Home  About us  Contact
 

EEG Power (eeg + power)

Distribution by Scientific Domains
Medical Sciences60%

Terms modified by EEG Power

  • eeg power spectrum
    		•

    Selected Abstracts

    Functional topography of the human nonREM sleep electroencephalogram

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2001
    Luca A. Finelli
    Abstract The sleep EEG of healthy young men was recorded during baseline and recovery sleep after 40 h of waking. To analyse the EEG topography, power spectra were computed from 27 derivations. Mean power maps of the nonREM sleep EEG were calculated for 1-Hz bins between 1.0 and 24.75 Hz. Cluster analysis revealed a topographic segregation into distinct frequency bands which were similar for baseline and recovery sleep, and corresponded closely to the traditional frequency bands. Hallmarks of the power maps were the frontal predominance in the delta and alpha band, the occipital predominance in the theta band, and the sharply delineated vertex maximum in the sigma band. The effect of sleep deprivation on EEG topography was determined by calculating the recovery/baseline ratio of the power spectra. Prolonged waking induced an increase in power in the low-frequency range (1,10.75 Hz) which was largest over the frontal region, and a decrease in power in the sigma band (13,15.75 Hz) which was most pronounced over the vertex. The topographic pattern of the recovery/baseline power ratio was similar to the power ratio between the first and second half of the baseline night. These results indicate that changes in sleep propensity are reflected by specific regional differences in EEG power. The predominant increase of low-frequency power in frontal areas may be due to a high ,recovery need' of the frontal heteromodal association areas of the cortex. [source]

    Brain Electrical Activity Associated With Cognitive Processing During a Looking Version of the A-Not-B Task

    INFANCY, Issue 3 2001
    Martha Ann Bell
    This work was designed to investigate individual differences in brain electrical activity during a looking version of the A-not-B task. It was proposed that this spatial task required the cognitive skills of working memory and inhibitory control, each associated with frontal lobe function. Electroencephalograms (EEGs) were recorded from 54 8-month-old infants during baseline and task. Only high performers on the looking task exhibited increases in 6- to 9-Hz EEG power from baseline to task. These task-related changes were evident at frontal and posterior scalp locations. High performers on the looking task exhibited lower EEG coherence values at right hemisphere frontal locations relative to the low performers. These lower coherence values were evident during baseline and task. All infants showed increased frontal-parietal coherence during the spatial working memory task relative to baseline values. These data confirm previous cognitive neuroscience work associating frontal lobe function with cognitive performance levels during infancy. [source]

    Effects of Alcohol on Sleep and the Sleep Electroencephalogram in Healthy Young Women

    ALCOHOLISM, Issue 6 2006
    Eliza Van Reen
    Background: Although the association between sleep and alcohol has been of interest to scientists for decades, the effects of alcohol on sleep and sleep electroencephalogram (EEG) have not been extensively studied in women. Our specific aim was to determine whether sleep stage variables and/or spectral characteristics of the sleep EEG are altered by alcohol administration in women. Methods: Changes of sleep and the sleep EEG were investigated after administration of a moderate dose of alcohol (0.49 g/kg) in the hour before bedtime compared with placebo in young healthy women. After approximately 2 weeks at home on a fixed 8.5- or 9-hour stabilization sleep schedule, sleep was continuously recorded by polysomnography for 3 consecutive nights [adaptation, placebo, alcohol (mean breath alcohol concentration 0.043 g/% before bedtime)] in the laboratory in 7 women (ages 22,25, mean=23.5, SD=1 year). Sleep stages were scored according to conventional criteria. Electroencephalogram power spectra of the bipolar derivations Fz/Cz (anterior) and Pz/Oz (posterior) were calculated using a fast Fourier transform routine. Results: Only few changes in sleep and the sleep EEG were observed. Across the entire night rapid eye movement (REM) sleep decreased, while minutes of stage 4 sleep were increased in the first 2-hour interval on alcohol nights compared with placebo nights. Spectral analysis of the EEG showed increased power in the , range (9,11 Hz) during all-night non-REM (NREM) sleep in anterior derivations after alcohol compared with placebo. Differences in spectral EEG power were also present in 2-hour intervals of NREM sleep; in particular, EEG power was increased on the alcohol night for frequency bins within the , range in anterior derivations and within the , range (3,4 Hz) in posterior derivations during the initial part of the night. Conclusions: A moderate dose of alcohol just before bedtime resulted in a short-lived increase in sleep intensity. A limitation of the study, however, was that only a single dose of alcohol was used to examine the effects of alcohol on sleep. [source]

    Correlation between electroencephalography and heart rate variability during sleep

    PSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 1 2003
    MMLSC , Mina Ako MT
    Abstract It is known that autonomic nervous activities change in correspondence with sleep stages. However, the characteristics of continuous fluctuations in nocturnal autonomic nerve tone have not been clarified in detail. The study aimed to determine the possible correlation between the electroencephalogram (EEG) and autonomic nervous activities, and to clarify in detail the nocturnal fluctuations in autonomic nerve activities. Overnight EEGs and electrocardiograms of seven healthy males were obtained. These EEGs were analyzed by fast Fourier transformation algorithm to extract delta, sigma and beta power. Heart rate and heart rate variability (HRV) were calculated in consecutive 5-min epochs. The HRV indices of low frequency (LF), high frequency (HF) and LF/HF ratio were calculated from the spectral analysis of R-R intervals. The sleep stages were manually scored according to Rechtschaffen and Kales' criteria. Low frequency and LF/HF were significantly lower during non-rapid eye movement (NREM) than REM, and were lower in stages 3 and 4 than in stages 1 and 2. Furthermore, delta EEG showed inverse correlations with LF (r = , 0.44, P < 0.001) and LF/HF (r = , 0.41, P < 0.001). In contrast, HF differed neither between REM and NREM nor among NREM sleep stages. Detailed analysis revealed that correlation was evident from the first to third NREM, but not in the fourth and fifth NREM. Delta EEG power showed negative correlations with LF and LF/HF, suggesting that sympathetic nervous activities continuously fluctuate in accordance with sleep deepening and lightening. [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]

    Effects of nicotine and caffeine, separately and in combination, on EEG topography, mood, heart rate, cortisol, and vigilance

    PSYCHOPHYSIOLOGY, Issue 5 2000
    David G. Gilbert
    Effects of nicotine and caffeine, separately and in combination, were assessed in 12 male habitual smokers in a repeated-measures design. Caffeine (0-mg vs. two 150-mg doses administered in a decaffeinated/sugar-free cola drink post-baseline and 90 min later) was crossed with nicotine (ad libitum own dosing vs. 1.0-mg machine-delivered dose vs. 0.05-mg machine-delivered dose). Participants smoked a total of five cigarettes at 30-min intervals over a 2-hr period. Caffeine and nicotine had large effect sizes on electroencephalogram (EEG) power; however, these effects were modulated by the eyes open versus closed condition, the other drug, and electrode site. EEG effects of open versus closed eyes tended to be of the same size and direction as those of nicotine and caffeine. However, whereas nicotine increased EEG power in some higher frequency bands in some conditions, caffeine decreased EEG power across almost all conditions. Serum cortisol concentration, vigor, and pleasantness were increased by nicotine, but not by caffeine. Level of depressive mood depended on an interaction of caffeine and nicotine. Vigilance performance was enhanced significantly by caffeine and was increased almost significantly by nicotine. The findings were interpreted in terms of common and differential mechanisms of the two drugs. [source]

    Effects of phencyclidine (PCP) and MK 801 on the EEGq in the prefrontal cortex of conscious rats; antagonism by clozapine, and antagonists of AMPA-, ,1 - and 5-HT2A -receptors

    BRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2002
    Claude Sebban
    The electroencephalographic (EEG) effects of the propsychotic agent phencyclidine (PCP), were studied in conscious rats using power spectra (0 , 30 Hz), from the prefrontal cortex or sensorimotor cortex. PCP (0.1 , 3 mg kg,1 s.c.) caused a marked dose-dependent increase in EEG power in the frontal cortex at 1 , 3 Hz with decreases in power at higher frequencies (9 , 30 Hz). At high doses (3 mg kg,1 s.c.) the entire spectrum shifted to more positive values, indicating an increase in cortical synchronization. MK 801 (0.05 , 0.1 mg kg,1 i.p.) caused similar effects but with lesser changes in power. In contrast, the non-competitive AMPA antagonists GYKI 52466 and GYKI 53655 increased EEG power over the whole power spectrum (1 , 10 mg kg,1 i.p.) The atypical antipsychotic clozapine (0.2 mg kg,1 s.c.) synchronized the EEG (peak 8 Hz). The 5-HT2A -antagonist, M100907, specifically increased EEG power at 2 , 3 Hz at low doses (10 and 50 ,g kg÷1 s.c.), whereas at higher doses (0.1 mg kg,1 s.c.) the profile resembled that of clozapine. Clozapine (0.2 mg kg,1 s.c.), GYKI 53655 (5 mg kg,1 i.p.), prazosin (0.05 and 0.1 mg kg,1 i.p.), and M100907 (0.01 and 0.05 mg kg,1 s.c.) antagonized the decrease in power between 5 and 30 Hz caused by PCP (1 mg kg,1 s.c.), but not the increase in power at 1 , 3 Hz in prefrontal cortex. British Journal of Pharmacology (2002) 135, 65,78; doi:10.1038/sj.bjp.0704451 [source]