- MeSH
- Radionuclide Imaging methods instrumentation MeSH
- Veins abnormalities MeSH
- Publication type
- Case Reports 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
- Central Nervous System physiology MeSH
- Electroencephalography methods utilization MeSH
- Electromagnetic Fields MeSH
- Research Support as Topic MeSH
- Humans MeSH
- Magnetic Resonance Imaging methods MeSH
- Magnetoencephalography methods utilization MeSH
- Brain anatomy & histology physiopathology pathology MeSH
- Systems Theory MeSH
- Tomography methods MeSH
- Check Tag
- Humans 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
- Adult MeSH
- Electroencephalography MeSH
- Electrocorticography MeSH
- Gamma Rhythm physiology MeSH
- Humans MeSH
- Brain Mapping methods MeSH
- Young Adult MeSH
- Brain physiology MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't 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
- Dissociative Disorders etiology physiopathology psychology MeSH
- Epilepsy, Temporal Lobe complications MeSH
- Financing, Organized MeSH
- Humans MeSH
- Brain physiology MeSH
- Neural Networks, Computer MeSH
- Memory MeSH
- Psychotic Disorders physiopathology MeSH
- Consciousness MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review 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
- Mental Disorders * MeSH
- Humans MeSH
- Magnetic Resonance Imaging methods MeSH
- Brain Mapping MeSH
- Brain physiology MeSH
- Social Interaction * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't 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
- Adult MeSH
- Hallucinogens pharmacology MeSH
- Marijuana Smoking psychology MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Young Adult MeSH
- Brain diagnostic imaging drug effects MeSH
- Dronabinol pharmacology MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Randomized Controlled Trial MeSH
- Research Support, N.I.H., Extramural MeSH
