cortical synchronization

..In both circumstances, the neurons in the hand area are not needed for visual processing or preparation for foot movement. As a result of this, an enhanced hand area mu rhythm can be observed...

..Subsequently, the changes observed in the post-movement phase might reflect a decrease in (reafferent) sensory inputs and hence impaired their input processing...

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..Finally, implications of abnormal neural synchronization are discussed as they relate to mental disorders like schizophrenia and autism...

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..These results point to a general computational role for selective synchronization in dynamically controlling which neurons communicate information about sensory inputs effectively...

..The enhancement of cross-frequency phase synchrony among functionally and spatially distinct networks during mental arithmetic tasks posits it as a candidate mechanism for the integration of spectrally distributed processing...

..Thus, late postnatal maturation of BCs enhances coherence in neuronal networks and will thereby contribute to the development of cognitive brain functions...

..Graph theoretical analysis may be a useful approach to study the complexity of patterns of interrelations between EEG channels...

..Our results support a link between levodopa-induced improvements in bradykinesia and rigidity and reductions in population synchrony at frequencies < 35 Hz in the region of the STN in patients with PD...

..These results raise fundamental questions about how noise can influence neural function and computation...

..The hypothesis, suggested here is that theta and upper alpha reflect these processes which can be best studied when analyzing phase...

..Finally, we suggest that developmental disruption of the endophenotype for certain subsets of gamma-generating interneuron may underlie cognitive deficit in psychiatric illness...

..Therefore, this project was set up to characterize the neurophysiologic basis of seizure-related fear and the contribution of the amygdala-hippocampus system...

..The firing rate was represented by a classical rate code in the initial layers, but switched to a synchrony-based code in the deeper layers...

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..SIGNIFICANCE: This study suggests that thalamocortical circuits are involved in attentional modulation of pain because of the proposed role of these circuits in the mechanisms of ERD...

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..We illustrate this using a single-subject MEG study of binocular rivalry and highlight the greater recovery of statistical dependencies among cortical areas in the beta band when mutual information is used...

..Further comparison with electrophysiological data from both rodents and primates suggests a possible role of theta oscillations in memory encoding and online processing of episodic events...

..In conclusion, the present EEG study could suggest an effect of the muscarinic cholinergic agonist pilocarpine on the hippocampal-cortical functional connectivity...

..However, we show that there is an advantage in the processing of information if rate modulation is accompanied by gamma modulation, namely that reaction times are shorter, implying behavioral relevance for gamma synchronization...

..These links have already resulted in the development of new remediation strategies, which have some translational potential...

..Although less firmly established than the role of oscillations in movement disorders, oscillatory activities at higher frequencies may also be a component of normal basal ganglia physiology...

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..We also show that these results extend to moderate coupling strengths...

..These findings are compatible with the notion that theta oscillations are related to the binding of distributed cortical representations during recollection...

..Here we report the first evidence that theta phase synchronization dynamically coordinates the central executive circuits, including the medial prefrontal cortex and relevant cortical regions...

..Thus, the observed changes in firing rate and coherence of neurons in the visual cortex could be controlled by top-down inputs that regulated the coherence in the activity of a local inhibitory network discharging at gamma frequencies...

..We propose that the critical process mediating the access to conscious perception is the early transient global increase of phase synchrony of oscillatory activity in the gamma frequency range...

..0019) with the ascent. The suppressed post-movement beta ERS at an altitude of 2700 m may therefore be interpreted as a result of an increased cortical excitability level when compared with the reference altitude of 990 m above sea level...

..Finally, we also found the basal ganglia to participate at an early stage in the processing of biological movement, possibly by selecting suitable motor programs that match the stimulus...

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..We examined the hypothesis that cognitive dysfunction in Alzheimer's disease is associated with abnormal spontaneous fluctuations of EEG synchronization levels during an eyes-closed resting state...

..In addition, it predicts that attention increases the delay between the inhibitory and excitatory synchronous volleys produced by the network, allowing the stimulus to recruit more downstream neurons...

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..In summary, synchronization of neural assemblies in different frequency ranges induces specific forms of cellular plasticity during subsequent stages of memory formation...

..The duration distributions of these patterns have similar forms within a subject, which suggests that they share the same mechanism for their generation...

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..We present a model study illustrating that the scaling property and the collective intermittent dynamics are emergent features of globally coupled phase oscillators near the critical point of entering global frequency locking...

..In contrast to the theta band, remembered and not remembered words revealed a complex pattern of desynchronization in the lower and upper alpha band that was different during encoding and recognition...

..This study supports the hypothesis of having a focal susceptibility of the cerebral cortex prior to absence seizures and further underlines that this susceptibility is reproducible and patient-specific...

..Therefore, we claim that the applied measures are valuable for the study of synchronization in real data. Moreover, in the particular case of EEG signals their use as complementary variables could be of clinical relevance...

..This finding is interpreted as an EEG aspect of the functional linking between the prefrontal areas and the G.cinguli (as part of the limbic system), which are both extremely important for memory functions...

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..Together with our previous results it appears that synchronization is stimulus dependent and its strength increases with larger disparities included in the whole stimulating image...

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..Finally we relate these theoretical studies to the available experimental data, and suggest future lines of research...

..To review the coherent, rhythmic oscillations above approximately 20 Hz that occur in response to sensory inputs in the firing rate and membrane or local field potentials of distributed neuron aggregates of CNS layered structures...

..The synchronization properties are consistent with data suggesting that gamma rhythms are used for relatively local computations whereas beta rhythms are used for higher level interactions involving more distant structures...

..Coherent activity in this low-frequency range might play a role for binding of multimodal ensembles...

..In contrast to alpha and theta, ERD in the delta band is not influenced by the magnitude of band power in the reference interval...

..They further imply that stronger top-down control leads to larger and faster sensory responses, and a subsequently faster motor response...

..Enhanced levels of anticipatory synchronization occur in response to the demands of the task in conditions where the system's limited capacity is under strain...

..Thus, background activity not only sharpens cortical responses but it can also be used to tune an entire network between integration and coincidence detection modes...

..We propose that mGluR1a-induced oscillations are a potential mechanism whereby the thalamus promotes EEG alpha and theta rhythms in the intact brain...

..The oscillations will therefore be effectively transmitted to spinal motoneurons, and this has important consequences for the possible role of oscillations in motor control of the hand...

..Here we tested the model predictions by obtaining LFP recordings from the rat cerebral cortex and comparing conditions of high homeostatic sleep pressure (early sleep) and low homeostatic sleep pressure (late sleep)...

..Cortex functions by serial changes in state. The Hilbert transform of EEG from high-density arrays can visualize these state transitions with high temporal and spatial resolution and should be useful in relating EEG to cognition...

..These results lend further support for a functional role of rhythmic neuronal synchronization in attentional stimulus selection...

..The analysis of linear and nonlinear EEG synchronization associated with cognitive processing is suitable to explore the task-related and region specific features of these events...

..The intrinsic variability, as well as the participating areas, points to the role of strategic cognitive processes in perceptual switching...

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..These results show that sub-threshold stimuli are able to phase synchronize or desynchronize two networks and suggest that small signals could play an important role in normal neural activity and epilepsy...

..The present work aims at evaluating the impact of brain tumours on spatial patterns of functional connectivity of the brain measured at rest by MEG...

..These results are the first compelling evidence of pain networks characterized by rapidly switching, task-specific functional connectivity...

..This implies that such EEG phenomena may be utilized in a multi-class brain-computer interface (BCI) operated simply by motor imagery...

..e., reduced cortical activation) towards an overt hyper-synchronization (cortical idling)...

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..Here, we investigated the model's predictions in humans by using all-night high-density (hd)-EEG recordings to explore slow-wave parameters over the entire cortical mantle...

..Animal and human experimental data are described which reveal either dominance of one of these types or their complex interaction...

..However, due to the limits of currently used bivariate methods, functional correlates of dysconnection are limited to the isolated measurements of synchronization between preselected pairs of EEG signals...

..e., the "binding" of the neurons). The results are in accordance with the disturbance of connections between the neurons giving additional information related to the localization of most prominent disconnection...

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..Changing activity predominance of certain regulatory structures was considered one of the most important factors determining the dynamic nature of EEG coherence...

..Higher heritability values were not associated with higher coherences. The examination of bivariate genetic correlations suggests that there is a difference between theta and alpha bands in genetic control of interhemispheric coherence...

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..By systematically characterising the brain dynamics underlying naturalistic driving behaviour in a real city, our findings may have implications for how driving competence is considered in the context of neurological damage...

..Theoretical conceptions of autism spectrum disorder (ASD) and experimental studies of cerebral blood flow suggest abnormalities in connections among distributed neural systems in ASD...

..Additionally, statistical relationship between functional connectivity and the severity of opioid withdrawal has been found...

..If it reflects the action of the efference copy, it should be related to subsequent sensory suppression. If efference copy/corollary discharge mechanisms are abnormal in schizophrenia, it should be reduced in patients with schizophrenia...

..We propose that the efferent GABAergic signal of ZI neurons patterned by the cortical activity can play a critical role in synchronizing thalamocortical and brainstem rhythms...

..This effect was strongest in a fronto-medial source. Induced gamma, as also shown in previous studies, reflects the more task-relevant mechanism where object representations become activated...

..74) better than the worst Glasgow Coma Scale score, length of coma, or extent of injury on CT scan. This represents a novel approach in the evaluation of TBI in children...

..Spike time response curves (STRCs) are used to study the relationship between the transitions in rhythm and the underlying biophysics...

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..Gamma band activity may be just involved in the execution of the movement, related to muscle contraction...

..These key findings support previous literature in terms of there being substantial overlap in frontal neural circuitry when the brain processes pleasant and unpleasant valence relative to neutral valence...

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..Such a right-hemispheric "electrocortical effort" in alexithymia could reflect difficulties in symbolization of emotion resulting from impaired right-hemispheric analogical and global nonverbal emotional representation...

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..It is concluded that measures of Gamma synchrony offer a valuable window into the core integrative disturbance in schizophrenia cognition...

..These results suggest that inhibition can be an efficient mechanism for synchronization of large neuronal populations...

..The strict relation between gamma response and perception suggests that retrieval processes of long-term memory deeply impinged upon sensory representation of the stored material...

..However, only very few neurophysiological recordings from the basal ganglia support neuropharmacologic data. We investigated the electrophysiologic activity of SNpr neurons in rats with genetic absence epilepsy...

..This might reflect an optimal organization pattern for information processing, connecting any two brain area by only a small number of intermediate steps...

..Using a whole-head MEG system, we will assess patterns of auditory cortical synchronization with high precision in both time and frequency...

..Using a whole-head MEG system, we will assess patterns of auditory cortical synchronization with high precision in both time and frequency...

..Analyses of disturbances in cortico-cortical synchronization hold the promise of providing critical diagnostic measures for a wide variety of cognitive disturbances...

..These features and others make cortistatin a sleep factor that may have a major role in cortical synchronization and the maintenance of slow wave sleep...

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..This research is expected to provide new insights into the largely subconscious psychological processes underlying the flexible control of timing in both musical and nonmusical contexts. ..

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..In the long run, this research may suggest ways of improving music education and increasing music appreciation, with positive consequences for mental health and quality of life...

..Aim 3 is to study the mechanisms underlying the generation of synchrony. One hypothesis that will be tested is phase locking of action potentials to a periodic function (oscillations). ..

..g. hemineglect, and elucidating how selective attention works with image understanding will be important for understanding the mechanisms underlying these diseases. ..

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..Funds are also requested to support the national independent evaluation of both the KGT Foundation Medical Student Fellowship (at six sites) and the Integrated Research Pathway Program (at two sites). ..

..A better understanding of the neural dynamics of memory may help us better understand the pathogenesis of memory disorders in the mentally ill and thus lead to better treatments. ..

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..Taken together, this data may serve to elucidate whether the known cognitive dysfunction observed in cannabis use is in part related to disturbances in early sensory information processing and/or neural synchronization. ..

..3-To identify cortical regions, and physiological processes generating object-related ERPs shown to be abnormal in schizophrenic patients. ..

..This will set the stage for use of the subiculum slice and subiculum computer model as an epilepsy model. ..

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..These correlations are expected to provide crucial information on the neuronal basis of functional imaging signals, such as those obtained by BOLD fMRI, in human cognition. ..

..They will determine if regional and agent-specific differences in microvascular vasodilation in response to volatile anesthetics are due to the effects of these agents on the GABA and NO neuronal systems. ..

..These experiments will also provide a starting point for conduction similar more limited studies in humans, the long range goal of our research program. ..

..These studies will establish how an endogenous neurotrophin, considered to be neuroprotective primarily, can influence normal and abnormal activity in the limbic system. ..

..In this proposal we seek to better understand the neurobiology underlying the cognitive abnormalities in schizophrenia;with the hope that, in turn, this will advance the development of novel treatments for these cognitive impairments. ..

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..Equal numbers of female and male subjects will be assessed in all phases. The proposed methods will characterize CNS differences from MDMA use to provide assessment of drug effects on cognition. ..

..impairment specific to hearing disorders, and in a spectrum of disorders including ADHD, autism and schizophrenia, where defects in normal connectivity, disruptions of neuronal synchrony and attentional impairments are prominent ..

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..These results will provide fundamental data on how MDMA use may alter CNS function. ..

..These experiments are intended to elucidate the processes underlying the supersensitivity to dopamine and its agonists that occurs after dopaminergic denervation. ..

..Taken together, data from these studies will further our understanding of the cannabinoid system, which will help elucidate the mechanism of action of one of the most commonly used drugs of abuse.Project Narrative ..