Dynamics underlying epileptic seizures span multiple scales in space and time, therefore, understanding seizure mechanisms requires identifying the relations between seizure components within and across these scales, together with the analysis of their dynamical repertoire. In this view, mathematical models have been developed, ranging from single neuron to neural population. In this study, we consider a neural mass model able to exactly reproduce the dynamics of heterogeneous spiking neural networks. We combine mathematical modeling with structural information from non invasive brain imaging, thus building large-scale brain network models to explore emergent dynamics and test the clinical hypothesis. We provide a comprehensive study on the effect of external drives on neuronal networks exhibiting multistability, in order to investigate the role played by the neuroanatomical connectivity matrices in shaping the emergent dynamics. In particular, we systematically investigate the conditions under which the network displays a transition from a low activity regime to a high activity state, which we identify with a seizure-like event. This approach allows us to study the biophysical parameters and variables leading to multiple recruitment events at the network level. We further exploit topological network measures in order to explain the differences and the analogies among the subjects and their brain regions, in showing recruitment events at different parameter values. We demonstrate, along with the example of diffusion-weighted magnetic resonance imaging (dMRI) connectomes of 20 healthy subjects and 15 epileptic patients, that individual variations in structural connectivity, when linked with mathematical dynamic models, have the capacity to explain changes in spatiotemporal organization of brain dynamics, as observed in network-based brain disorders. In particular, for epileptic patients, by means of the integration of the clinical hypotheses on the epileptogenic zone (EZ), i.e., the local network where highly synchronous seizures originate, we have identified the sequence of recruitment events and discussed their links with the topological properties of the specific connectomes. The predictions made on the basis of the implemented set of exact mean-field equations turn out to be in line with the clinical pre-surgical evaluation on recruited secondary networks.

• Klíčová slova
• epileptic seizure-like event, neural mass model, patient-specific brain network model, quadratic integrate-and-fire neuron, topological network measure,
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: Reported brain abnormalities in anatomy and function in psychiatric and neurological patients led to a project based on qualitative electroencephalography examination and analysis in an attempt to find specific brain derived pattern--or sequence of brain locations involved in processing various stimuli--both visual and auditory. METHODS: Specialized software called Brain Activation Sequences was built according to our team member specifications (M.S.). The software utilizes event related potentials recorded during cognitive/emotion processing in participants (healthy controls, neurological patients and psychiatric patients) to calculate the sequence of brain areas using nonlinear and linear algorithms. RESULTS: Results show significant differences in activation patterns between patients and healthy controls as well as significant similarities within the groups of patients and controls in both performed testing experiments.

• MeSH
• dospělí MeSH
• elektroencefalografie MeSH
• evokované potenciály fyziologie   MeSH
• lidé MeSH
• mozek patofyziologie   MeSH
• narkolepsie patofyziologie   MeSH
• nervové dráhy patofyziologie   MeSH
• neuronové sítě MeSH
• poruchy příjmu potravy patofyziologie   MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: The default mode network (DMN) decreases its activity when switching from a resting state to a cognitive task condition, while activity of the network engaged in the given task increases. Visual processing is typically disturbed in Parkinson's disease dementia (PDD). OBJECTIVE: Using functional MRI, we studied the DMN effective connectivity patterns in PDD as compared with cognitively normal patients with Parkinson's disease (PD) and healthy controls (HC) when switching from baseline to a visual cognitive task condition. METHODS: In all, 14 PDD, 18 PD, and 18 age-matched healthy controls participated in this functional MRI study. We used a psychophysiological interaction analysis with the precuneus (PCu) as a seed. The threshold was set at p(FWE) <0.05. RESULTS: The healthy controls showed greater PCu connectivity with the bilateral middle temporal/middle occipital gyri at baseline than during the task condition. The correlation direction changed from positive to negative. Both PD and PDD showed disturbed DMN connectivity with the brain regions that are involved in bottom-up visual processing. In PD, we also found impaired integration of the areas engaged in the ventral attentional network, which might reflect specific attentional deficits observed during the early course of PD. In mild PDD, we detected increased engagement of areas involved in the dorsal attentional network, which corresponds to increased top-down control in this patient group as compared to the healthy controls. CONCLUSION: Our results show impaired dynamic interplay between large scale brain networks in PD that spread far beyond the motor system.

• Klíčová slova
• Default mode network, Parkinson's disease, dementia, functional MRI, precuneus, visual processing,
• MeSH
• atrofie etiologie   patologie   MeSH
• hyperkinetická porucha etiologie   MeSH
• kognitivní poruchy etiologie   patologie   MeSH
• kyslík krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mapování mozku MeSH
• modely neurologické MeSH
• nervové dráhy krevní zásobení   patologie   MeSH
• neuropsychologické testy MeSH
• Parkinsonova nemoc komplikace   patologie   MeSH
• počítačové zpracování obrazu MeSH
• poruchy zraku etiologie   patologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• světelná stimulace MeSH
• temenní lalok krevní zásobení   patologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyslík MeSH

Epilepsy presurgical investigation may include focal intracortical single-pulse electrical stimulations with depth electrodes, which induce cortico-cortical evoked potentials at distant sites because of white matter connectivity. Cortico-cortical evoked potentials provide a unique window on functional brain networks because they contain sufficient information to infer dynamical properties of large-scale brain connectivity, such as preferred directionality and propagation latencies. Here, we developed a biologically informed modelling approach to estimate the neural physiological parameters of brain functional networks from the cortico-cortical evoked potentials recorded in a large multicentric database. Specifically, we considered each cortico-cortical evoked potential as the output of a transient stimulus entering the stimulated region, which directly propagated to the recording region. Both regions were modelled as coupled neural mass models, the parameters of which were estimated from the first cortico-cortical evoked potential component, occurring before 80 ms, using dynamic causal modelling and Bayesian model inversion. This methodology was applied to the data of 780 patients with epilepsy from the F-TRACT database, providing a total of 34 354 bipolar stimulations and 774 445 cortico-cortical evoked potentials. The cortical mapping of the local excitatory and inhibitory synaptic time constants and of the axonal conduction delays between cortical regions was obtained at the population level using anatomy-based averaging procedures, based on the Lausanne2008 and the HCP-MMP1 parcellation schemes, containing 130 and 360 parcels, respectively. To rule out brain maturation effects, a separate analysis was performed for older (>15 years) and younger patients (<15 years). In the group of older subjects, we found that the cortico-cortical axonal conduction delays between parcels were globally short (median = 10.2 ms) and only 16% were larger than 20 ms. This was associated to a median velocity of 3.9 m/s. Although a general lengthening of these delays with the distance between the stimulating and recording contacts was observed across the cortex, some regions were less affected by this rule, such as the insula for which almost all efferent and afferent connections were faster than 10 ms. Synaptic time constants were found to be shorter in the sensorimotor, medial occipital and latero-temporal regions, than in other cortical areas. Finally, we found that axonal conduction delays were significantly larger in the group of subjects younger than 15 years, which corroborates that brain maturation increases the speed of brain dynamics. To our knowledge, this study is the first to provide a local estimation of axonal conduction delays and synaptic time constants across the whole human cortex in vivo, based on intracerebral electrophysiological recordings.

• Klíčová slova
• axonal conduction delay, cortico-cortical evoked potential, dynamic causal modelling, neural mass models, synaptic time constant,
• MeSH
• Bayesova věta MeSH
• elektrická stimulace metody   MeSH
• epilepsie * MeSH
• evokované potenciály * fyziologie   MeSH
• lidé MeSH
• mapování mozku metody   MeSH
• mozek MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The current evidence of cognitive disturbances and brain alterations in schizophrenia does not provide the plausible explanation of the underlying mechanisms. Neuropsychological studies outlined the cognitive profile of patients with schizophrenia, that embodied the substantial disturbances in perceptual and motor processes, spatial functions, verbal and non-verbal memory, processing speed and executive functioning. Standardized scoring in the majority of the neurocognitive tests renders the index scores or the achievement indicating the severity of the cognitive impairment rather than the actual performance by means of errors. At the same time, the quantitative evaluation may lead to the situation when two patients with the same index score of the particular cognitive test, demonstrate qualitatively different performances. This may support the view why test paradigms that habitually incorporate different cognitive variables associate weakly, reflecting an ambiguity in the interpretation of noted cognitive constructs. With minor exceptions, cognitive functions are not attributed to the localized activity but eventuate from the coordinated activity in the generally dispersed brain networks. Functional neuroimaging has progressively explored the connectivity in the brain networks in the absence of the specific task and during the task processing. The spatio-temporal fluctuations of the activity of the brain areas detected in the resting state and being highly reproducible in numerous studies, resemble the activation and communication patterns during the task performance. Relatedly, the activation in the specific brain regions oftentimes is attributed to a number of cognitive processes. Given the complex organization of the cognitive functions, it becomes crucial to designate the roles of the brain networks in relation to the specific cognitive functions. One possible approach is to identify the commonalities of the deficits across the number of cognitive tests or, common errors in the various tests and identify their common "denominators" in the brain networks. The qualitative characterization of cognitive performance might be beneficial in addressing diffuse cognitive alterations presumably caused by the dysconnectivity of the distributed brain networks. Therefore, in the review, we use this approach in the description of standardized tests in the scope of potential errors in patients with schizophrenia with a subsequent reference to the brain networks.

• Klíčová slova
• brain networks, cognitive deficits, cognitive tests, errors, fMRI, lesions, schizophrenia,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: Acute methanol poisoning leads to optic neuropathy and necrotic lesions of basal ganglia (BG) and subcortical white matter. Survivors of methanol poisoning exhibit long-term executive and memory deficits. Associations between brain volumetry parameters and cognitive sequelae of methanol poisoning are not known. The aim of our study was to identify long-term associations between the cognitive performance of survivors of methanol poisoning and the volume of the brain structures that are selectively vulnerable to methanol. METHODS: We conducted a cross-sectional follow-up study on a sample of patients (n = 33, age 50 ± 14 years, 82% males) who survived acute methanol poisoning during methanol mass poisoning outbreak from September 2012 till January 2013 in the Czech Republic. A battery of neuropsychological tests and brain magnetic resonance imaging were included in the clinical examination protocol. Specific brain structures (putamen, globus pallidus, nucleus caudatus, and frontal white matter) were selected as regions of interest, and their volumes were estimated using the MorphoBox prototype software. RESULTS: In robust multiple regression models, sustained visual attention performance (as assessed by Trail Making Test and Prague Stroop Test) was positively associated with BG structures and frontal white matter volumes (Wald = 9.03 to 85.50, p < 0.01), sensitivity to interference (as assessed by Frontal Battery Assessment) was negatively associated with frontal white matter volume (Wald = 35.44 to 42.25, p < 0.001), and motor performance (as assessed by Finger Tapping Test) was positively associated with globus pallidus and frontal white matter volumes (Wald = 9.66 to 13.29, p < 0.01). CONCLUSIONS: Our results demonstrate that smaller volumes of elements of BG-thalamocortical circuitry, namely the BG and frontal white matter, relate to attention and motor performance in methanol poisoning from a long-term perspective. Disruption of those functional circuits may underlie specific cognitive deficits observed in methanol poisoning.

• Klíčová slova
• Basal Ganglia, Methanol Poisoning, Psychomotor Speed, Subcortical White Matter, Sustained Visual Attention,
• MeSH
• bazální ganglia diagnostické zobrazování   MeSH
• bílá hmota diagnostické zobrazování   MeSH
• dospělí MeSH
• exekutivní funkce účinky léků   MeSH
• kognice účinky léků   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• methanol otrava   MeSH
• mozek diagnostické zobrazování   MeSH
• následné studie MeSH
• nervová síť diagnostické zobrazování   MeSH
• neuropsychologické testy MeSH
• paměť účinky léků   MeSH
• pozornost účinky léků   MeSH
• přežívající MeSH
• průřezové studie MeSH
• psychomotorický výkon účinky léků   MeSH
• senioři MeSH
• učení účinky léků   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• methanol MeSH

BACKGROUND: About every fourth patient with major depressive disorder (MDD) shows evidence of systemic inflammation. Previous studies have shown inflammation-depression associations of multiple serum inflammatory markers and multiple specific depressive symptoms. It remains unclear, however, if these associations extend to genetic/lifetime predisposition to higher inflammatory marker levels and what role metabolic factors such as Body Mass Index (BMI) play. It is also unclear whether inflammation-symptom associations reflect direct or indirect associations, which can be disentangled using network analysis. METHODS: This study examined associations of polygenic risk scores (PRSs) for immuno-metabolic markers (C-reactive protein [CRP], interleukin [IL]-6, IL-10, tumour necrosis factor [TNF]-α, BMI) with seven depressive symptoms in one general population sample, the UK Biobank study (n = 110,010), and two patient samples, the Munich Antidepressant Response Signature (MARS, n = 1058) and Sequenced Treatment Alternatives to Relieve Depression (STAR*D, n = 1143) studies. Network analysis was applied jointly for these samples using fused graphical least absolute shrinkage and selection operator (FGL) estimation as primary analysis and, individually, using unregularized model search estimation. Stability of results was assessed using bootstrapping and three consistency criteria were defined to appraise robustness and replicability of results across estimation methods, network bootstrapping, and samples. RESULTS: Network analysis results displayed to-be-expected PRS-PRS and symptom-symptom associations (termed edges), respectively, that were mostly positive. Using FGL estimation, results further suggested 28, 29, and six PRS-symptom edges in MARS, STAR*D, and UK Biobank samples, respectively. Unregularized model search estimation suggested three PRS-symptom edges in the UK Biobank sample. Applying our consistency criteria to these associations indicated that only the association of higher CRP PRS with greater changes in appetite fulfilled all three criteria. Four additional associations fulfilled at least two consistency criteria; specifically, higher CRP PRS was associated with greater fatigue and reduced anhedonia, higher TNF-α PRS was associated with greater fatigue, and higher BMI PRS with greater changes in appetite and anhedonia. Associations of the BMI PRS with anhedonia, however, showed an inconsistent valence across estimation methods. CONCLUSIONS: Genetic predisposition to higher systemic inflammatory markers are primarily associated with somatic/neurovegetative symptoms of depression such as changes in appetite and fatigue, consistent with previous studies based on circulating levels of inflammatory markers. We extend these findings by providing evidence that associations are direct (using network analysis) and extend to genetic predisposition to immuno-metabolic markers (using PRSs). Our findings can inform selection of patients with inflammation-related symptoms into clinical trials of immune-modulating drugs for MDD.

• Klíčová slova
• Body Mass Index, C-reactive protein, Depression, Depressive symptoms, Inflammation, Interleukin 10, Interleukin 6, Network analysis, Tumour necrosis factor-α,
• MeSH
• antidepresiva terapeutické užití   MeSH
• C-reaktivní protein analýza   MeSH
• deprese * genetika   MeSH
• depresivní porucha unipolární * farmakoterapie   genetika   MeSH
• lidé MeSH
• multifaktoriální dědičnost MeSH
• zánět farmakoterapie   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• antidepresiva MeSH
• C-reaktivní protein MeSH

Modern trends in psychology and cognitive neuroscience suggest that applications of nonlinear dynamics, chaos and self-organization seem to be particularly important for research of some fundamental problems regarding mind-brain relationship. Relevant problems among others are formations of memories during alterations of mental states and nature of a barrier that divides mental states, and leads to the process called dissociation. This process is related to a formation of groups of neurons which often synchronize their firing patterns in a unique spatial maner. Central theme of this study is the relationship between level of moving and oscilating mental processes and their neurophysiological substrate. This opens a question about principles of organization of conscious experiences and how these experiences arise in the brain. Chaotic self-organization provides a unique theoretical and experimental tool for deeper understanding of dissociative phenomena and enables to study how dissociative phenomena can be linked to epileptiform discharges which are related to various forms of psychological and somatic manifestations. Organizing principles that constitute human consciousness and other mental phenomena from this point of view may be described by analysis and reconstruction of underlying dynamics of psychological or psychophysiological measures. These nonlinear methods in this study were used for analysis of characteristic changes in EEG and bilateral electrodermal activity (EDA) during reliving of dissociated traumatic and stressful memories and during psychopathological states. Analysis confirms a possible role of chaotic transitions in the processing of dissociated memory. Supportive finding for a possible chaotic process related to dissociation found in this study represent also significant relationship of dissociation, epileptiform discharges measured by typical psychopathological manifestations and characteristic laterality changes in bilateral EDA in patients with schizophrenia and depression. Increased level of psychopathological symptoms indicates close relationship to the right-left EDA asymmetry and asymmetry of information entropy calculated by non-linear recurrence quantification analysis of EDA records. Because epileptiform activity has specific chaotic behaviour and calculated information entropy from EDA records reflects the complexity of the deterministic structure in the system there is a relevant assumption that unilaterally increased complexity may produce interhemispheric disbalance and increased chaoticity which hypothetically may serve as a dynamic source of epileptiform discharges related to trauma induced kindling mechanism. Specific form of chaotic inner organization which cannot be explained only as a consequence of external causality support also psychophysiological data that lead to the so-called self-organizing theory of dreaming by Kahn and Hobson. This study suggests that self-organizing theory of dreaming is particularly important with respect to problem of memory formation and processing during dissociative states characteristic for dreams. Recent data and also findings of this study support the research utility of chaos theory in psychology and neuroscience, and also its conceptual view of dynamic ordering factors and self-organization underlying psychological processes and brain physiology.

• MeSH
• dějiny 19. století MeSH
• dějiny 20. století MeSH
• disociační poruchy dějiny   patofyziologie   MeSH
• lidé MeSH
• mozek patofyziologie   MeSH
• nelineární dynamika * MeSH
• nervová síť patofyziologie   MeSH
• neurologie dějiny   MeSH
• psychiatrie dějiny   MeSH
• vědomí fyziologie   MeSH
• Check Tag
• dějiny 19. století MeSH
• dějiny 20. století MeSH
• lidé MeSH
• Publikační typ
• biografie MeSH
• časopisecké články MeSH
• historické články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Francie MeSH
• Rakousko MeSH
• Spojené státy americké MeSH
• Švýcarsko MeSH

• O autorovi
• Janet, Pierre
• Freud, Sigmund
• Breuer, Joseph
• Jung, Carl Gustav
• Bleuler, Eugen

Visual processing difficulties are often present in Alzheimer's disease (AD), even in its pre-dementia phase (i.e. in mild cognitive impairment, MCI). The default mode network (DMN) modulates the brain connectivity depending on the specific cognitive demand, including visual processes. The aim of the present study was to analyze specific changes in connectivity of the posterior DMN node (i.e. the posterior cingulate cortex and precuneus, PCC/P) associated with visual processing in 17 MCI patients and 15 AD patients as compared to 18 healthy controls (HC) using functional magnetic resonance imaging. We used psychophysiological interaction (PPI) analysis to detect specific alterations in PCC connectivity associated with visual processing while controlling for brain atrophy. In the HC group, we observed physiological changes in PCC connectivity in ventral visual stream areas and with PCC/P during the visual task, reflecting the successful involvement of these regions in visual processing. In the MCI group, the PCC connectivity changes were disturbed and remained significant only with the anterior precuneus. In between-group comparison, we observed significant PPI effects in the right superior temporal gyrus in both MCI and AD as compared to HC. This change in connectivity may reflect ineffective "compensatory" mechanism present in the early pre-dementia stages of AD or abnormal modulation of brain connectivity due to the disease pathology. With the disease progression, these changes become more evident but less efficient in terms of compensation. This approach can separate the MCI from HC with 77% sensitivity and 89% specificity.

• Klíčová slova
• Dementia, Posterior cingulate, Precuneus, Psychophysiological interactions, Visual pathways, fMRI,
• MeSH
• Alzheimerova nemoc komplikace   MeSH
• kognitivní dysfunkce diagnostické zobrazování   etiologie   patologie   MeSH
• kyslík krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• modely neurologické MeSH
• mozek patologie   MeSH
• nervové dráhy diagnostické zobrazování   patofyziologie   MeSH
• počítačové zpracování obrazu MeSH
• psychofyzika MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stárnutí * MeSH
• světelná stimulace MeSH
• zraková percepce fyziologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyslík MeSH

The SITS (Safe Implementation of Thrombolysis in Stroke)-EAST project was launched in 2007 to support evidence-based stroke treatments, including thrombolytic treatments (TLTs), in Central and Eastern Europe. The aim of this study was to detail the topography, efficacy, and specific characteristics of stroke centers in the Czech Republic (CZ), the country with the highest rate of TLT. The nationwide study was performed between September and November 2007 through a questionnaire sent to all centers registered in SITS. The questionnaire contained 25 questions addressing how centers met recommendations for primary and comprehensive stroke centers in 2006. Center characteristics predicting the number of TLTs were identified by multiple regression analysis. Altogether, data were obtained from 42 centers (88% response rate) with the following characteristics [median (min-max)]: catchment area population 150,000 (90,000-750,000); number of strokes/year 420 (150-1,589); number of TLTs 7.5 (2-45); number of physicians specialized in stroke 3 (1-7). Centers treated 4.3% of the patients with ischemic strokes with tissue plasminogen activator. A stroke unit was present in 32 (78%) departments. Rescue interventional therapies were performed in 11 (26%). Financial problems restricted TLT in 14 (35%) centers. Fourteen factors were associated with the number of TLTs in univariate regression analysis, but in multiple regression analysis, only the catchment area population (p < 0.001), >3 physicians specialized in stroke (p < 0.001), and the presence of an acute interventional program (p < 0.006) remained significant. This study provides the fundamental stroke treatment network data that are essential for certification and further SITS-EAST TLT expansion.

• MeSH
• časové faktory MeSH
• cévní mozková příhoda ekonomika   terapie   MeSH
• ischemie mozku ekonomika   terapie   MeSH
• jednotky nemocniční * ekonomika   statistika a číselné údaje   MeSH
• lékaři statistika a číselné údaje   MeSH
• lékařství statistika a číselné údaje   MeSH
• lidé MeSH
• lineární modely MeSH
• multivariační analýza MeSH
• populace MeSH
• průzkumy a dotazníky MeSH
• regresní analýza MeSH
• tkáňový aktivátor plazminogenu terapeutické užití   MeSH
• tomografy rentgenové počítačové statistika a číselné údaje   MeSH
• trombolytická terapie * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• tkáňový aktivátor plazminogenu MeSH