The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical ...branching process exhibits the same exponent Formula: see text. Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Scale-invariant neuronal avalanches have been observed in cell cultures and slices as well as anesthetized and awake brains, suggesting that the brain operates near criticality, i.e. within a narrow ...margin between avalanche propagation and extinction. In theory, criticality provides many desirable features for the behaving brain, optimizing computational capabilities, information transmission, sensitivity to sensory stimuli and size of memory repertoires. However, a thorough characterization of neuronal avalanches in freely-behaving (FB) animals is still missing, thus raising doubts about their relevance for brain function.
To address this issue, we employed chronically implanted multielectrode arrays (MEA) to record avalanches of action potentials (spikes) from the cerebral cortex and hippocampus of 14 rats, as they spontaneously traversed the wake-sleep cycle, explored novel objects or were subjected to anesthesia (AN). We then modeled spike avalanches to evaluate the impact of sparse MEA sampling on their statistics. We found that the size distribution of spike avalanches are well fit by lognormal distributions in FB animals, and by truncated power laws in the AN group. FB data surrogation markedly decreases the tail of the distribution, i.e. spike shuffling destroys the largest avalanches. The FB data are also characterized by multiple key features compatible with criticality in the temporal domain, such as 1/f spectra and long-term correlations as measured by detrended fluctuation analysis. These signatures are very stable across waking, slow-wave sleep and rapid-eye-movement sleep, but collapse during anesthesia. Likewise, waiting time distributions obey a single scaling function during all natural behavioral states, but not during anesthesia. Results are equivalent for neuronal ensembles recorded from visual and tactile areas of the cerebral cortex, as well as the hippocampus.
Altogether, the data provide a comprehensive link between behavior and brain criticality, revealing a unique scale-invariant regime of spike avalanches across all major behaviors.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Nanoparticle mediated hyperthermia has been explored as a method to increase cancer treatment efficacy by heating tumours inside-out. With that purpose, nanoparticles have been designed and their ...properties tailored to respond to external stimuli and convert the supplied energy into heat, therefore inducing damage to tumour cells. Moreover, the combination of hyperthermia with chemotherapy has been described as a more effective strategy due to the synergy between the high temperature and the drug’s effects, also associated with a remote controlled and on-demand drug release. In this review, the methods behind nanoparticle mediated hyperthermia, namely material design, external stimuli response and energy conversion will be discussed and critically analysed. We will address the most relevant studies on hyperthermia and temperature triggered drug release for cancer treatment. Finally, the advantages, difficulties and challenges of this therapeutic strategy will be discussed, while giving insight for future developments.
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•Nanoparticles correct the non-specific mode of action of chemotherapy.•Hyperthermia works as an adjuvant in cancer therapy•Hyperthermia sensitizes cancer cells to chemotherapy.•Hyperthermia can be induced through several external stimuli.•Stimuli responsive nanomaterials allow for a remote-controlled drug release.
Human adipose tissue-derived stem cells (hASC) secretome display various therapeutically relevant effects in regenerative medicine, such as induction of angiogenesis and tissue repair. The benefits ...of hASC secretome are primarily orchestrated by trophic factors that mediate autocrine and paracrine effects in host cells. However, the composition and the innate characteristics of hASC secretome can be highly variable depending on the culture conditions. Here, we evaluated the combined effect of serum-free media and hypoxia preconditioning on the hASCs secretome composition and biological effects on angiogenesis and wound healing. The hASCs were cultured in serum-free media under normoxic (NCM) or hypoxic (HCM) preconditioning. The proteomic profile showed that pro- and anti-antiangiogenic factors were detected in NCM and HCM secretomes. In vitro studies demonstrated that hASCs secretomes enhanced endothelial proliferation, survival, migration, in vitro tube formation, and in vivo Matrigel plug angiogenesis. In a full-thickness skin-wound mouse model, injection of either NCM or HCM significantly accelerated the wound healing. Finally, hASC secretomes were potent in increasing endothelial density and vascular coverage of resident pericytes expressing NG2 and nestin to the lesion site, potentially contributing to blood vessel maturation. Overall, our data suggest that serum-free media or hypoxic preconditioning enhances the vascular regenerative effects of hASC secretome in a preclinical wound healing model.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Stereotypies are frequently reported in people with autism spectrum disorder (ASD) but remain one of the less explained phenomena. We aimed to describe, through a systematic review and a ...meta-analysis, the prevalence of motor stereotypies in ASD and study the factors that influence this prevalence. Our literature search included MEDLINE, Scopus, and PsycINFO databases. Quality and risk of bias were assessed. Thirty-seven studies were included and the median prevalence of motor stereotypies in ASD was 51.8%, ranging from 21.9% to 97.5%. The most frequent determinants associated with a higher number of stereotypies in ASD were a younger age, lower intelligence quotient, and a greater severity of ASD. Moreover, gender did not seem to influence the prevalence of stereotypies. Meta-analytic analysis showed that lower IQ and autism diagnosis (independent of IQ) are associated with a higher prevalence of motor stereotypies (odds ratio = 2.5 and 4.7, respectively). Limitations of the reviewed literature include the use of convenience samples, with small sizes and heterogeneous inclusion criteria, and the predominance of high-functioning autism individuals.
A
bstract
We consider, in more details than it was done previously, the effective low- energy behavior in the quantum theory of a light scalar field coupled to another scalar with much larger mass. ...The main target of our work is an IR decoupling of heavy degrees of freedom, including in the diagrams with mixed light-heavy contents in the loops. It is shown that the one-loop diagrams with mixed internal lines produce an IR non-local contributions which are exactly the same as the ones in the theory of the light scalar alone, with the effective self-interaction which can be obtained by the functional integration of the heavy scalar, almost neglecting its kinetic term. The same effect takes place in curved space, regardless of a larger amount of non-localities which show up in the effective model.
Objectives: Cerebral small vessel disease is a chronic, progressive disorder of arterioles, capillaries, and small veins supplying the brain’s white matter and deep structures of gray matter. The ...latest evidence seems to suggest that chronic oral infections such as periodontitis contribute to cerebral small vessel disease progression. This study evaluated the relationship between periodontal disease and brain white matter hyperintensities. Methods: Forty-three hypertensive patients, aged between 38-82, without previous cardiovascular events, of which 42% were female and 50% diabetic, were evaluated. An association between mean probing depth, mean attachment level, bleeding on probing, total periodontal inflamed surface area, and white matter hyperintensities diagnosed by magnetic resonance was studied. A significance level (α) of 0.05 was considered, and Pearson’s chi-square and Mann–Whitney tests were applied. Results: Data analysis revealed an inverse correlation between mean probing depth, bleeding on probing, total periodontal inflamed surface area, and white matter hyperintensities. A positive correlation was found between mean attachment level and white matter hyperintensities. Conclusions: In our study and within our sample, lower values of mean probing depth, bleeding on probing, and total periodontal inflamed surface area were associated with more white matter hyperintensities. Contrarily, mean attachment level was positively associated with white matter hyperintensities.
This article analyses the status and trends of the European Union (EU) residential energy consumption in light of the energy consumption targets set by the EU 2020 and 2030 energy and climate ...strategies. It assesses the energy efficiency progress from 2000 to 2016, using the official Eurostat data. In 2016, the residential energy consumption amounted to 25.71% of the EU’s final energy consumption, representing the second largest consuming sector after transport. Consumption-related data are discussed together with data on some main energy efficiency policies and energy consumption determinants, such as economic and population growth, weather conditions, and household and building characteristics. Indicators are identified to show the impact of specific determinants on energy consumption and a new indicator is proposed, drawing a closer link between energy trends and policy and technological changes in the sector. The analysis of these determinants highlights the complex dynamics behind the demand of energy in the residential sector. Decomposition analysis is carried out using the Logarithmic Mean Divisia Index technique to provide a more complete picture of the impact of various determinants (population, wealth, intensity, and weather) on the latest EU-28 residential energy consumption trends. The article provides a better understanding of the EU residential energy consumption, its drivers, the impact of current policies, and recommendations on future policies.
Sensory events, cognitive processing and motor actions correlate with transient changes in neuronal activity. In cortex, these transients form widespread spatiotemporal patterns with largely unknown ...statistical regularities. Here, we show that activity associated with behavioral events carry the signature of scale-invariant spatiotemporal clusters, neuronal avalanches. Using high-density microelectrode arrays in nonhuman primates, we recorded extracellular unit activity and the local field potential (LFP) in premotor and prefrontal cortex during motor and cognitive tasks. Unit activity and negative LFP deflections (nLFP) consistently changed in rate at single electrodes during tasks. Accordingly, nLFP clusters on the array deviated from scale-invariance compared to ongoing activity. Scale-invariance was recovered using 'adaptive binning', that is identifying clusters at temporal resolution given by task-induced changes in nLFP rate. Measures of LFP synchronization confirmed and computer simulations detailed our findings. We suggest optimization principles identified for avalanches during ongoing activity to apply to cortical information processing during behavior.
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