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EEG Synchronization (eeg + synchronization)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Time course of EEG background activity level before spontaneous awakening in infants

JOURNAL OF SLEEP RESEARCH, Issue 4 2002
Chiara Zampi
SUMMARY This research aimed to investigate the time course of the cortical activity level preceding spontaneous awakening as a function of age and state. Two groups of infants (1,4 and 9,14 weeks of age) were continuously monitored by polygraphic recording and behavioural observation during the night. The electroencephalographic (EEG) activity recorded by the C3,O1 lead was analysed through an automatic analysis method which provides, for each 30-s epoch, a single measure, time domain based, of the EEG synchronization. The EEG parameter values were computed in the 6 min preceding each awakening out of non-rapid eye movement (NREM) sleep and out of rapid eye movement (REM) sleep. The EEG background activity level did not change in the minutes preceding awakening out of REM sleep. Awakening out of NREM sleep was preceded by a change of EEG activity level in the direction of higher activation with different time course according to the age. Both REM and NREM sleep results suggest that a high level of EEG activity is a prerequisite for the occurrence of a spontaneous awakening. [source]

Non-linear EEG synchronization during observation: Effects of instructions and expertise

PSYCHOPHYSIOLOGY, Issue 5 2010
Claire Calmels
Abstract The aim of this study was to examine the effects of instructions and expertise upon neuronal changes during observation of sequential finger movements. Professional pianists and musically naïve subjects observed these movements with the aim of either replicating or recognizing them at a later stage. A non-linear measure of functional coupling was used to investigate EEG activity. In the 10,13 Hz frequency band and in musically naïve subjects, functional coupling during observation for replica was greater within central and neighboring areas than during observation for recognition. An opposite pattern was found in the 4,8 Hz frequency band. In the 10,13 Hz band and in areas including the parietal cortex, functional coupling in musically naïve subjects was greater compared to professional pianists under observation for replica. Results are discussed in the light of recent findings from the cognitive and behavioral neuroscience literature. [source]

Attenuated asymmetry of functional connectivity in schizophrenia: A high-resolution EEG study

PSYCHOPHYSIOLOGY, Issue 4 2010
Mahdi Jalili
Abstract The interhemispheric asymmetries that originate from connectivity-related structuring of the cortex are compromised in schizophrenia (SZ). Under the assumption that such abnormalities affect functional connectivity, we analyzed its correlate,EEG synchronization,in SZ patients and matched controls. We applied multivariate synchronization measures based on Laplacian EEG and tuned to various spatial scales. Compared to the controls who had rightward asymmetry at a local level (EEG power), rightward anterior and leftward posterior asymmetries at an intraregional level (1st and 2nd order S-estimator), and rightward global asymmetry (hemispheric S-estimator), SZ patients showed generally attenuated asymmetry, the effect being strongest for intraregional synchronization in the alpha and beta bands. The abnormalities of asymmetry increased with the duration of the disease and correlated with the negative symptoms. We discuss the tentative links between these findings and gross anatomical asymmetries, including the cerebral torque and gyrification pattern, in normal subjects and SZ patients. [source]

EEG synchronization in mild cognitive impairment and Alzheimer's disease

ACTA NEUROLOGICA SCANDINAVICA, Issue 2 2003
C. J. Stam
Objectives , To compute the synchronization likelihood of multichannel electroencephalogram (EEG) data in Alzheimer (AD) patients, subjects with mild cognitive impairment (MCI) and subjects with subjective memory complaints (SC). Material and methods , EEGs (200 Hz sample frequency; 21 channels; average reference) were recorded in 10 AD patients (two males; age 76.2; SD 9.36; range 59,86), 17 subjects with MCI (eight males; age 77.41; SD 6.25; range 62,88) and 20 subjects with SCI (11 males; age 68.9; SD 12.96; range: 51,89). The synchronization likelihood, a novel type of coherence measure, was computed, comparing each channel with all other channels, for the 2,6, 6,10, 10,14, 14,18, 18,22 and 22,50 Hz band. Results , The synchronization likelihood was significantly decreased in the 14,18 and 18,22 Hz band in AD patients compared with both MCI subjects and healthy controls. Lower beta band synchronization correlated with lower Mini-Mental state examination (MMSE) scores. Conclusion , Loss of beta band synchronization occurs early in mildly affected AD patients and correlates with cognitive impairment. [source]