Seizure states identification in experimental epilepsy using gabor atom analysis

Background: Epileptic seizures evolve through several states, and in the process the brain signals may change dramatically. Signals from different states share similar features, making it difficult to distinguish them from a time series; the goal of this work is to build a classifier capable of identifying seizure statesbased on time frequency features taken from short signal segments.Methods: There are different amounts of frequency components within each Time Frequency window foreach seizure state, referred to as the Gabor atom density. Taking short signal segments from the differentstates and decomposing them into their atoms, the present paper suggests that is possible to identifyeach seizure state based on the Gabor atom density. The brain signals used in this work were taken for a database of intracranial recorded seizures from the Kindling model.Results: The findings suggest that short signal segments have enough information to be used to derivea classifier able to identify the seizure states with reasonable confidence, particularly when used withseizures from the same subject. Achieving average sensitivity values between 0.82 and 0.97, and areaunder the curve values between 0.5 and 0.9. Conclusions: The experimental results suggest that seizure states can be revealed by the Gabor atom density; and combining this feature with the epoch s energy produces an improved classifier. These results are comparable with the recently published on state identification. In addition, considering that the order of seizure states is unlikely to change, these results are promising for automatic seizure state classification.Thanks are extended to the Hospital Universitario de Valencia, for sharing their signal database and to Francisco Sancho for his support. Finally, thanks are given to Dr. Luis N. Coria for his support and the proofreading support. Partial funding for this work was provided by CONACYT Basic Science Research Project No. 178323, DGEST (Mexico) Research Projects No. 5149.13-P, 5414.14-P and TIJ-ING-2012-110, and IRSES project ACoBSEC financed by the European Commission.Sotelo Orozco, A.; Guijarro Estelles, ED.; Trujillo, L. (2015). Seizure states identification in experimental epilepsy using gabor atom analysis. Journal of Neuroscience Methods. 241:121-131. https://doi.org/10.1016/j.jneumeth.2014.12.001S12113124

Studies of properties of “Pain Networks” as predictors of targets of stimulation for treatment of pain

Two decades of functional imaging studies have demonstrated pain-related activations of primary somatic sensory cortex (S1), parasylvian cortical structures (PS), and medial frontal cortical structures (MF), which are often described as modules in a “pain network.” The directionality and temporal dynamics of interactions between and within the cortical and thalamic modules are uncertain. We now describe our studies of these interactions based upon recordings of local field potentials (LFPs) carried out in an epilepsy monitoring unit over the one week period between the implantation and removal of cortical electrodes during the surgical treatment of epilepsy. These recordings have unprecedented clarity and resolution for the study of LFPs related to the experimental pain induced by cutaneous application of a Thulium YAG laser. We also used attention and distraction as behavioral probes to study the psychophysics and neuroscience of the cortical “pain network.” In these studies, electrical activation of cortex was measured by event-related desynchronization (ERD), over SI, PS, and MF modules, and was more widespread and intense while attending to painful stimuli than while being distracted from them. This difference was particularly prominent over PS. In addition, greater perceived intensity of painful stimuli was associated with more widespread and intense ERD. Connectivity of these modules was then examined for dynamic causal interactions within and between modules by using the Granger causality (GRC). Prior to the laser stimuli, a task involving attention to the painful stimulus consistently increased the number of event-related causality (ERC) pairs both within the SI cortex, and from SI upon PS (SI > PS). After the laser stimulus, attention to a painful stimulus increased the number of ERC pairs from SI > PS, and SI > MF, and within the SI module. LFP at some electrode sites (critical sites) exerted ERC influences upon signals at multiple widespread electrodes, both in other cortical modules and within the module where the critical site was located. In summary, critical sites and SI modules may bind the cortical modules together into a “pain network,” and disruption of that network by stimulation might be used to treat pain. These results in humans may be uniquely useful to design and optimize anatomically based pain therapies, such as stimulation of the S1 or critical sites through transcutaneous magnetic fields or implanted electrodes

Ictal propagation of high frequency activity is recapitulated in interictal recordings: effective connectivity of epileptogenic networks recorded with intracranial EEG

Seizures are increasingly understood to arise from epileptogenic networks across which ictal activity is propagated and sustained. In patients undergoing invasive monitoring for epilepsy surgery, high frequency oscillations have been observed within the seizure onset zone during both ictal and interictal intervals. We hypothesized that the patterns by which high frequency activity is propagated would help elucidate epileptogenic networks and thereby identify network nodes relevant for surgical planning. Intracranial EEG recordings were analyzed with a multivariate autoregressive modeling technique (short-time direct directed transfer function--SdDTF), based on the concept of Granger causality, to estimate the directionality and intensity of propagation of high frequency activity (70-175 Hz) during ictal and interictal recordings. These analyses revealed prominent divergence and convergence of high frequency activity propagation at sites identified by epileptologists as part of the ictal onset zone. In contrast, relatively little propagation of this activity was observed among the other analyzed sites. This pattern was observed in both subdural and depth electrode recordings of patients with focal ictal onset, but not in patients with a widely distributed ictal onset. In patients with focal ictal onsets, the patterns of propagation recorded during pre-ictal (up to 5 min immediately preceding ictal onset) and interictal (more than 24h before and after seizures) intervals were very similar to those recorded during seizures. The ability to characterize epileptogenic networks from interictal recordings could have important clinical implications for epilepsy surgery planning by reducing the need for prolonged invasive monitoring to record spontaneous seizures

Environmental and economic assessment of the formic acid electrochemical manufacture using carbon dioxide: Influence of the electrode lifetime

This paper focuses on the study of the environmental and economic feasibility of the formic acid (FA) synthesis by means of electrochemical reduction (ER) of carbon dioxide (CO2) with special emphasis on the cathode lifetime. The study has used a Life Cycle Assessment (LCA) approach in order to obtain the environmental indicators as Global Warming Potential (GWP) and Abiotic Depletion (ADP) (both elements and fossil resources ADPs). The values of the indicators obtained in the assessment were representative of the Carbon Footprint (CF) and resource savings of this fabrication process. The commercial/conventional process for FA production was used as benchmark. The novelty of the study is the incorporation into the Life Cycle Inventory (LCI) of those materials and chemicals that are used in the fabrication of an ER cell, and in particular in the cathode. Hence, the lifetime of the cathode was used as a main parameter. The results obtained for a baseline case demonstrated that cathode lifetimes over 210 h would be enough to neglect the influence of the cathode fabrication from an environmental perspective. A first approach to the utility costs of CO2 ER process was also proposed in the study. Cost of utilities ranged between 0.16 € kg and 1.40 € kg-1 of FA in an ER process compared with 0.21 € kg-1 and 0.43 € kg-1 of FA in the conventional process depending on the market prices. This study demonstrated that the ER-based process could be competitive under future conditions if a reasonable electrocatalytic performance (in terms of cell voltage, current density, and faradaic efficiency) is achieved within a reasonable medium or long-term horizon. The results obtained aim to provide useful insights for decision-makers on the future developments within a decarbonized chemical industry.Authors thank to Spanish Ministry of Economy and Competitiveness (MINECO) for the financial support through the project CTQ2016-76231-C2-1-R. We would like also to thank MINECO for providing Marta Rumayor with a Juan de la Cierva postdoctoral contract (FJCI-2015-23658)

Controversies in epilepsy: Debates held during the Fourth International Workshop on Seizure Prediction

Debates on six controversial topics were held during the Fourth International Workshop on Seizure Prediction (IWSP4) convened in Kansas City, KS, USA, July 4–7, 2009. The topics were (1) Ictogenesis: Focus versus Network? (2) Spikes and Seizures: Step-relatives or Siblings? (3) Ictogenesis: A Result of Hyposynchrony? (4) Can Focal Seizures Be Caused by Excessive Inhibition? (5) Do High-Frequency Oscillations Provide Relevant Independent Information? (6) Phase Synchronization: Is It Worthwhile as Measured? This article, written by the IWSP4 organizing committee and the debaters, summarizes the arguments presented during the debates

On the methodological unification in electroencephalography

BACKGROUND: This paper presents results of a pursuit of a repeatable and objective methodology of analysis of the electroencephalographic (EEG) time series. METHODS: Adaptive time-frequency approximations of EEG are discussed in the light of the available experimental and theoretical evidence, and applicability in various experimental and clinical setups. RESULTS: Four lemmas and three conjectures support the following conclusion. CONCLUSION: Adaptive time-frequency approximations of signals unify most of the univariate computational approaches to EEG analysis, and offer compatibility with its traditional (visual) analysis, used in clinical applications

Intrinsic antibacterial activity of nanoparticles made of β-cyclodextrins potentiates their effect as drug nanocarriers against tuberculosis

Multi-drug-resistant tuberculosis (TB) is a major public health problem, concerning about half a million cases each year. Patients hardly adhere to the current strict treatment consisting of more than 10 000 tablets over a 2-year period. There is a clear need for efficient and better formulated medications. We have previously shown that nanoparticles made of cross-linked poly-β-cyclodextrins (pβCD) are efficient vehicles for pulmonary delivery of powerful combinations of anti-TB drugs. Here, we report that in addition to being efficient drug carriers, pβCD nanoparticles are endowed with intrinsic antibacterial properties. Empty pβCD nanoparticles are able to impair Mycobacterium tuberculosis (Mtb) establishment after pulmonary administration in mice. pβCD hamper colonization of macrophages by Mtb by interfering with lipid rafts, without inducing toxicity. Moreover, pβCD provoke macrophage apoptosis, leading to depletion of infected cells, thus creating a lung microenvironment detrimental to Mtb persistence. Taken together, our results suggest that pβCD nanoparticles loaded or not with antibiotics have an antibacterial action on their own and could be used as a carrier in drug regimen formulations effective against TB.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The carbon footprint of power-to-synthetic natural gas by photovoltaic solar powered electrochemical reduction of CO2

The search for more sustainable production and consumption patterns entails the integration of emerging edge-cutting technologies. Holistic studies are needed in order to accurately evaluate properly the environmental competitiveness of the suggested solutions. Among those alternatives, it has been suggested the utilisation of CO2 for the production of synthetic natural gas, the so-called Power-to-Gas (PtG) technology. In this work, we use the PtG technology to analyse the environmental rationality in terms of the carbon footprint (CF) of a Photovoltaic (PV) solar powered Electrochemical Reduction (ER) process for the utilisation of CO2 as carbon source for the production of CH4. This synthetic natural gas is ready to be injected into the transmission and distribution network. The raw materials for the process are a source of CO2 (mixed with different ratios of N2), H2O and electricity from PV solar. The separated products are CH4, C2H4, H2/CO, O2 and HCOOH. The reaction, separation/purification and compression stages needed to deliver commercially distributable products are included. Mass and energy balances were used to create a black-box model. The input to the model is the faradaic efficiency and cathodic potential of the best cathodesperforming at lab-scale (over 60% faradaic efficiency towards CH4). It was assumed that cathodes were long-lasting. The output of the model is the distribution of products (related to 1 kg of pure CH4) and the energy consumption at each of the aforementioned stages. The overall CF is then calculated as a function of the CF PV solar reference and the total energy consumption. The effect on the distribution of each stage to the total energy consumption of both the purity of the CO2 stream and the conversion of CO2 in the reactor was analysed. The results show that the principal contributor to the total energy consumption is the ER of CH4 across all CO2concentrations and conversions. When a CO2 conversion of 50% is chosen together with an inlet stream with a N2:CO2 ratio of 24, the electricity consumption of the process is between 2.6 and 6.2 times the minimum obtained for a reference ER reactor including the separation and compression of gaseous products (18.5 kWh kg−1 of CH4). The use of PV solar energywith low CF (14⋅10−3 kg kWh−1) allows the current lab-scale performers to even the CF associated with the average world production of natural gas when the valorisation of C2H4 is included (∼1.0 kg kg−1 of CH4).Authors gratefully acknowledge the funding provided by the State Research Agency, Ministry of Science, Innovation, and Universities (Spain) through the project CTQ2016-76231-C2-1-R

Impact of pe_pgrs33 gene polymorphisms on mycobacterium tuberculosis infection and pathogenesis

PE_PGRS33 is a surface-exposed protein of Mycobacterium tuberculosis (Mtb) which exerts its role in macrophages entry and immunomodulation. In this study, we aimed to investigate the polymorphisms in the pe_pgrs33 gene of Mtb clinical isolates and evaluate their impact on protein functions. We sequenced pe_pgrs33 in a collection of 135 clinical strains, genotyped by 15-loci MIRU-VNTR and spoligotyping and belonging to the Mtb complex (MTBC). Overall, an association between pe_pgrs33 alleles and MTBC genotypes was observed and a dN/dS ratio of 0.64 was obtained, suggesting that a purifying selective pressure is acting on pe_pgrs33 against deleterious SNPs. Among a total of 19 pe_pgrs33 alleles identified in this study, 5 were cloned and used to complement the pe_pgrs33 knock-out mutant strain of Mtb H37Rv (Mtb\uce\u9433) to assess the functional impact of the respective polymorphisms in in vitro infections of primary macrophages. In human monocyte-derived macrophages (MDMs) infection, large in-frame and frameshift mutations were unable to restore the phenotype of Mtb H37Rv, impairing the cell entry capacity of Mtb, but neither its intracellular replication rate nor its immunomodulatory properties. In vivo studies performed in the murine model of tuberculosis (TB) demonstrated that the Mtb\uce\u9433 mutant strain was not impaired in the ability to infect and replicate in the lung tissue compared to the parental strain. Interestingly, Mtb\uce\u9433 showed an enhanced virulence during the chronic steps of infection compared to Mtb H37Rv. Similarly, the complementation of Mtb\uce\u9433 with a frameshift allele also resulted in a Mtb strain capable of causing a surprisingly enhanced tissue damage in murine lungs, during the chronic steps of infection. Together, these results further support the role of PE_PGRS33 in the pathogenesis and virulence of Mtb