dynamic brain activity
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- MeSH
- radioisotopová scintigrafie metody přístrojové vybavení MeSH
- vény abnormality MeSH
- Publikační typ
- kazuistiky MeSH
Error detection in motor behavior is a fundamental cognitive function heavily relying on local cortical information processing. Neural activity in the high-gamma frequency band (HGB) closely reflects such local cortical processing, but little is known about its role in error processing, particularly in the healthy human brain. Here we characterize the error-related response of the human brain based on data obtained with noninvasive EEG optimized for HGB mapping in 31 healthy subjects (15 females, 16 males), and additional intracranial EEG data from 9 epilepsy patients (4 females, 5 males). Our findings reveal a multiscale picture of the global and local dynamics of error-related HGB activity in the human brain. On the global level as reflected in the noninvasive EEG, the error-related response started with an early component dominated by anterior brain regions, followed by a shift to parietal regions, and a subsequent phase characterized by sustained parietal HGB activity. This phase lasted for more than 1 s after the error onset. On the local level reflected in the intracranial EEG, a cascade of both transient and sustained error-related responses involved an even more extended network, spanning beyond frontal and parietal regions to the insula and the hippocampus. HGB mapping appeared especially well suited to investigate late, sustained components of the error response, possibly linked to downstream functional stages such as error-related learning and behavioral adaptation. Our findings establish the basic spatio-temporal properties of HGB activity as a neural correlate of error processing, complementing traditional error-related potential studies.
- MeSH
- dospělí MeSH
- elektroencefalografie MeSH
- elektrokortikografie MeSH
- gama rytmus EEG fyziologie MeSH
- lidé MeSH
- mapování mozku metody MeSH
- mladý dospělý MeSH
- mozek fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nervové systémy mozku vykazují charakteristické vzorce časové korelace, jež jsou výsledkem funkční interakce složité strukturální sítě. Ve světle nových studií přibývají důkazy o tom, že tyto specifické vzorce nervové aktivace a funkční konektivity jsou neuronálním korelátem percepČních a kognitivních procesů. Článek přináší pohled na dynamické systémy mozku a jejich funkční a efektivní konektivitu a na metody, jež umožňují jejich deskripci.
Neural systems exhibit characteristic patterns of temporal correlations that emerge as the result of functional interactions within a structural network. There is mounting evidence that specific patterns of neuronal activation as well as patterns of functional connectivity are possible neural correlates of perceptual and cognitive processes. The article reviews the dynamic brain systems and their functional and effective connectivity as well as methods, which allow the description of these processes.
- MeSH
- centrální nervový systém fyziologie MeSH
- elektroencefalografie metody využití MeSH
- elektromagnetická pole MeSH
- finanční podpora výzkumu jako téma MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- magnetoencefalografie metody využití MeSH
- mozek anatomie a histologie patofyziologie patologie MeSH
- systémová teorie MeSH
- tomografie metody MeSH
- Check Tag
- lidé MeSH
Dissociated states represent pathological conditions where psychological trauma may emerge in a variety of forms such as psychic dissociative symptoms (hallucinations, derealization etc.) or on the other hand as somatoform symptoms (paroxysms, loss of motor control, involuntary movements etc.). Recent findings suggest that neurophysiological level of dissociative phenomena may be linked to the same neurophysiological principles that emerge in multi-stable perception of ambiguous stimuli likely caused by competing interpretations with mutual exclusivity. At this time there is evidence that temporal lobe seizure activity can produce dissociative syndrome and from these findings may be inferred that temporal lobe epileptic activity existing independently of neurological focal may share common neurobiological mechanism with dissociative symptoms. This conceptualization of dissociative phenomena is also in accordance with findings that originate from the study of the relationship between epilepsy and mental illness. The relationship was for the first time described in Meduna's concept of antagonism between epilepsy and psychosis and from the study of forced normalization introduced by Landolt in 1950s. The findings reported similar pathological conditions as in dissociative states when psychopathological symptoms and paroxysms may represent two different forms of the pathological process. Following the concept of forced normalization Tellenbach in 1965 introduced the term alternative psychosis implicating that stopping seizures does not mean vanishing or inactivity of the pathological state and that the epilepsy is still active subcortically and supplies energy for psychopathological symptoms. In the present review chaos in brain neural networks as a possible explanation of the relationship between dissociation and epileptic activity has been suggested that represents testable hypothesis for future research.
- MeSH
- disociační poruchy etiologie patofyziologie psychologie MeSH
- epilepsie temporálního laloku komplikace MeSH
- financování organizované MeSH
- lidé MeSH
- mozek fyziologie MeSH
- neuronové sítě MeSH
- paměť MeSH
- psychotické poruchy patofyziologie MeSH
- vědomí MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
We spend much our lives interacting with others in various social contexts. Although we deal with this myriad of interpersonal exchanges with apparent ease, each one relies upon a broad array of sophisticated cognitive processes. Recent research suggests that the cognitive operations supporting interactive behaviour are themselves underpinned by several canonical functional brain networks (CFNs) that integrate dynamically with one another in response to changing situational demands. Dynamic integrations among these CFNs should therefore play a pivotal role in coordinating interpersonal behaviour. Further, different types of interaction should present different demands on cognitive systems, thereby eliciting distinct patterns of dynamism among these CFNs. To investigate this, the present study performed functional magnetic resonance imaging (fMRI) on 30 individuals while they interacted with one another cooperatively or competitively. By applying a novel combination of analytical techniques to these brain imaging data, we identify six states of dynamic functional connectivity characterised by distinct patterns of integration and segregation among specific CFNs that differ systematically between these opposing types of interaction. Moreover, applying these same states to fMRI data acquired from an independent sample engaged in the same kinds of interaction, we were able to classify interpersonal exchanges as cooperative or competitive. These results provide the first direct evidence for the systematic involvement of CFNs during social interactions, which should guide neurocognitive models of interactive behaviour and investigations into biomarkers for the interpersonal dysfunction characterizing many neurological and psychiatric disorders.
- MeSH
- duševní poruchy * MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- mapování mozku MeSH
- mozek fyziologie MeSH
- sociální interakce * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Cannabis, and specifically one of its active compounds delta-9-tetrahydrocannabinol in recreational doses, has a variety of effects on cognitive processes. Most studies employ resting state functional magnetic resonance imaging techniques to assess the stationary effects of cannabis and to-date one report addressed the impact of delta-9-tetrahydrocannabinol on the dynamics of whole-brain functional connectivity. METHODS: Using a repeated-measures, within-subjects design, 19 healthy occasional cannabis users (smoking cannabis ⩽2 per week) underwent resting state functional magnetic resonance imaging scans. Each subject underwent two scans: in the intoxicated condition, shortly after smoking a cannabis cigarette, and in the non-intoxicated condition, with the subject being free from cannabinoids for at least one week before. All sessions were randomized and performed in a four-week interval. Data were analysed employing a standard independent component analysis approach with subsequent tracking of the functional connectivity dynamics, which allowed six connectivity clusters (states) to be individuated. RESULTS: Using standard independent component analysis in resting state functional connectivity, a group effect was found in the precuneus connectivity. With a dynamic independent component analysis approach, we identified one transient connectivity state, characterized by high connectivity within and between auditory and somato-motor cortices and anti-correlation with subcortical structures and the cerebellum that was only found during the intoxicated condition. Behavioural measures of the subjective experiences of changed perceptions and tetrahydrocannabinol plasma levels during intoxication were associated with this state. CONCLUSIONS: With the help of the dynamic connectivity approach we could elucidate neural correlates of the transitory perceptual changes induced by delta-9-tetrahydrocannabinol in cannabis users, and possibly identify a biomarker of cannabis intoxication.
- MeSH
- dospělí MeSH
- halucinogeny farmakologie MeSH
- kouření marihuany psychologie MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mladý dospělý MeSH
- mozek diagnostické zobrazování účinky léků MeSH
- tetrahydrokanabinol farmakologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie MeSH
- Research Support, N.I.H., Extramural MeSH
Pathological states in the central nervous system lead to dramatic changes in the activity of neuroactive substances in the extracellular space, to changes in ionic homeostasis and often to cell swelling. To quantify changes in cell morphology over a certain period of time, we employed a new technique, three-dimensional confocal morphometry. In our experiments, performed on enhanced green fluorescent protein/glial fibrillary acidic protein astrocytes in brain slices in situ and thus preserving the extracellular microenvironment, confocal morphometry revealed that the application of hypotonic solution evoked two types of volume change. In one population of astrocytes, hypotonic stress evoked small cell volume changes followed by a regulatory volume decrease, while in the second population volume changes were significantly larger without subsequent volume regulation. Three-dimensional cell reconstruction revealed that even though the total astrocyte volume increased during hypotonic stress, the morphological changes in various cell compartments and processes were more complex than have been previously shown, including swelling, shrinking and structural rearrangement. Our data show that astrocytes in brain slices in situ during hypotonic stress display complex behaviour. One population of astrocytes is highly capable of cell volume regulation, while the second population is characterized by prominent cell swelling, accompanied by plastic changes in morphology. It is possible to speculate that these two astrocyte populations play different roles during physiological and pathological states.
- MeSH
- astrocyty patologie ultrastruktura MeSH
- financování organizované MeSH
- geneticky modifikovaná zvířata MeSH
- gliový fibrilární kyselý protein analýza MeSH
- konfokální mikroskopie metody MeSH
- lidé MeSH
- modely u zvířat MeSH
- mozek patologie ultrastruktura MeSH
- myši MeSH
- nemoci mozku patologie MeSH
- zelené fluorescenční proteiny MeSH
- zobrazování trojrozměrné MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
Brain dynamics and the associations with spatial navigation in individuals with subjective cognitive decline (SCD) remain unknown. In this study, a hidden Markov model (HMM) was inferred from resting-state functional magnetic resonance imaging data in a cohort of 80 SCD and 77 normal control (NC) participants. By HMM, 12 states with distinct brain activity were identified. The SCD group showed increased fractional occupancy in the states with less activated ventral default mode, posterior salience, and visuospatial networks, while decreased fractional occupancy in the state with general network activation. The SCD group also showed decreased probabilities of transition into and out of the state with general network activation, suggesting an inability to dynamically upregulate and downregulate brain network activity. Significant correlations between brain dynamics and spatial navigation were observed. The combined features of spatial navigation and brain dynamics showed an area under the curve of 0.854 in distinguishing between SCD and NC. The findings may provide exploratory evidence of the reconfiguration of brain network dynamics underlying spatial deficits in SCD.
