RESUMO
This paper extends previously developed 3D SPM for Electrophysiological Source Imaging (Bosch et al., 2001) for neonate EEG. It builds on a prior paper by our group that established age dependent means and standard deviations for the scalp EEG Broad Band Spectral Parameters of children in the first year of life. We now present developmental equations for the narrow band log spectral power of EEG sources, obtained from a sample of 93 normal neonates from age 1 to 10 months in quiet sleep. The main finding from these regressions is that EEG power from 0.78 to 7.5 Hz decreases with age and also for 45-50 Hz. By contrast, there is an increase with age in the frequency band of 19-32 Hz localized to parietal, temporal and occipital areas. Deviations from the norm were analyzed for normal neonates and 17 with brain damage. The diagnostic accuracy (measured by the area under the ROC curve) of EEG source SPM is 0.80, 0.69 for average reference scalp EEG SPM, and 0.48 for Laplacian EEG SPM. This superior performance of 3D SPM over scalp qEEG suggests that it might be a promising approach for the evaluation of brain damage in the first year of life.
Assuntos
Mapeamento Encefálico/métodos , Eletroencefalografia , Imageamento Tridimensional , Sono/fisiologia , Eletroencefalografia/métodos , Feminino , Humanos , Lactente , Masculino , Análise de RegressãoRESUMO
Induced changes in electroencephalographic power and synchrony between pairs of electrodes were assessed during the Go/No-Go task in 15 young adults. Processes common to both conditions, such as attention, activation of working memory, letter identification, and discrimination processes were characterized by increased power and synchrony in the following frequency ranges: delta band (inhibition of the non-relevant stimuli), theta band (activation of working memory), and low alpha band in occipital regions immediately after the stimulus (withhold or control of the execution of a response), and decreased power in the high alpha band from 300 to 700 ms. However, the most important findings were those specific for each condition. Changes in power in frontal areas were observed immediately after the stimulus in delta and high alpha bands for the Go condition and in the theta band for the No-Go condition. Increased synchrony and power at 1 Hz from 350-500 ms and increased power at 1, 5 and 6 Hz after 300 ms in the No-Go condition may be related to inhibition. Other important difference between conditions was observed in the synchronization increases of the gamma band between 33 and 36 Hz in the Go condition, whereas synchrony decreased at these frequencies in the No-Go condition; these differences may be due to the preparation and execution of the motor response during the Go condition and its inhibition in the No-Go condition.
Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Tomada de Decisões/fisiologia , Eletroencefalografia , Análise Espectral/métodos , Adulto , Ritmo alfa , Atenção , Ritmo Delta , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
In this paper, we present a method for the study of synchronization patterns measured from EEG scalp potentials in psychophysiological experiments. This method is based on various techniques: a time-frequency decomposition using sinusoidal filters which improve phase accuracy for low frequencies, a Bayesian approach for the estimation of significant synchrony changes, and a time-frequency-topography visualization technique which allows for easy exploration and provides detailed insights of a particular experiment. Particularly, we focus on in-phase synchrony using an instantaneous phase-lock measure. We also discuss some of the most common methods in the literature, focusing on their relevance to long-range synchrony analysis; this discussion includes a comparison among various synchrony measures. Finally, we present the analysis of a figure categorization experiment to illustrate our method.