Efficiency characterization of a large neuronal network: a causal information approach

When inhibitory neurons constitute about 40% of neurons they could have an important antinociceptive role, as they would easily regulate the level of activity of other neurons. We consider a simple network of cortical spiking neurons with axonal conduction delays and spike timing dependent plasticity, representative of a cortical column or hypercolumn with large proportion of inhibitory neurons. Each neuron fires following a Hodgkin-Huxley like dynamics and it is interconnected randomly to other neurons. The network dynamics is investigated estimating Bandt and Pompe probability distribution function associated to the interspike intervals and taking different degrees of inter-connectivity across neurons. More specifically we take into account the fine temporal ``structures'' of the complex neuronal signals not just by using the probability distributions associated to the inter spike intervals, but instead considering much more subtle measures accounting for their causal information: the Shannon permutation entropy, Fisher permutation information and permutation statistical complexity. This allows us to investigate how the information of the system might saturate to a finite value as the degree of inter-connectivity across neurons grows, inferring the emergent dynamical properties of the system.Comment: 26 pages, 3 Figures; Physica A, in pres

Causal Shannon-Fisher Characterization of Motor/Imagery Movements in EEG

The electroencephalogram (EEG) is an electrophysiological monitoring method that allows us to glimpse the electrical activity of the brain. Neural oscillations patterns are perhaps the best salient feature of EEG as they are rhythmic activities of the brain that can be generated by interactions across neurons. Large-scale oscillations can be measured by EEG as the different oscillation patterns reflected within the different frequency bands, and can provide us with new insights into brain functions. In order to understand how information about the rhythmic activity of the brain during visuomotor/imagined cognitive tasks is encoded in the brain we precisely quantify the different features of the oscillatory patterns considering the Shannon-Fisher plane H × F. This allows us to distinguish the dynamics of rhythmic activities of the brain showing that the Beta band facilitate information transmission during visuomotor/imagined tasks.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico

Rhythmic activities of the brain: quantifying the high complexity of beta and gamma oscillations during visuomotor tasks

Electroencephalography (EEG) signals depict the electrical activity that take place at the surface of the brain, and provide an important tool for understanding a variety of cognitive processes. The EEG are the product of synchronized activity of the brain and variations in EEG oscillations patterns reflect the underlying changes in neuronal synchrony. Our aim is to characterize the complexity of the EEG rhythmic oscillations bands when the subjects performs a visuomotor or imagined cognitive tasks (imagined movement), providing a causal mapping of the dynamical rhythmic activities of the brain as a measure of attentional investment. We estimate the intrinsic correlational structure of the signals within the causality entropy-complexity plane H x C, where the enhanced complexity in the gamma 1, gamma 2 and beta 1 bands allow us to distinguish motor-visual memory tasks from control conditions. We identify the dynamics of the gamma 1, gamma 2 and beta 1 rhythmic oscillations within the zone of a chaotic dissipative behavior, while in contrast the beta 2 band shows a much higher level of entropy and a significant low level of complexity that corresponds to a non-invertible cubic map. Our findings enhance the importance of the gamma band during attention in perceptual feature binding during the visuomotor/imagery tasks.Fil: Baravalle, Román. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física de Líquidos y Sistemas Biológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física de Líquidos y Sistemas Biológicos; ArgentinaFil: Rosso, Osvaldo Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Montani, Fernando Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física de Líquidos y Sistemas Biológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física de Líquidos y Sistemas Biológicos; Argentin

Rhythmic activities of the brain: quantifying the high complexity of beta and gamma oscillations during visuomotor tasks

Electroencephalography (EEG) signals depict the electrical activity that take place at the surface of the brain, and provide an important tool for understanding a variety of cognitive processes. The EEG are the product of synchronized activity of the brain and variations in EEG oscillations patterns reflect the underlying changes in neuronal synchrony. Our aim is to characterize the complexity of the EEG rhythmic oscillations bands when the subjects performs a visuomotor or imagined cognitive tasks (imagined movement), providing a causal mapping of the dynamical rhythmic activities of the brain as a measure of attentional investment. We estimate the intrinsic correlational structure of the signals within the causality entropy-complexity plane H x C, where the enhanced complexity in the gamma 1, gamma 2 and beta 1 bands allow us to distinguish motor-visual memory tasks from control conditions. We identify the dynamics of the gamma 1, gamma 2 and beta 1 rhythmic oscillations within the zone of a chaotic dissipative behavior, while in contrast the beta 2 band shows a much higher level of entropy and a significant low level of complexity that corresponds to a non-invertible cubic map. Our findings enhance the importance of the gamma band during attention in perceptual feature binding during the visuomotor/imagery tasks.Instituto de Física de Líquidos y Sistemas Biológico

Clustering Weblogs on the Basis of a Topic Detection Method

In recent years we have seen a vast increase in the volume of information published on weblog sites and also the creation of new web technologies where people discuss actual events. The need for automatic tools to organize this massive amount of information is clear, but the particular characteristics of weblogs such as shortness and overlapping vocabulary make this task difficult. In this work, we present a novel methodology to cluster weblog posts according to the topics discussed therein. This methodology is based on a generative probabilistic model in conjunction with a Self-Term Expansion methodology. We present our results which demonstrate a considerable improvement over the baseline

Padrões de ocorrência da avifauna no refúgio de vida silvestre da Ilha dos Lobos, Rio Grande do Sul, Brasil

As áreas naturais protegidas são uma das principais ferramentas para a conservação da diversidade biológica. Contudo, muitas unidades de conservação (UCs) marinhas no Brasil carecem ainda de informações mais detalhadas sobre as comunidades biológicas existentes dentro de seus limites e regiões adjacentes. O levantamento da fauna de uma região auxilia com relevantes dados para a compreensão ecológica da área a ser preservada. Portanto, visando os aspectos descritos, foi realizado o levantamento da avifauna que ocorre no Refúgio de Vida Silvestre da Ilha dos Lobos (REVIS Ilha dos Lobos) (29°20’S; 52°06’W) localizada em frente ao município de Torres (RS), no sul do Brasil. O estudo tem como objetivo a realização do levantamento da avifauna no REVIS Ilha dos Lobos, bem como a análise dos padrões de ocorrência das espécies. Foram realizadas entre outubro de 2014 a março de 2019, 24 dias de observação e registro fotográfico, a partir de uma embarcação nas proximidades da ilha (< 100m), abrangendo todas as estações do ano. Na totalidade, foram registradas 27 espécies de aves pertencentes a 16 famílias, dentro dos limites do REVIS Ilha dos Lobos e em áreas do entorno. Deste total, 14 espécies foram observadas utilizando diretamente a Ilha, com abundância absoluta de 4882 indivíduos e média de 348,7 indivíduos/dia, (desvio padrão de 523,8), dentre as quais 67% são consideradas residentes e 33% visitantes do Hemisfério Norte (Piacentini, 2015). Thalasseus acuflavidus e Larus dominicanus foram as espécies que mais se destacaram em termos de abundância relativa e frequência de ocorrência. Além de T. acuflavidus, classificada como vulnerável (VU), outras duas espécies ameaçadas de extinção foram registradas: Calidris canutus (Em Perigo - EN) e Thalasseus maximus (EN) (RS, 2014). A ocorrência frequente de Haematopus palliatus ao longo de todas as estações do ano e a utilização da ilha como local de alimentação pela espécie também merece destaque em função da existência de áreas reprodutivas próximas à unidade de conservação. Os resultados do presente estudo demonstram a importância do REVIS Ilha dos Lobos como local de descanso e alimentação para diversas espécies de aves residentes e migratórias, além de espécies ameaçadas.Protected natural areas are one of the main tools for the conservation of biological diversity. However, many Marine Protected Areas (MPA) in Brazil still lack more detailed information on the biological communities existing within their limits and adjacent regions. The survey of fauna in a region helps with relevant data for the ecological understanding of the area to be preserved. Therefore, according to the described aspects, it was carried a survey of the avifauna that occurs at the Ilha dos Lobos Wildlife Refuge (REVIS Ilha dos Lobos) (29 ° 20'S; 52 ° 06'W) located in front of the municipality of Torres (RS) in southern Brazil. This study aims to describe avifauna whithin the REVIS Ilha dos Lobos MPA area, as well as their occurrence pattern. From October 2014 to March 2019, 24 days of observation and photographic records were conducted from a vessel close to the island (<100m), comprehending all the seasons of the year. In total, 27 bird species belonging to 16 families were registered within the limits of the REVIS Ilha dos Lobos. From this total, 14 species were observed using directly the Island, with absolute abundance of 4,882 individuals and an average of 348,7 individuals/day (standard deviation of 523,8), among which 67% are considered resident and 33% visitors from the Northern Hemisphere. Relative abundance and frequency of occurrence were mostly represented by Thalasseus acuflavidus and Larus dominicanus. Apart from T. acuflavidus, classified as vulnerable (VU), other two endangered species were registered: Calidris canutus (Endangered - EN) and Thalasseus maximus (EN). The high occurrence of Haematopus palliatus year-round and the use of the island by the species as a feeding site should also be highlighted due to the existence of breeding areas close to the MPA. The results of the present study demonstrate the importance of REVIS Ilha dos Lobos as a local of rest and feeding site for many species of birds, residents and migratory, and threatened species

Successful treatment of Stenotrophomonas maltophilia meningitis in a preterm baby boy: a case report

<p>Abstract</p> <p>Introduction</p> <p><it>Stenotrophomonas maltophilia</it> is an important cause of hospital acquired infection particularly among severely debilitated and immunosuppressed patients.</p> <p>Case presentation</p> <p>We report a case of <it>S. maltophilia</it> meningitis in a preterm baby boy after a neurosurgical procedure, successfully treated with trimethoprim-sulfamethoxazole and ciprofloxacin.</p> <p>Conclusion</p> <p>This organism should be considered as a potential cause of meningitis and trimethoprim-sulfamethoxazole and ciprofloxacin are a combination that is successful and safe for treating preterm infants.</p

Prototype/topic based Clustering Method for Weblogs

[EN] In the last 10 years, the information generated on weblog sites has increased exponentially, resulting in a clear need for intelligent approaches to analyse and organise this massive amount of information. In this work, we present a methodology to cluster weblog posts according to the topics discussed therein, which we derive by text analysis. We have called the methodology Prototype/Topic Based Clustering, an approach which is based on a generative probabilistic model in conjunction with a Self-Term Expansion methodology. The usage of the Self-Term Expansion methodology is to improve the representation of the data and the generative probabilistic model is employed to identify relevant topics discussed in the weblogs. We have modified the generative probabilistic model in order to exploit predefined initialisations of the model and have performed our experiments in narrow and wide domain subsets. The results of our approach have demonstrated a considerable improvement over the pre-defined baseline and alternative state of the art approaches, achieving an improvement of up to 20% in many cases. The experiments were performed on both narrow and wide domain datasets, with the latter showing better improvement. However in both cases, our results outperformed the baseline and state of the art algorithms.The work of the third author was carried out in the framework of the WIQ-EI IRSES project (Grant No. 269180) within the FP7 Marie Curie, the DIANA APPLICATIONS Finding Hidden Knowledge in Texts: Applications (TIN2012-38603-C02-01) project and the VLC/CAMPUS Microcluster on Multimodal Interaction in Intelligent Systems.Perez-Tellez, F.; Cardiff, J.; Rosso, P.; Pinto Avendaño, DE. (2016). Prototype/topic based Clustering Method for Weblogs. Intelligent Data Analysis. 20(1):47-65. https://doi.org/10.3233/IDA-150793S476520