In order to study event-related desynchronization (ERD) related to voluntary movement, we designed two experiments. In the first experiment, untrained subjects were required to imagine the action of typing with left or right index finger for about 1 second before real action, whereas they were required to type instantly after instruction in the second experiment. By analyzing spontaneous EEG signals between the instruction and the action, we predicted which finger was used. The prediction accuracy in the first experiment fell from 85% to 71% with the progress of experiment, the average accuracy being 78%, whereas the prediction result was almost random guess in the second experiment. The results demonstrate that (1) ERD patterns are significantly affected by the effective duration of motion imagination, (2) unconscious reduction of this duration can decrease the prediction accuracy. Therefore, when designing subsequent BCI experiments, we should devote our attention to the question of how to keep the effective duration of motion imagination.
Brain ; physiology ; Cortical Synchronization ; Electroencephalography ; Humans ; Man-Machine Systems ; Task Performance and Analysis ; User-Computer Interface

Synchronous brain activities are considered as an indicator of the functional binding or integration. In this paper, based on the neural electric activities at various spatial scales, we explained the basic concept and measuring index of neural synchronization; then we summarized the main signal processing methods developed for phase synchronization analysis of electroencephalograph (EEG), including the conventional signal processing method, and modern signal modeling approaches. Finally, the main differences among the different methods were compared and some critical problems in the study of EEG synchronization were discussed.
Algorithms ; Analysis of Variance ; Brain ; physiology ; Cognition ; physiology ; Cortical Synchronization ; Electroencephalography ; methods ; Humans ; Signal Processing, Computer-Assisted

Synchronous brain activities are regarded as the indicator of the functional integration of the brain. Based on the physiological mechanism of synchronous activity, the detection process and research on quantification methods concerning synchronization are explained. Conventional and modern signal processing approaches, such as time analysis, frequency analysis, Hilbert transform (HT), especially wavelet transform (WT), are applied to EEG (electroencephalograph) synchronization study. Simulation data and real data are utilized to test the methods mentioned above, which prove the usefulness and validity of methods. According to the final results, Hilbert analysis is better for its authenticity.
Algorithms ; Analysis of Variance ; Animals ; Brain ; physiology ; Cortical Synchronization ; Electroencephalography ; methods ; Humans ; Rats ; Signal Processing, Computer-Assisted

The cognitive impairment of type 2 diabetes patients caused by long-term metabolic disorders has been the current focus of attention. In order to find the related electroencephalogram (EEG) characteristics to the mild cognitive impairment (MCI) of diabetes patients, this study analyses the EEG synchronization with the method of multichannel synchronization analysis--S estimator based on phase synchronization. The results showed that the S estimator values in each frequency band of diabetes patients with MCI were almost lower than that of control group. Especially, the S estimator values decreased significantly in the delta and alpha band, which indicated the EEG synchronization decrease. The MoCA scores and S value had a significant positive correlation in alpha band.
Cognitive Dysfunction ; diagnosis ; Cortical Synchronization ; Diabetes Mellitus, Type 2 ; Electroencephalography ; Humans

Our objective is the designing of a functional electrical stimulation (FES) system on event related desynchronization (ERD) and event related synchronization (ERS) signals. When the brain images the left-and right-leg movements, the ERD/ERS signals will appear. By characterization and characteristic classification, the ERD/ERS will be translated into the response control signal for operating the FES system to electrically stimulate the legs of motor disability. The result shows that the experiment is successful in electrically stimulating the legs of motor disability.
Brain ; physiopathology ; Cortical Synchronization ; Electric Stimulation ; methods ; Electroencephalography ; Evoked Potentials, Motor ; physiology ; Hemiplegia ; physiopathology ; rehabilitation ; Humans ; Motor Activity ; physiology ; User-Computer Interface

Left and right hand movement imagery can modifty the neural activity in the primary sensorimotor areas in a very similar way as observable with a real executed movement, leading to the special changes of EEG components such as event-related desynchronization/synchronization (ERD/ERS). Quick and correct classification of these event-related EEG pattern can be used to help patients with severe paralysis to move a cursor or orthosis to replace impaired motor function and provide a new communicatoion channel to environment. In this paper left and right hand movement imagery experiment method was introduced, some kinds of classification methods for event-related EEG pattern during motor imagery were reviewed and the prospect of classification methods was also put forward.
Communication Aids for Disabled ; Cortical Synchronization ; Electroencephalography ; instrumentation ; Evoked Potentials, Motor ; physiology ; Hand ; Humans ; Models, Biological ; Motor Cortex ; physiology ; Movement ; Signal Processing, Computer-Assisted ; User-Computer Interface

The thalamostriatal pathway is implicated in Parkinson's disease (PD); however, PD-related changes in the relationship between oscillatory activity in the centromedian-parafascicular complex (CM/Pf, or the Pf in rodents) and the dorsal striatum (DS) remain unclear. Therefore, we simultaneously recorded local field potentials (LFPs) in both the Pf and DS of hemiparkinsonian and control rats during epochs of rest or treadmill walking. The dopamine-lesioned rats showed increased LFP power in the beta band (12 Hz-35 Hz) in the Pf and DS during both epochs, but decreased LFP power in the delta (0.5 Hz-3 Hz) band in the Pf during rest epochs and in the DS during both epochs, compared to control rats. In addition, exaggerated low gamma (35 Hz-70 Hz) oscillations after dopamine loss were restricted to the Pf regardless of the behavioral state. Furthermore, enhanced synchronization of LFP oscillations was found between the Pf and DS after the dopamine lesion. Significant increases occurred in the mean coherence in both theta (3 Hz-7 Hz) and beta bands, and a significant increase was also noted in the phase coherence in the beta band between the Pf and DS during rest epochs. During the treadmill walking epochs, significant increases were found in both the alpha (7 Hz-12 Hz) and beta bands for two coherence measures. Collectively, dramatic changes in the relative LFP power and coherence in the thalamostriatal pathway may underlie the dysfunction of the basal ganglia-thalamocortical network circuits in PD, contributing to some of the motor and non-motor symptoms of the disease.
Animals ; Brain Waves ; physiology ; Corpus Striatum ; physiopathology ; Cortical Synchronization ; physiology ; Dopaminergic Neurons ; physiology ; Electrocorticography ; Male ; Neural Pathways ; physiopathology ; Oxidopamine ; Parkinsonian Disorders ; physiopathology ; Rats, Wistar ; Thalamic Nuclei ; physiopathology ; Walking ; physiology