ABSTRACT
The objective is to deal with brain effective connectivity among epilepsy electroencephalogram (EEG) signals recorded by use of depth electrodes in the cerebral cortex of patients suffering from refractory epilepsy during their epileptic seizures. The Wiener-Granger Causality Index (WGCI) is a well-known effective measure that can be useful to detect causal relations of interdependence in these kinds of EEG signals. It is based on the linear autoregressive model, and the issue of the estimation of the model parameters plays an important role in the calculation accuracy and robustness of WGCI to do research on brain effective connectivity. Focusing on this issue, a modified Akaike's information criterion algorithm is introduced in the computation of the WGCI to estimate the orders involved in the underlying models and in order to advance the performance of WGCI to detect brain effective connectivity. Experimental results support the interesting performance of the proposed algorithm to characterize the information flow both in a linear stochastic system and a physiology-based model.
ABSTRACT
OBJECTIVE: Many studies have reported that Taekwondo training could improve body perception, control and brain activity, as assessed with an electroencephalogram. This study aimed to assess body intelligence and brain connectivity in children with Taekwondo training as compared to children without Taekwondo training. METHODS: Fifteen children with Taekwondo training (TKD) and 13 age- and sex-matched children who had no previous experience of Taekwondo training (controls) were recruited. Body intelligence, clinical characteristics and brain connectivity in all children were assessed with the Body Intelligence Scale (BIS), self-report, and resting state functional magnetic resonance imaging. RESULTS: The mean BIS score in the TKD group was higher than that in the control group. The TKD group showed increased low-frequency fluctuations in the right frontal precentral gyrus and the right parietal precuneus, compared to the control group. The TKD group showed positive cerebellum vermis (lobe VII) seed to the right frontal, left frontal, and left parietal lobe. The control group showed positive cerebellum seed to the left frontal, parietal, and occipital cortex. Relative to the control group, the TKD group showed increased functional connectivity from cerebellum seed to the right inferior frontal gyrus. CONCLUSION: To the best of our knowledge, this is the first study to assess the effect of Taekwondo training on brain connectivity in children. Taekwondo training improved body intelligence and brain connectivity from the cerebellum to the parietal and frontal cortex.
Subject(s)
Child , Humans , Brain , Cerebellum , Electroencephalography , Intelligence , Magnetic Resonance Imaging , Parietal Lobe , RabeprazoleABSTRACT
Objective To explore properties of emotion memory circuits in late-life depression,and differences in functional connectivity of emotional memory network between late-life depression and healthy controls who were investigated by resting-state fMRI.Methods Eighteen late life depression patients and twenty four healthy controls were involved in our study.Resting-state functional MRI data were acquired via 3.0T MRI scanner.Functional MRI data were analyzed.Behavioral data were acquired during retrieval.The independent samples t-test of functional MRI data and ANOVA of behavioral performance were performed with AFNI and SPSS 13.0 statistical software,respectively.Results Decreased connectivities had been shown in depression,including amygdala-thalamus,amygdala-left inferior frontal gyrus,supramarginal gyrus-dorsomedial prefrontal cortex/anterior cingulate cortex (ACC),middle temporal gyrus-middle frontal gyrus and thalamus-inferior frontal gyros/left frontal eye fields (FEF) connectivity;while increased connectivities included hippocampus-middle temporal gyrus,hippocampusventromedial prefrontal cortex/middle temporal gyrus/ACC/FEF,middle temporal gyrus-fusiform gyrus/FEF,insula-middle temporal gyrus/FEF and thalamus-caudate connectivity (P＜0.05).For depression,global hubs included left amygdale,right hippocampus,right middle frontal gyrus,and right insula.For healthy group,global hubs included bilateral amygdale and middle frontal gyrus,right anterior inferior parietal lobe and right insula.Conclusion There are common and different characters in functional connectivity of emotional memory network between depression and healthy control.Global hub function decreases in the right amygdale and left inferior frontal gyrus,while right hippocampus shows compensatory increase.
ABSTRACT
Objective To observe the functional connectivity (FC) pattern linking the hippocampus with the rest of the brain in ischemic stroke patients with cognitive dysfunction,especially the default mode network (DMN).Methods Resting-state functional connectivity magnetic resonance imaging (fMRI) was performed on 15 ischemic stroke patients with cognitive dysfunction (the patient group) and 10 normal elderly controls.The bilateral hippocampus was the region of interest.Correlation analyses yielded a mapping of cerebral functional connectivity activation for both groups.Results Compared with the healthy controls,the patient group showed weakened functional connectivity between the hippocampus and other regions including the cingulate gyrus,the superior,middle and inferior frontal lobes,the inferior parietal lobule and the superior temporal gyrus.But there was enhanced functional connectivity with the cerebellar posterior lobe,the occipital lobe,the medial temporal lobe,the precuneus and the calcarine.The results were significantly different between the two groups.Conclusion The functional connectivity pattern of the hippocampus is impaired in stroke patients with cognitive dysfunction.Reduced functional connectivity between brain regions may be one cause of cognitive dysfunction after stroke,and enhanced functional connectivity may be an appropriate compensatory mechanism.
ABSTRACT
OBJECTIVES: We reviewed cellular and synaptic dysconnectivity, disturbances in micro- and macro- circuitries, and neurodevelopmentally-derived disruptions of neural connectivity in the pathogenesis of schizophrenia. METHOD: We reviewed the selected articles about disturbances in neural circuits which had been proposed as a pathogenetic mechanism of schizophrenia. RESULTS: The literature review reveals that schizophrenia may be a disease related to disturbance in neurodevelopmental mechanism, shown as 'a misconnection syndrome of neural circuit or neural network'. In descriptive psychopathological view, definition of a disorder of brain connectivity has limitation to explain other aspects of schizophrenia including deterministic strictness in thought process. CONCLUSION: Schizophrenia is considered as a disorder of brain connectivity as well as a neurodevelopmental disorder related with genetic and environmental factors. We could make a suggestion that "JoHyeonByung (attunement disorder)" denotes the disturbances of psychic fine-tuning which correspond to the neural correlates of brain dysconnectivity metaphorically.
Subject(s)
Brain , Metaphor , SchizophreniaABSTRACT
Since the transcranial magnetic stimulation (TMS) is a non-invasive technique to interfere neu-ral activity of brain, the combination of TMS and other neuron-imaging techniques has been widely used, espe-cially in cognitive research. Electroencephalogram (EEG) occupies a special position in this field due to its higher time resolution and lower experimental cost. The present paper reviews the application of TMS-EEG combined technique from the aspects of the main research topics, simultaneous recording, artifacts elimination, data pro-cessing and so on. Current problems and possible solution related to this technique are also discussed in the pa-per. With those new related solutions being put forward, more achievements will be obtained in the research area of TMS-EEG combined technique.
ABSTRACT
resumen está disponible en el texto completo
Abstract: The present paper offers a particular emergence, dual aspect, and dynamic system theory of the neural correlate of consciousness. The theory is grounded on two successive hypotheses supported with empirical evidences and concepts from the neurosciences, approximations to the sciences of complexity, and philosophical arguments. The first hypothesis is that consciousness emerges along with the highest level of brain function, i.e., at the intermodular domain of the whole organ. This hypothesis is upheld by two necessary requisites; the first is the generalized impression in neuroscience of the brain as an information-handling device, and that this property enables every mental activity, including consciousness, to take place. This concept is verified on several empirical grounds. If we take the synapse as a binary code of information, the computation capacity of the brain is in the order of 100 million Megabits. Even such enormous figure is limited and misleading because the synapse manifests not only two, but three possible informational states (excitation, rest, and inhibition), because there are subliminal potentials, and also a compact intracellular information machinery. Moreover, the informational requirement of consciousness is accurately delivered by Kuffler and Nichols' five ruling principles of brain function: (1) The brain uses electrical signals to process information; (2) Such electrical signals are identical in all neurons; (3) The signals constitute codes of codification and representation; (4) The origin and destiny of the fibers determines the content of information; (5) The meaning of the signals lies in the interactions. Even though the reference to representation, content, and meaning implies higher cognitive properties, it seems necessary to add a sixth principle for a more judicious neural implication in regard to consciousness. This principle is that information is processed in the brain in six levels of complexity, undergoing a gradual gain in density, integration, congruity, and capacity in each consecutive stratum. The six levels are the following: (1) Organismic, the integration of the nervous system with the rest of the organism systems; (2) Organic, the integration of the different modules in the whole brain; (3) Modular, the set of brain modules and their interconnections; (4) Intercellular, the designs and functional bindings among neuron cells; (5) Cellular, the set of brain cells, particularly neurons; (6) Molecular, the chemical components that mediate the transmission of information. In this fashion, the second requisite to uphold the emergence of consciousness lies in establishing that the different levels of brain organization constitute a pyramidal arrangement. Certainly, the number of elements is greater in the lower levels, while the integration of information is progressively enhanced in the upper levels. Moreover, this neuropsychological pyramid insinuates both an ascending cascade whereby the lower orders stipulate and influence the upper ones, and a progressive and convergent functional enrichment ultimately resulting in the qualia, feeling, and awareness attributes of consciousness. Information flows horizontally in each level, but it also overflows vertically in both directions. This pyramidal scheme is applied to clarify two parti cular aspects of brain function that are closely linked to consciousness: the electrical activity and the engram of memory. Such inquiry makes clear that a qualitative jump manifested by the emergence of various and dissimilar novelties occur at each layer of brain operation based upon a mass coordination. It seems feasible to envision the engram, and conceivably every other mental representation, as a plastic pattern involving all levels and aspects of brain operation, including the pinnacle where consciousness consolidates as the subjective aspect of the uppermost brain function. As a result of the proposed stratified and pyramidal scheme of brain functions, the first hypotheses is strengthened and specified. Thus, presumably consciousness and the neural capacities correlated to it constitute two associated aspects emerging from such particular functional hierarchy at the organic level of the brain by the efficient connection of its modules. It would not be required that all the modules of the brain become interrelated during a conscious processing, but that they would be functionally available while some of them become progressively active by intermodular articulation thereby making possible the arising and unfolding of conscious mental operation streams. In order to reinforce this notion the visual system is invoked since the scene that is consciously perceived emerges from the coordination of some 40 modules that separately appear to operate unconsciously. At the moment that such high-hierarchy and complex function presumably appears, it would achieve a conscious correlate and become altogether able to exert a descending causality and supervene the operation of the lower orders, which, among other capacities, would permit voluntary action to take place. In order to specify the first hypothesis asserting that consciousness emerges at the organic level of the brain along with the proficient inter-modular connectivity, a second hypothesis is formulated and justified in neuroanatomical, neurophysiological, and complexity science terms. The supposition is that the specific neural correlate of consciousness may be a function similar to a bird flock or an insect swarm orderly binding the operations of different modules in a cinematic, hipercomplex, coherent, and synchronic stream. The human brain contains some 400 cortical and subcortical modules functioning as partially specialized stations that potentially interchange particularly codified information through some 2500 fibers or intermodular pathways. The hypothesis requires that information complexity undergoes a further and substantial gain of attributions through the concise and prolific connectivity of the different modules. In this regard, it is supposed that a stream of coherent activation is constituted in the conscious brain by the intermodular dynamics and that such dynamics may acquire global patterned properties in a simi lar way as bird flocks and so-called intelligent swarms achieve unanimously shifting dynamics. This particular idea is supported with complexity science models of the remarkable performances of large groups of birds and insects and with the known behavior of massive populations of neurons. In so far as this would be a complex function operating at the limits of equilibrium resulting from local dynamics of the brain subsystems, the self-organization of high level brain functions justifies the notion that a dynamic coupling among modules can and may result in complex cognitive properties and consciousness. Intermodular brain dynamics is conceived here as an emergent, unbound, synchronic, hypercomplex, highly coherent, and tetradimensional process capable to navigate, steer, swirl, split, and flow throughout the brain and thereby connect very diverse systems in a fast and efficient manner. In the same way, its putative subjective correlate, the conscious process, can be conceived as an emergent, voluntary, unified, qualitative, and narrative process capable to access, coordinate, and integrate multiple local information mechanisms. The hypothesis poses that the conscious transformation of information is correlated, moment to moment and point to point, with the intermodular processing that evolves in the manner of a bird flock or swarm dynamics. It is finally posed that brain intermodular dynamics correlated to consciousness consolidates by the convergence of an ascending bottom-up organization of the different ranks of brain operation, and by the descending top-down influx of the social, cultural, and environmental information where the individual is immersed.
ABSTRACT
resumen está disponible en el texto completo
Abstract: The present paper offers a particular emergence, dual aspect, and dynamic system theory of the neural correlate of consciousness. The theory is grounded on two successive hypotheses supported by empirical evidences and concepts from the neurosciences, approximations to the sciences of complexity, and philosophical arguments. The first hypothesis is that consciousness emerges along with the highest level of brain function, i.e., at the intermodular domain of the whole organ. This hypothesis is upheld by two necessary requisites. The first is the generalized impression in neurosciences of the brain as an information-handling device, and that this property enables every mental activity, including consciousness. This concept is verified on several empirical grounds. If we take the synapse as a binary code of information, the computation capacity of the brain is in the order of the 100 million megabits. Even such an enormous figure is limited and misleading because the synapse manifests not only two, but three possible informational states (excitation, rest, and inhibition), because there are subliminal potentials, and also a compact intracellular information machinery. Moreover, the informational requirement of consciousness is accurately delivered by Kuffler and Nichols' five ruling principles of brain function: 1. The brain uses electrical signals to process information; 2. such electrical signals are identical in all neurons; 3. the signals constitute codes of codification and representation; 4. the origin and destiny of the fibers determines the content of information; 5. the meaning of the signals lies in the interactions. Even though the reference to representation, content, and meaning implies higher cognitive properties, it seems necessary to add a sixth principle for a more judicious neural implication in regard to consciousness. This principle is that information is processed in the brain in six levels of complexity, undergoing a gradual gain in density, integration, congruity, and capacity in each consecutive stratum. The six levels are the following: 1. organismic, the integration of the nervous system with the rest of the organism systems; 2. organic, the integration of the different modules in the whole brain; 3. modu lar, the set of brain modules and their interconnections; 4. intercellular, the designs and functional bindings among neuron cells; 5. cellular, the set of brain cells, particularly neurons; 6. molecular, the chemical components that mediate the transmission of information. In this fashion, the second requisite to uphold the emergence of consciousness lies in establishing that the different levels of brain organization constitute a pyramidal arrangement. Certainly, the number of elements is greater in the lower levels, while the integration of information is progressively enhanced in the upper levels. Moreover, this neuropychological pyramid insinuates both an ascending cascade whereby the lower orders stipulate and influence the upper ones, and a progressive and convergent functional enrichment ultimately resulting in the qualia, feeling, and awareness attributes of consciousness. Information flows horizontally in each level, but it also overflows vertically in both directions. This pyramidal scheme is applied to clarify two parti cular aspects of brain function that are closely linked to consciousness: the electrical activity and the engram of memory. Such inquiry makes clear that a qualitative jump manifested by the emergence of various and dissimilar novelties occur at each layer of brain operation based upon a mass coordination. It seems feasible to envision the engram, and conceivably every other mental representation, as a plastic pattern involving all levels and aspects of brain operation, including the pinnacle where consciousness consolidates as the subjective aspect of the uppermost brain function. As a result of the proposed stratified and pyramidal scheme of brain functions, the first hypotheses is strengthened and specified. Thus, presumably consciousness and the neural capacities correlated to it constitute two associated aspects emerging from such particular functional hierarchy at the organic level of the brain by the efficient connection of its modules. It would not be required that all the modules of the brain became interrelated during a conscious processing, but that they would be functionally available instead, while some of them become progressively active by intermodular articulation, thereby making possible the arising and unfolding of conscious mental operation streams. In order to reinforce this notion, the visual system is invoked since the consciously perceived scene emerges from the coordination of some 40 modules that separately appear to operate unconsciously. At the moment that such high-hierarchy and complex function presumably appears, it would achieve a conscious correlate and become altogether able to exert a descending causality and supervene the operation of the lower orders, which, among other capacities, would permit voluntary action to take place. In order to specify the first hypothesis, asserting that consciousness emerges at the organic level of the brain along with the proficient intermodular connectivity, a second hypothesis is formulated and justified in neuroanatomical, neurophysiological, and complex scientific terms. The supposition is that the specific neural correlate of consciousness may be a function similar to a bird flock or an insect swarm orderly binding the operations of different modules in a cinematic, hipercomplex, coherent, and synchronic stream. The human brain contains some 400 cortical and subcortical modules functioning as partially specialized stations that potentially interchange particularly codified information through some 2500 fibers or intermodular pathways. The hypothesis requires information complexity undergoing a further and substantial gain of attributions through the concise and prolific connectivity of the different modules. In this regard, it is supposed that a stream of coherent activation is constituted in the conscious brain by the intermodular dynamics and that such dynamics may acquire global patterned properties in a simi lar way as bird flocks and so-called intelligent swarms achieve unanimously shifting dynamics. This particular idea is supported with complex scientific models of the remarkable performances of large groups of birds and insects and with the known behavior of massive populations of neurons. In so far as this would be a complex function operating at the limits of equilibrium resulting from local dynamics of the brain subsystems, the self-organization of high level brain functions justifies the notion that a dynamic coupling among modules may result in complex cognitive properties and consciousness. Intermodular brain dynamics is conceived here as an emergent, unbound, synchronic, hypercomplex, highly coherent, and tetradimensional process capable to navigate, steer, swirl, split, and flow throughout the brain and thereby connect very diverse systems in a fast and efficient manner. In the same way, its putative subjective correlate -the conscious process- may be conceived as an emergent, voluntary, unified, qualitative, and narrative process capable to access, coordinate, and integrate multiple local information mechanisms. The hypothesis poses that the conscious transformation of information is correlated, moment to moment and point to point, with the intermodular processing that evolves in the manner of a bird flock or swarm dynamics. It is finally posed that brain intermodular dynamics correlated to consciousness consolidates by the convergence of an ascending bottom-up organization of the different ranks of brain operation, and by the descending top-down influx of the social, cultural, and environmental information where the individual is immersed.