SEARCH · PubMed Health

Results for “Brain waves”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources

PubMed1994

Event-related and motor responses to probes in a forewarned reaction time task in schizophrenic patients.

Surface-negative brain potentials indicate increased excitability of the underlying cortical neural networks. Consequently, deviant patterns of event-related potentials in schizophrenic patients reveal an atypical regulation of cortical excitability. Twelve patients with a chronic schizophrenic disorder and 12 matched control subjects were investigated using a probe paradigm: A contingent negative variation (CNV) was evoked in a forewarned reaction time paradigm. Clicks were presented before, during and after elicitation of the CNV. Click-evoked responses allow one to 'probe' the current brain state, particularly neuronal excitability, which is also reflected by the slow potentials. During the measurements, subjects pressed one button in response to the offset of the visual warning stimulus and a different button in response to the acoustic probes, the latter button press being a behavioral indication of the brain's excitability. In the forewarned reaction time task, patients developed a CNV with a frontal maximum, while the CNV in control subjects was predominantly centro-parietal. This atypical topographical pattern of the CNV may indicate a different spatio-temporal regulation of cortical preparatory processes in schizophrenics. Motor responses were accelerated during negative potential shifts in both patients and controls, with responses being slower overall in patients. In patients, probe-evoked potentials revealed a smaller N100, but a larger P300, than in controls. The covariation of these brain waves with slow potentials, however, turned out to be similar for both groups.

Adult↗

PubMed1993

Quantitative electroencephalographic correlates of steroid administration in man.

Elevated levels of circulating corticosteroids are frequently associated with behavioral alterations in man, although the mechanisms by which corticosteroids may affect behavior are poorly understood. To evaluate possible effects of exogenous corticosteroids on brain electrophysiological functioning and the relationship of such effects to behavioral and biochemical changes, we administered prednisone (80 mg p.o. daily for 5 days) in a double-blind manner to 11 medically healthy volunteers. Quantitative electroencephalogram analysis was performed following 4 days of prednisone administration and during the preceding and ensuing placebo administration periods. Central theta wave brain electrical activity significantly increased following prednisone administration and returned to baseline following prednisone withdrawal. This effect was directly correlated with prednisone-induced increases in subjective sadness ratings and with decreases in self-rated energy and well-being. Prednisone-induced reductions in peak alpha wave activity were also directly correlated with increases in subjective sadness and Symptom Checklist-90 ratings and with decreases in self-rated 'hypomanic' symptoms. Further, prednisone-induced increases in theta activity were significantly correlated with prednisone-induced decreases in CSF levels of somatostatin-like immunoreactivity, and prednisone-induced decreases in peak alpha activity were significantly correlated with decreases in CSF levels of norepinephrine and with relative increases (or lesser decreases) in CSF levels of beta-endorphin and beta-lipotropic hormone. This preliminary report of the concomitant development of prednisone-induced changes in brain electrical activity, neurochemistry and behavior highlights areas for future exploration in the study of corticosteroid effects on behavior in man.

Adult↗

PubMedDate not supplied

Effects of a carbohydrate supplement upon resting brain activity.

Glucose is a major energy source for the brain, and along with several monosaccharide derivatives as components of brain gangliosides, they play important roles in neurologic function. However, there is little information available on the role of glucose and other monosaccharides on resting brain activity. This study was designed to evaluate the effects of a single dose of a carbohydrate supplement containing glucose and several of its derivatives on resting brain activity in 20 healthy male college students. The supplement provided an insignificant amount of carbohydrate (3.9 g), protein (0.28 g), fat (0 g), and calories (14 kcal). The amount of glucose in the supplement was 0.5 g (1% the amount of glucose used in adult studies of cognitive functioning and memory). We hypothesized that the glyconutrient supplement would enhance brain activity associated with alertness and attention. The study design was double blind, with subjects randomly assigned to one of two orders, either carbohydrate supplement week one followed by placebo a week later, or the opposite. Electrical brain activity was monitored by 15 electrodes positioned at nine standard international 10-20 system locations, including three bilateral pairs at frontal, parietal, and occipital sites. Thirty minutes following ingestion of a placebo or carbohydrate supplement drink, EEG activity was recorded for 10-mins while subjects focused on a stationary visual target. Spectral power of resting brain activity was computed and analyzed contrasting the placebo and supplement groups. Relative to placebo, the carbohydrate supplement significantly enhanced power in three brain wave frequencies (theta, alpha, and beta) that are known to be associated with attention and arousal. Since changes were observed in the supplement but not placebo group, our study suggests that additional sugars in the glyconutritional supplement facilitate enhancement of brain electrical activity. Whether the apparent enhancement of arousal in baseline recordings is associated with improved task performance remains to be determined.

Adult↗

PubMed1981

Genetic disposition to alcoholism. An EEG study in alcoholics and their relatives.

Family, twin, and adoption studies have shown that genetic factors are involved in the etiology of alcoholism. Based on earlier EEG findings in alcoholics and on the known genetic determination of the alcohol effect on the EEG, the hypothesis was tested whether the resting EEG reflects a certain disposition to alcoholism. Resting EEGs were examined for 115 alcoholics (78 males, 37 females) and matched controls. In addition, the first-degree relatives of two extreme groups of alcoholics--those with poor and those with particularly good alpha waves--were examined and compared with matched controls. The EEGs were analyzed with an EEG processor. Whereas male alcoholics did not differ from their controls, female patients showed a shift from the alpha and theta to the beta bands of the brain wave pattern. The relatives of the two extreme groups of alcoholics, who did not misuse alcohol, exhibited the same tendency. This is an argument supporting the notion that in females a poorly synchronized EEG pattern reflects a certain disposition to alcoholism. This finding is discussed in light of drinking motivation in males and females. The latter more often belong to the alpha- and gamma-types of alcoholism than do males. Because of comparable findings in schizophrenics it is argued that a genetically determined desynchronized resting EEG pattern is not specific for a certain illness, but reflects basic mechanisms that enhance the risk for different psychiatric disorders.

Adolescent↗

PubMed1977

[Genetic control of the ethanol effect on the human EEG].

26 identical and 26 fraternal twin pairs were subjected to 1,2 ml/kg alcohol loading under standardized conditions; furthermore, 13 non-twin persons were repeatedly subjected to the same procedure in order to test the intraindividual variability. The alcohol effect was pursued by repeated EEG recordings. The EEGs of identical twins proved to react identically to alcohol loading, whereas the EEGs of fraternal twins became more dissimilar during the course of the experiment. The identical reaction of the brain wave pattern in monozygotic twins cannot be attributed to more similar blood alcohol concentrations; instead, this finding is a pharmacogenetic phenomenon of the central nervous system.

Adult↗

PubMed2002

Dynamics of brain electric field during recall of Salpuri dance performance.

The brain wave activity of a professional Salpuri dancer was observed while the subject recalled her performance of the Salpuri dance when sitting in a chair with closed eyes. As she recalled the feeling of the ecstatic trance state induced by the dance, an increase in alpha brain activity was observed together with marked frontal midline theta activity. Compared to a resting state, the dynamics of the electrical activity in the brain showed an increase in the global field power integral and a decrease in generalized frequency and spatial complexity.

Adult↗

PubMed2002

Alterations of quantitative EEG and mini-mental state examination in interferon-alpha-treated hepatitis C.

We have recently observed a diffuse slowing of brain waves using serial quantitative electroencephalographic (qEEG) examinations in interferon (IFN)-alpha-treated chronic hepatitis C patients. However, it remains unclear how this alteration could be assessed. We evaluated the correlation between the qEEG changes and three tests of mental status, including the Mini-Mental State Examination (MMSE), in such patients. This is the first study to undertake a clinical evaluation of the adverse effects on brain function due to IFN. We undertook blind, prospective and serial qEEG examinations on 56 chronic hepatitis C patients at three independent hospitals. IFN-alpha was administered intramuscularly at a dose of 9 x 10(6) IU daily for the first 4 weeks and then 3 times/week for the next 20 weeks. Serial EEGs were obtained before, at 2 and 4 weeks of treatment, and after the IFN-alpha treatment. The absolute power values of each frequency band in each patient at different stages of treatment were recorded by qEEG. Each patient was assessed by the MMSE, Hamilton Rating Scale for Depression (HSD), and Hamilton Rating Scale for Anxiety (HSA). We statistically evaluated the correlations between the changes in power values and alterations of scores on the mental status tests during IFN-alpha treatment. The decreased scores observed on the MMSE ranged from 2 to 5 points at both 2 and 4 weeks of IFN-alpha treatment. There were no significant differences in age distribution for each decreased score on the MMSE. As the alteration in MMSE score during IFN treatment increased, the alteration in absolute power values for the slow waves during IFN treatment increased significantly, while that for the alpha 2 and fast waves during treatment decreased significantly. However, the changes in the HDS and HSA revealed no significant correlations. The alteration of the qEEG was reversible after the treatment. MMSE scores represent one screening method for the clinical assessment of IFN-alpha-induced alterations of brain function.

Adult↗

PubMed1991

Reversible quantitative EEG changes in a case of cyclic vomiting: evidence for migraine equivalent.

Medical experts have disputed whether childhood cyclic vomiting is a manifestation of epilepsy or a migraine equivalent. Quantitative EEG provides an objective measure of changes in brain activity during and between episodes. This paper reports reversible changes involving two episodes in a patient whose history included cyclic vomiting and emotional/behavioural problems. Abnormal delta activity seen during both episodes resolved at follow-up, when the patient asymptomatic. The brain wave changes counter the hypothesis that vomiting in these patients is psychosomatic, and support the interpretation of cyclic vomiting as a migraine equivalent.

Adolescent↗

PubMedDate not supplied

[Study of mapped slow auditory evoked potentials in Alzheimer's disease].

BACKGROUND: Alzheimer's disease affects around 500,000 persons in Italy and its diagnosis remains essentially clinical. Our aim was to contribute to the diagnosis of Alzheimer's disease by mapping auditory evoked potentials (AEP). Evoked potentials represent the electric response of the CNS to an external stimulus and can be represented as a sequence of waves. Brain mapping allows a chromotopogram to be compiled showing chromatic maps. METHODS: A group of 12 patients were studied aged between 68 and 84 years old who were referred to our attention at the Department of Geriatrics and Gerontology at Catania University and the A.O. Cannizzaro, Geriatrics Unit. All patients completed an assessment form (MM-SE, ADAS) and underwent brain NMR and AEP. RESULTS: These tests enabled us to identify two types of patients (Group A and Group B) based on the responses shown. The overall evaluation of results revealed that patients with Alzheimer-type dementia present an anomalous cortical neurogenic response to mapped AEP, and that patients in Group A showed anomalous wave morphology, latency and localisation and asymmetric impregnation. The data gathered in this study did not confirm any specific characteristics of AEP given that similar anomalies are found in metabolic dysfunction syndromes and demyelination pathologies. CONCLUSIONS: However, while it does not constitute a specific technique for screening against Alzheimer's disease, the mapping of AEP may contribute to the diagnosis of this disease.

Aged↗

PubMed1992

Response of canine brain loci to intracerebroventricular thyroxine.

The effect of intracerebroventricular T4 on certain hypothalamic i.e., POA and VMN and cortical i.e., HPC and CO loci was investigated by recording their electroencepgraphic activity after chronic implantation of cannulae and bipolar electrodes in ten male dogs. Recordings were made for two hours after the microinjection. The predominant pattern of EEG activity was a synchrony of brain waves in all derivations except for POA where biphasic desynchronization-synchronization was observed. Final synchrony suggest refractoriness of these loci to T4 which might be playing a protective role.

Animals↗

PubMed1979

Possible microwave mechanisms of the mammalian nervous system.

The hypothesis is examined that the living mammal generates and uses electromagnetic waves in the lower microwave frequency region as an integral part of the functioning of central and peripheral nervous systems. Analysis of the potential energy of a protein integral to the neural membrane compared to that of an extracellular positive ion yields major known features of action potential generation, and identification of the integral protein as a microwave emitter and absorber by changes in rotational energy state. Prolate spheroidal analysis of the adult human brain/skull cavity shows capability to support modes in the range 200 MHz to 3 GHz; spatial mode properties correspond to gross anatomy and neuromorphology of the brain. Phase-lock loop interaction between lower microwave modes and action potential conduction results in pulse microwave/action potential generation observable by EEG instrumentation as brain waves; alpha waves occur if the corpus callosum is the major neural tract involved. Spatially consistent Lorentz forces of standing microwaves provide physical basis for correspondence of spatial properties of microwave modes with brain anatomy, and for the formation of myelin sheath and the nodes of Ranvier on larger neurons.

Action Potentials↗

PubMed2002

Hydrogen sulfide exposure without loss of consciousness: chronic effects in four cases.

Adverse effects of acute exposure to hydrogen sulfide (H2S) are well documented, but long-term effects of occupational exposure to low levels of the gas are not. To evaluate effects of such exposure we performed physical, neurologic, psychiatric, and chemosensory (smell and taste) examinations of four workers who were present but did not lose consciousness when the gas was accidentally released at a construction site. None of the four workers tested positive for functional problems, but all met diagnostic criteria for at least three, and up to eight, H2S-induced neuropsychiatric clinical disorders and from zero to two subclinical disorders. All four had abnormal P300 evoked responses (electrical neurophysiologic tests of brain waves). Our data indicate that exposures to even relatively low concentrations of H2S are hazardous. A rigorous epidemiologic investigation of persons who work with H2S is warranted.

Accidents, Occupational↗

PubMed2005

Evolutionary approaches to understanding sleep.

A major controversy over REM sleep's role in memory processing may owe to inadequate allowances for the highly conservative nature of evolutionary adaptations. The controversy hinges on whether NREM sleep, alone, retains primitive memory processing capabilities. The selective pressure for primitive sleep, is thought to have been the need to obviate conflicts between enormous neural processing requirements of complex visual analysis and split-second control of movements, on the one hand, and memory processing, on the other. The most efficient memory processing during mammalian and avian sleep appears to be a two-step process: synapses in individual component circuits of events are reinforced primarily by slow brain waves during NREM sleep, with the reinforced components temporally bound by fast waves, and manifested as dreams, during REM sleep. This dual action could account for partitioning of sleep periods into multiple NREM-REM cycles. It is proposed that in the absence of REM sleep, all needed memory processing can be accomplished by NREM sleep, alone, though less efficiently. Many symptoms of fatal familial insomnia are attributed to subnormal nightly reinforcement of brain circuitry because of almost total loss of sleep, and compensatory responses thereto during waking. During this disorder, sensory circuitry seemingly is spared by virtue of its supernormal reinforcement during almost continuous waking. Contrariwise, sparing of an adult's 'higher faculties' in encephalitis lethargica appears to owe to supernormal circuit reinforcement during almost continuous sleep.

Awareness↗

PubMed1977

Genetic control of ethanol action on the central nervous system. An EEG study in twins.

The purpose of the investigation is to claify the genetic contribution to the interindividual variability of ethanol action on the central nervous system. The 52 adult male healthy twin pairs (26 MZ, 26 DZ) got 1.2 ml/kg ethanol p.o. under standardized conditions; furthermore, 13 non-twin subjects were repeatedly subjected to the same procedure in order to test the intraindividual variability. The EEG was recorded before and 60, 120, 180, and 240 min after alcohol intake. The EEGs were off-line analyzed by means of a computer program for time domain analysis. As was already known, on the average alcohol led to a better synchronisation of the EEG, i.e., the number of beta-waves decreased whereas the number of alpha- and theta-waves increased. The extent of the alcohol effect on the EEG varied enormously between individuals; however, the EEGs of MZ twins proved to react indentically to alcohol loading, whereas the EEGs of DZ twins became mor dissimilar during the course of the experiment. The low-voltage EEG presumably is resistant to alchohol; furthermore, it is supposed that there exists a special beta-prone EEG-type which is also genetic in origin. The identical EEG reaction of MZ twins to alcohol loading could not be attributed to more similar blood alcohol concentrations. It is hypothesized that the differences in the extent of the alcohol effect on the EEG between individuals might reflect differences in the sensitivity of the ascending reticular activating system. In the literature it has frequently been reported that alcoholics have preferentially brain wave patterns which are poorly synchronized. These findings are discussed in the light of the present results.

Adult↗

PubMed2001

Electricity as a medium of psychic life: electrotechnological adventures into psychodiagnosis in Weimar Germany.

When electricity became a commodity in 1900, it furnished Germany with new attractions and revolutionized everyday life with all kinds of tools and gadgets; it also opened up a new space for investigating psycho-physical interaction, reviving ideas of a close linkage between psychic life and electricity. The paper traces the emergence of this electro-psychological framework beyond "electroencephalography," the recording of electrical brain waves, to "diagnoscopy," personality profiling by electric phrenology. Diagnoscopy opens a window onto the scientific and public cultures of electricity and psychical processes in Weimar Germany. It garnered enormous attention in the press and was quickly taken up by several institutions for vocational guidance, because it offered a rapid and technological alternative to laborious psychological testing or "subjective" interviewing. Academic psychology and leading figures in brain research reacted with horror; forging counter measures which finally resulted in this technique being denounced as quackery. A few years later, the press celebrated electroencephalography as a mind-reading device, whereas the neuroscientists remained initially skeptical of its significance and the very possibility of an "electroencephalogram" (EEG) before they adapted electroencephalography as a tool for representing various neuro-psychiatric conditions in patterns of recorded signals. The blending of psychophysiology and electrical engineering marks the formation of an electric epistemology in scientific as well as public understanding of the psyche. The transformations of electrodiagnosis from diagnoscopy to the EEG are indicative of a cultural shift in which electricity changed its role from being the power source for experimental apparatuses to becoming a medium of psychic processes.

Electricity↗

PubMed1990

[Effect of thyrotropin-releasing hormone (TRH) on EEG topography].

EEG topography by a microcomputer system (ATAC-3700 Nihon-Kohden) was performed in the rabbit in order to investigate the mechanism of TRH action on the brain wave. Power spectral analysis was carried out using a fast Fourier transform algorithm. The square root of the power spectra was defined as the equivalent potential over each frequency band by Ueno & Matsuoka's method. Potential fields of EEG frequency band were printed out on the topographic maps. The potentials of the electrocortical delta and theta waves were high, while the potentials of the alpha, beta 1 and beta 2 waves were low. Stimulation of the nucleus ventralis anterior (VA) by 3 Hz and 8 Hz resulted in a decrease in these potentials, especially, those of the alpha, beta 1 and beta 2 waves. The potentials of the alpha and fast waves were increased following unilateral destruction of VA. In the rabbit, in which TRH 0.5 mg/kg had been administered beforehand, there was no decrease in the potential of each wave induced by stimulation of VA with frequencies of 3 Hz and 8 Hz. The findings suggest involvement of the diffuse thalamocortical projection system in the activation of EEG by TRH.

Animals↗

PubMedDate not supplied

[Validity of "lump approximation" for the description of overall brain electrical activity using an simulation model].

Brain rhythmic activity model on the basis of space uniform neuronal network consisting of excitatory and inhibitory elements was examined. Network activity description by "lump approximation" was compared with simulation model computation. Lump approximation parameters dependence on the properties of neurons and synapses as well as conditions of the transition between network activity types which imitate desynchronous (low voltage fast activity) and synchronous (high voltage slow waves) brain activities were obtained.

Animals↗

PubMed1964

SLEEP PATTERN OF TOOTH-GRINDING: ITS RELATIONSHIP TO DREAMING.

Simultaneous recordings of brain waves, eye movements, and masticatory muscle potentials throughout the night demonstrate a temporal relationship between episodes of bruxism (nocturnal grinding of the teeth) and periods of rapid eye movements indicative of dreaming.

Biomedical Research↗