Mechanisms responsible for the integration of perceptual events and appropriate actions (sensorimotor processes) have been subject to intense research. Different theoretical frameworks have been put forward with the "Theory of Event Coding (TEC)" being one of the most influential. In the current study, we focus on the concept of 'event files' within TEC and examine what sub-processes being dissociable by means of cognitive-neurophysiological methods are involved in voluntary event coding. This was combined with EEG source localization. We also introduce reward manipulations to delineate the neurophysiological sub-processes most relevant for performance variations during event coding. The results show that processes involved in voluntary event coding included predominantly stimulus categorization, feature unbinding and response selection, which were reflected by distinct neurophysiological processes (the P1, N2 and P3 ERPs). On a system's neurophysiological level, voluntary event-file coding is thus related to widely distributed parietal-medial frontal networks. Attentional selection processes (N1 ERP) turned out to be less important. Reward modulated stimulus categorization in parietal regions likely reflecting aspects of perceptual decision making but not in other processes. The perceptual categorization stage appears central for voluntary event-file coding.

• Klíčová slova
• Categorization, EEG, Event files, Perception, Response selection, Source localization, Theory of event coding,
• MeSH
• dospělí MeSH
• kognice fyziologie   MeSH
• lidé MeSH
• modely neurologické * MeSH
• odměna * MeSH
• plnění a analýza úkolů * MeSH
• počítačová simulace MeSH
• somatosenzorické korové centrum fyziologie   MeSH
• ukládání a vyhledávání informací metody   MeSH
• vůle fyziologie   MeSH
• zraková percepce fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Gilles de la Tourette syndrome (GTS) is a common multifaceted neuropsychiatric disorder. Research in GTS has traditionally focussed on mechanisms underlying changes in motor processes in these patients. There is, however, growing interest in GTS related sensory phenomena. According to the Theory of Event-coding (TEC), sensory stimuli do not only serve representational functions but also action-related functions. In the current study, we use the TEC framework to examine whether the way perceptual features are processed is altered in GTS. The results show that basic perceptual processes differ between GTS patients and healthy controls which might be central for the understanding of this disorder. Details or features of perceptual objects were less bound in GTS suggesting that perceptual features integration is attenuated in them. Behavioural findings were unrelated to patient characteristics implying that they might represent trait abnormalities. It is possible that altered perceptual processing in GTS is due to a long-range under-connectivity of parietal areas with other brain regions repeatedly been described in these patients.

• Klíčová slova
• Feature integration, Gilles de la Tourette syndrome, Object file, Perception, Theory of Event-coding,
• MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• orientace fyziologie   MeSH
• reakční čas fyziologie   MeSH
• světelná stimulace MeSH
• Tourettův syndrom patofyziologie   MeSH
• vnímání barev fyziologie   MeSH
• zraková percepce fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The computational simulation of photo-induced processes in large molecular systems is a very challenging problem. Firstly, to properly simulate photo-induced reactions the potential energy surfaces corresponding to excited states must be appropriately accessed; secondly, understanding the mechanisms of these processes requires the exploration of complex configurational spaces and the localization of conical intersections; finally, photo-induced reactions are probability events, that require the simulation of hundreds of trajectories to obtain the statistical information for the analysis of the reaction profiles. Here, we present a detailed description of our implementation of a molecular dynamics with electronic transitions algorithm within the local-orbital density functional theory code FIREBALL, suitable for the computational study of these problems. As an example of the application of this approach, we also report results on the [2 + 2] cycloaddition of ethylene with maleic anhydride and on the [2 + 2] photo-induced polymerization reaction of two C60 molecules. We identify different deactivation channels of the initial electron excitation, depending on the time of the electronic transition from LUMO to HOMO, and the character of the HOMO after the transition.

• MeSH
• algoritmy MeSH
• elektronika * MeSH
• elektrony MeSH
• ethyleny chemie   MeSH
• fullereny chemie   MeSH
• kvantová teorie * MeSH
• maleinanhydridy chemie   MeSH
• molekulární modely MeSH
• počítačová simulace MeSH
• simulace molekulární dynamiky * MeSH
• světlo * MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ethylene MeSH Prohlížeč
• ethyleny MeSH
• fullerene C60 MeSH Prohlížeč
• fullereny MeSH
• maleinanhydridy MeSH

The nature of neural codes is central to neuroscience. Do neurons encode information through relatively slow changes in the firing rates of individual spikes (rate code) or by the precise timing of every spike (temporal code)? Here we compare the loss of information due to correlations for these two possible neural codes. The essence of Shannon's definition of information is to combine information with uncertainty: the higher the uncertainty of a given event, the more information is conveyed by that event. Correlations can reduce uncertainty or the amount of information, but by how much? In this paper we address this question by a direct comparison of the information per symbol conveyed by the words coming from a binary Markov source (temporal code) with the information per symbol coming from the corresponding Bernoulli source (uncorrelated, rate code). In a previous paper we found that a crucial role in the relation between information transmission rates (ITRs) and firing rates is played by a parameter s, which is the sum of transition probabilities from the no-spike state to the spike state and vice versa. We found that in this case too a crucial role is played by the same parameter s. We calculated the maximal and minimal bounds of the quotient of ITRs for these sources. Next, making use of the entropy grouping axiom, we determined the loss of information in a Markov source compared with the information in the corresponding Bernoulli source for a given word length. Our results show that in the case of correlated signals the loss of information is relatively small, and thus temporal codes, which are more energetically efficient, can replace rate codes effectively. These results were confirmed by experiments.

• Klíčová slova
• Shannon information theory, firing rate, information source, information transmission rate, neural coding,
• MeSH
• akční potenciály * MeSH
• informační teorie * MeSH
• Markovovy řetězce * MeSH
• modely neurologické * MeSH
• nejistota * MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

The evolutionary past of intragenic repeats in protein-coding exons of c-, N-, L-, and s-myc-protooncogene subfamilies was elucidated. Apparently these genes evolved by succession of distinct unit events rather than by a steady flow of random point mutations. An evolutionary event probably involved a duplication of the whole gene, which was followed by amplification of progressively shorter oligonucleotide themes and motifs. The repeats were either joined in tandem or one of the copies was transposed and integrated elsewhere within the same exon. In some instances multiple fragments of an amplified theme were integrated at several sites. Direct repeats were found to prevail over inverted ones. By reconstructing the fate of repeats in the course of evolution of vertebrates, the origins of some functional domains could be traced to the initial amplification event. For example, an N-myc-specific domain was created by tandem duplication of a single-copy theme of L-myc exon; at the time of divergence of the c-myc and N-myc, the tandem duplex underwent a new round of duplication followed by transposition of the new copy, thus accounting for the formation of a new domain specific for c-myc. The model proposed here may be regarded as a molecular-level equivalent of the theory of punctuated equilibria.

• MeSH
• exony genetika   MeSH
• frekvence genu MeSH
• geny myc * MeSH
• Hominidae genetika   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• molekulární evoluce * MeSH
• molekulární sekvence - údaje MeSH
• multigenová rodina * MeSH
• myši MeSH
• obratlovci genetika   MeSH
• oligonukleotidy genetika   MeSH
• repetitivní sekvence nukleových kyselin MeSH
• sekvence nukleotidů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• oligonukleotidy MeSH

BACKGROUND AND AIMS: The centromere drive theory explains diversity of eukaryotic centromeres as a consequence of the recurrent conflict between centromeric repeats and centromeric histone H3 (CenH3), in which selfish centromeres exploit meiotic asymmetry and CenH3 evolves adaptively to counterbalance deleterious consequences of driving centromeres. Accordingly, adaptively evolving CenH3 has so far been observed only in eukaryotes with asymmetric meiosis. However, if such evolution is a consequence of centromere drive, it should depend not only on meiotic asymmetry but also on monocentric or holokinetic chromosomal structure. Selective pressures acting on CenH3 have never been investigated in organisms with holokinetic meiosis despite the fact that holokinetic chromosomes have been hypothesized to suppress centromere drive. Therefore, the present study evaluates selective pressures acting on the CenH3 gene in holokinetic organisms for the first time, specifically in the representatives of the plant genus Luzula (Juncaceae), in which the kinetochore formation is not co-localized with any type of centromeric repeat. METHODS: PCR, cloning and sequencing, and database searches were used to obtain coding CenH3 sequences from Luzula species. Codon substitution models were employed to infer selective regimes acting on CenH3 in Luzula KEY RESULTS: In addition to the two previously published CenH3 sequences from L. nivea, 16 new CenH3 sequences have been isolated from 12 Luzula species. Two CenH3 isoforms in Luzula that originated by a duplication event prior to the divergence of analysed species were found. No signs of positive selection acting on CenH3 in Luzula were detected. Instead, evidence was found that selection on CenH3 of Luzula might have been relaxed. CONCLUSIONS: The results indicate that holokinetism itself may suppress centromere drive and, therefore, holokinetic chromosomes might have evolved as a defence against centromere drive.

• Klíčová slova
• CenH3, Luzula, centromere drive, holokinetic chromosomes, positive selection,
• MeSH
• centromera genetika   MeSH
• chromozomy rostlin genetika   MeSH
• fylogeneze MeSH
• genom rostlinný genetika   MeSH
• histony genetika   MeSH
• Magnoliopsida genetika   MeSH
• meióza genetika   MeSH
• sekvenční analýza DNA MeSH
• sekvenční seřazení MeSH
• selekce (genetika) genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histony MeSH

Aging is a process drawing attention of many researchers, and at present many theories exists, which try to explain this chain of inevitable events leading to death of organism. In this article we focused our attention on a theory explaining the degenerative changes occurring during aging by the effect of oxygen free radicals. These highly reactive radicals are produced during oxidative phosphorylation in mitochondria. All cellular components appear to be sensitive to oxygen-radical damage. Lipids, proteins and nucleic acids are probably the most susceptible to this injury. Lipoperoxidation of lipids together with cross-linking of proteins with phospholipids and nucleic acids caused changes in membrane fluidity. Mitochondrial DNA coding several subunits of respiratory chain enzymes can be also damaged by these radicals. All these changes together have negative impact on mitochondrial metabolism resulting progressive decrease of the efficiency of oxidative phosphorylation and thus of the whole organism.

• MeSH
• energetický metabolismus MeSH
• lidé MeSH
• mitochondrie fyziologie   MeSH
• stárnutí fyziologie   MeSH
• volné radikály MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH
• úvodníky MeSH
• Názvy látek
• volné radikály MeSH

BACKGROUND: During the worldwide COVID-19 pandemic crisis, the role of digital contact tracing (DCT) intensified. However, the uptake of this technology expectedly differed among age cohorts and national cultures. Various conceptual tools were introduced to strengthen DCT research from a theoretical perspective. However, little has been done to compare theory-supported findings across different cultural contexts and age cohorts. OBJECTIVE: Building on the original study conducted in Belgium in April 2020 and theoretically underpinned by the Health Belief Model (HBM), this study attempted to confirm the predictors of DCT adoption in a cultural environment different from the original setting, that is, the Czech Republic. In addition, by using brief qualitative evidence, it aimed to shed light on the possible limitations of the HBM in the examined context and to propose certain extensions of the HBM. METHODS: A Czech version of the original instrument was administered to a convenience sample of young (aged 18-29 y) Czech adults in November 2020. After filtering, 519 valid responses were obtained and included in the quantitative data analysis, which used structural equation modeling and followed the proposed structure of the relationships among the HBM constructs. Furthermore, a qualitative thematic analysis of the free-text answers was conducted to provide additional insights about the model's validity in the given context. RESULTS: The proposed measurement model exhibited less optimal fit (root mean square error of approximation=0.065, 90% CI 0.060-0.070) than in the original study (root mean square error of approximation=0.036, 90% CI 0.033-0.039). Nevertheless, perceived benefits and perceived barriers were confirmed as the main, statistically significant predictors of DCT uptake, consistent with the original study (β=.60, P<.001 and β=-.39; P<.001, respectively). Differently from the original study, self-efficacy was not a significant predictor in the strict statistical sense (β=.12; P=.003). In addition, qualitative analysis demonstrated that in the given cohort, perceived barriers was the most frequent theme (166/354, 46.9% of total codes). Under this category, psychological fears and concerns was a subtheme, notably diverging from the original operationalization of the perceived barriers construct. In a similar sense, a role for social influence in DCT uptake processes was suggested by some respondents (12/354, 1.7% of total codes). In summary, the quantitative and qualitative results indicated that the proposed quantitative model seemed to be of limited value in the examined context. CONCLUSIONS: Future studies should focus on reconceptualizing the 2 underperforming constructs (ie, perceived severity and cues to action) by considering the qualitative findings. This study also provided actionable insights for policy makers and app developers to mitigate DCT adoption issues in the event of a future pandemic caused by unknown viral agents.

• Klíčová slova
• COVID-19, Health Belief Model, Health Belief Model approach, contact tracing, digital contact tracing, eMask, eRouska, pandemic crisis, proximity tracing, qualitative verification, technology adoption,
• MeSH
• COVID-19 * epidemiologie   MeSH
• lidé MeSH
• mladiství MeSH
• mobilní aplikace * MeSH
• pandemie MeSH
• srovnání kultur MeSH
• trasování kontaktů metody   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH