tested in the elevated plus maze and the open field. The results of these study show that BIAF stimulation has a possible anxiolytic-like effect when compared to BIBF and AIBF (increase in the percentage of open-arms time, entries into the open-arms and total-distance-run in the open-arms). This is not due to any changes in locomotion (total-distance-run and open field exploration). It is concluded that frequency is more important than intensity for behavioral modification. This could explain some previous inconsistent results. The data also suggest that these parameters of stimulation have no anxiogenic effects. The role for dopaminergic and serotonergic systems must be subsequently evaluated as well as potential anxiogenic-like effects of low frequency stimulation.

In this paper, we address the problem of quantifying the commonly observed disorganization of the stereotyped wave form of the ERP associated with the P300 component in patients with Alzheimer's disease. To that extent, we propose two new measures of complexity which relate the spectral content of the signal with its temporal waveform: the spectral matching coefficient and the spectral matching entropy. We show by means of experiments that those measures effectively measure complexity and are related to the shape in an intuitive way. Those indexes are compared with commonly used measures of complexity when comparing AD patients against age-matched healthy controls. The results indicate that AD ERP signals are, indeed, more complex in the shape than that of controls, and this result is evidenced mainly by means of our new measures which have a better performance compared to similar ones. Finally, we try to explain this increase in complexity in light of the communication through coherence hypothesis framework, relating commonly found changes in the EEG with our own results.

Sleep stage classification is a highly addressed issue in polysomnography; It is considered a tedious and time-consuming task if done manually by the specialist; therefore, from the engineering point of view, several methods have been proposed to perform an automatic sleep stage classification. In this paper an unsupervised approach to automatic sleep stage clustering of EEG signals is proposed which uses spectral features related to signal power, coherences, asymmetries, and Wavelet coefficients; the set of features is classified using a clustering algorithm that optimizes a cost function of minimum sum of squares. Accuracy and kappa coefficients are comparable to those of the current literature as well as individual stage classification results. Methods and results are discussed in the light of the current literature, as well as the utility of the groups of features to differentiate the states of sleep. Finally, clustering techniques are recommended for implementation in support systems for sleep stage scoring.

Sleep is a growing area of research interest in medicine and neuroscience. Actually, one major concern is to find a correlation between several physiologic variables and sleep stages. There is a scientific agreement on the characteristics of the five stages of human sleep, based on EEG analysis. Nevertheless, manual stage classification is still the most widely used approach. This work proposes a new automatic sleep classification method based on unsupervised feature classification algorithms recently developed, and on EEG entropy measures. This scheme extracts entropy metrics from EEG records to obtain a feature vector. Then, these features are optimized in terms of relevance using the Q-α algorithm. Finally, the resulting set of features is entered into a clustering procedure to obtain a final segmentation of the sleep stages. The proposed method reached up to an average of 80% correctly classified stages for each patient separately while keeping the computational cost low., The authors would like to thank Universidad Autonoma de Manizales for financial support in the present work (Research project 328-038). This work has also been supported by the Spanish Ministry of Science and Innovation, research project TEC2009-14222.