[Intermittent noise and the brain waves, especially alpha-wave].
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Adult↗
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Results for “Brain waves”
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The role of brain waves in learning and other integrative functions.
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Brain↗
Brain waves following remembered faces index conscious recollection.
At a glance, one can often determine whether a face belongs to a known individual. To investigate brain mechanisms underlying this memory feat, we recorded EEG signals time-locked to face presentations. In the study phase, 40 unknown faces were presented, 20 of which were accompanied by a voice simulating that person speaking. Instructions were to remember the faces with spoken biographical information (R-faces) and to forget the others (F-faces). In the test phase, famous and non-famous faces were presented in a visually degraded manner. Subjects made two-choice fame judgments and priming was observed in the form of faster and more accurate responses for old than for new non-famous faces. Priming did not differ between R-faces and F-faces. In a second experiment, faces were not degraded at test and behavioral responses were made only when faces were presented twice in immediate succession. Brain potentials elicited 300 to 900 ms after stimulus onset from frontal and parieto-occipital scalp regions were larger for R-faces than for F-faces. Recognition tested later was more accurate for R-faces than for F-faces. Because the study-phase manipulation influenced recognition but not priming, we conclude that this procedure succeeded in isolating neural correlates of recollective processing from more automatic uses of face memory as indexed by priming.
Acoustic Stimulation↗
Evidence for slow brain waves: a dynamical approach.
Various techniques of non-linear dynamics have been applied with success to EEG data and have provided a new insight into brain dynamics. Among these the 'recurrence plot' is a powerful tool for revealing the presence of drift or periodicities and is easily obtained in the framework of a non-linear dynamical analysis. When this analysis is applied to the EEG recorded from a patient suffering from Creutzfeldt-Jakob disease one observes the presence of slow periodicities of the order of 58 sec. We suggest that the recurrence plots are powerful tools for discovering hidden periodicities of EEG as well as the degree of stationarity of brain activity.
Brain↗
Effects of consciousness on human brain waves following binocular rivalry.
When the two eyes of an observer are exposed to conflicting stimuli, they enter into binocular rivalry and the two possible percepts will alternate in dominance. We investigated neural activity and its time course following binocular rivalry by measuring human event-related brain potentials to transitions from rivalrous to non-rivalrous stimulation. When these changes did not entail a change in conscious perception they elicited a markedly attenuated N1 component and a delayed and attenuated P3 peak as compared to percept-incompatible changes and non-rivalrous control conditions. These results suggest that in humans binocular rivalry is resolved at latest in extrastriate visual areas.
Adult↗
[On the diagnostic value of the brain wave pattern in hepato-portal encephalopathy: together with a clinical-statistical contribution to the question of neurologic and psychic changes in liver cirrhosis and portacaval anastomosis operations].
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Brain Diseases↗
Brain wave components of the contingent negative variation in humans.
In a contingent negative variation paradigm with two stimuli paired at an interstimulus interval of 4 seconds, two distinct waveforms having functional and topographic differences are observed. An early wave is maximal over the frontal cortex and is elicited by the warning stimulus. A later wave, maximal over the motor cortex, precedes the imperative stimulus and is identified with preparation for motor response.
Brain↗
Cardiac deceleration and E-wave brain potential components in young, middle-aged and elderly adults.
Event-related potentials (ERPs), heart rate, and behavioral data were recorded from young, middle-aged, and elderly adults during an S1-S2 recognition memory paradigm. Anticipatory and evoked cardiac decelerations decreased significantly with age, as did the accuracy of recognition memory. The E-wave prior to S2 did not differ with age, however, and was not correlated with heart rate deceleration in any age group. Correlations between physiological measures and performance were weak in all groups. Taken together, the data provide little support for the hypothesis that the poorer recognition memory of older adults is related to an increasing uncoupling of E-wave and anticipatory heart rate with age.
Adult↗
Analysis of brain wave records from Gemini flight GT-7 by computations to be used in a thirty day primate flight.
It is planned to study central nervous, cardiovascular and metabolic functions in a 6.8 kg macaque monkey (Macaca nemestrina) flown in earth orbit for a period of 30 days during 1967. Monitoring of central nervous functions will be by electroencephalographic (EEG) electrodes in surface and deep brain structures, and by electromyographic (EMG) recordings from neck and trunk musculature. Eye movements will be recorded by the electro-oculogram (EOG) and galvanic skin responses (GSR) will be assessed from the skin of the foot. Respiration will be recorded with an impedance pneumogram (ZPG), together with the electro-cardiogram (EKG). Behavioral tasks will involve tests of perception and recent memory (delayed matching to sample) and eye-hand coordination tests of vestibular functions and spatial orientation. Urine will be collected by a special catheterization technique and subjected to in-flight recording. Our extensive development of EEG spectral analysis techniques has proven the feasibility of accurate assessment of states of alertness, particularly in relation to decision-making requirements, and states of drowsiness, fatigue and detection of levels of sleep, including dream states. We have applied these techniques to approximately 60 hr of EEG data gathered on one subject in a Gemini astronaut flight (GT-7). Data will be presented on states of sleep and wakefulness in this subject during the first 55 hr of flight, with reference to possible changes induced by the space environment.
Animals↗
Applicability of brain wave biofeedback to substance use disorder in adolescents.
Neurofeedback treatment for addictions in adults is probably efficacious, and several reported approaches are described with their indications. Neurofeedback is promising as a treatment modality for adolescents, especially those with stimulant abuse and attention and conduct problems. It is attractive as a medication-free, neurophysiologic, and self-actualizing treatment for a substance-based, brain-impaired and self-defeating disorder. More research, beginning with case reporting, is needed to assess use and efficacy in adolescents.
Adolescent↗
Different event-related patterns of gamma-band power in brain waves of fast- and slow-reacting subjects.
Fast- and slow-reacting subjects exhibit different patterns of gamma-band electroencephalogram (EEG) activity when responding as quickly as possible to auditory stimuli. This result appears to confirm long-standing speculations of Wundt that fast- and slow-reacting subjects produce speeded reactions in different ways and demonstrates that analysis of event-related changes in the amplitude of EEG activity recorded from the human scalp can reveal information about event-related brain processes unavailable using event-related potential measures. Time-varying spectral power in a selected (35- to 43-Hz) gamma frequency band was averaged across trials in two experimental conditions: passive listening and speeded reacting to binaural clicks, forming 40-Hz event-related spectral responses. Factor analysis of between-subject event-related spectral response differences split subjects into two near-equal groups composed of faster- and slower-reacting subjects. In faster-reacting subjects, 40-Hz power peaked near 200 ms and 400 ms poststimulus in the react condition, whereas in slower-reacting subjects, 40-Hz power just before stimulus delivery was larger in the react condition. These group differences were preserved in separate averages of relatively long and short reaction-time epochs for each group. gamma-band (20-60 Hz)-filtered event-related potential response averages did not differ between the two groups or conditions. Because of this and because gamma-band power in the auditory event-related potential is small compared with the EEG, the observed event-related spectral response features must represent gamma-band EEG activity reliably induced by, but not phase-locked to, experimental stimuli or events.
Acoustic Stimulation↗
The musical brain: brain waves reveal the neurophysiological basis of musicality in human subjects.
To reveal neurophysiological prerequisites of musicality, auditory event-related potentials (ERPs) were recorded from musical and non-musical subjects, musicality being here defined as the ability to temporally structure auditory information. Instructed to read a book and to ignore sounds, subjects were presented with a repetitive sound pattern with occasional changes in its temporal structure. The mismatch negativity (MMN) component of ERPs, indexing the cortical preattentive detection of change in these stimulus patterns, was larger in amplitude in musical than non-musical subjects. This amplitude enhancement, indicating more accurate sensory memory function in musical subjects, suggests that even the cognitive component of musicality, traditionally regarded as depending on attention-related brain processes, in fact, is based on neural mechanisms present already at the preattentive level.
Adolescent↗
Human brain wave activity during exposure to radiofrequency field emissions from mobile phones.
The aim of this study was to determine whether there is an effect of mobile phone electromagnetic field emissions on the human electroencephalograph (EEG). EEG recordings from ten awake subjects were taken during exposure to radiofrequency (RF) emissions from a mobile phone positioned behind the head. Two experimental trials were conducted. In the first trial, RF exposures were generated by a GSM mobile phone with the speaker disabled and configured to transmit at full-radiated power. During the second trial, exposures were generated by a non-modified GSM mobile phone in active standby mode. For each trial, subjects were exposed in five minute intervals to a randomized, interrupted sequence of five active and five sham exposures. The experiment was conducted under single-blind conditions. The average EEG band power in active exposure recordings was compared to corresponding sham recordings. Statistical tests indicated significant difference in the full-power mode trial within the EEG alpha (8-13 Hz) and beta (13-32 Hz) bands. A subsequent statistical analysis of median spectral power in discrete EEG rhythms revealed significant differences in 7 of the 32 distinct frequencies overall. In conclusion, the results of this study lend support to EEG effects from mobile phones activated in talk-mode.
Adolescent↗
Temporal fluctuations in coherence of brain waves.
As a measure of dynamical structure, short-term fluctuations of coherence between 0.3 and 100 Hz in the electroencephalogram (EEG) of humans were studied from recordings made by chronic subdural macroelectrodes 5-10 mm apart, on temporal, frontal, and parietal lobes, and from intracranial probes deep in the temporal lobe, including the hippocampus, during sleep, alert, and seizure states. The time series of coherence between adjacent sites calculated every second or less often varies widely in stability over time; sometimes it is stable for half a minute or more. Within 2-min samples, coherence commonly fluctuates by a factor up to 2-3, in all bands, within the time scale of seconds to tens of seconds. The power spectrum of the time series of these fluctuations is broad, extending to 0.02 Hz or slower, and is weighted toward the slower frequencies; little power is faster than 0.5 Hz. Some records show conspicuous swings with a preferred duration of 5-15s, either irregularly or quasirhythmically with a broad peak around 0.1 Hz. Periodicity is not statistically significant in most records. In our sampling, we have not found a consistent difference between lobes of the brain, subdural and depth electrodes, or sleeping and waking states. Seizures generally raise the mean coherence in all frequencies and may reduce the fluctuations by a ceiling effect. The coherence time series of different bands is positively correlated (0.45 overall); significant nonindependence extends for at least two octaves. Coherence fluctuations are quite local; the time series of adjacent electrodes is correlated with that of the nearest neighbor pairs (10 mm) to a coefficient averaging approximately 0.4, falling to approximately 0.2 for neighbors-but-one (20 mm) and to < 0.1 for neighbors-but-two (30 mm). The evidence indicates fine structure in time and space, a dynamic and local determination of this measure of cooperativity. Widely separated frequencies tending to fluctuate together exclude independent oscillators as the general or usual basis of the EEG, although a few rhythms are well known under special conditions. Broad-band events may be the more usual generators. Loci only a few millimeters apart can fluctuate widely in seconds, either in parallel or independently. Scalp EEG coherence cannot be predicted from subdural or deep recordings, or vice versa, and intracortical microelectrodes show still greater coherence fluctuation in space and time. Widely used computations of chaos and dimensionality made upon data from scalp or even subdural or depth electrodes, even when reproducible in successive samples, cannot be considered representative of the brain or the given structure or brain state but only of the scale or view (receptive field) of the electrodes used. Relevant to the evolution of more complex brains, which is an outstanding fact of animal evolution, we believe that measures of cooperativity are likely to be among the dynamic features by which major evolutionary grades of brains differ.
Brain↗
Entropy concept in relation to brain waves and evoked potentials: critique of a physical approach.
Basar's view that the larger the number of synchronized and coupled participating neural generators, i.e., the lower the entropy of the neural systems, the lower the responsiveness of the system, and vice versa, was reconsidered experimentally and theoretically, in the light of current knowledge about the relationship between EEG states and evoked potentials. It was found that the morphology as well as the magnitude of the somatosensory evoked potentials was the same during synchronized (low entropy) and desynchronized (high entropy) EEG states in normal human subjects. Baclofen caused an increase in the somatosensory evoked potentials without affecting the EEG in unanaesthetized dogs. In the less complicated and more limited systems such as the skeletal muscle and monosynaptic reflex paradigms, an inverse relationship was established between the entropy state and responsiveness. This relationship can be simply explained by the neurophysiological facts such as Na-inactivation process at the excitable membranes and the refractory states of the neural generators. These results are consistent with those from the literature; the evoked potentials are usually large when recorded during synchronized EEG states and vice versa. It is suggested that, at least, the well established neurophysiological facts should not be ignored in physical approaches to neural mechanisms, especially when it concerns highly complex systems such as the brain.
Animals↗
Case study: neurological brain waves causing serious behavioral brainstorms.
A case highlighting the association of epilepsy with psychopathology is reported. The patient suffered a rare and extreme behavioral disturbance, characterized by persistent disruptive behavior and intermittent bizarre and violent outbursts. These outbursts often appeared purposeful, but some of them were later diagnosed as ictal manifestations of temporal lobe epilepsy. Temporal lobectomy resulted in remission both of the epilepsy and of the more persistent behavioral disturbance. lctal behavioral change was masked by interictal behavioral disturbance, leading to delayed diagnosis and prolonged psychosocial dysfunction. It is important to record the paroxysmal abnormal behavior with simultaneous electroencephalographic recording if there is a suspicion of organic disease. Physical and psychosocial factors in the relationship between epilepsy and extreme psychiatric disturbance are considered. This case demonstrates how successful epilepsy treatment may produce amelioration of associated psychiatric disturbance.
Attention Deficit and Disruptive Behavior Disorder↗
Functional properties of sub-bands of oscillatory brain waves to pattern visual stimulation in man.
The scalp recorded transient visual evoked potential (VEP) represents the massed activity of a large number of neurons of the human visual cortex. Animal studies show that intracerebrally-recorded high frequency electrical activity represents binding between neurons participating in a cooperative response. We evaluated the relationship between scalp recorded high frequency activity and transient VEPs elicited by a repetitive (grating) pattern. Stimuli were 1 and 4 cycles/degree sinusoidal gratings, presented in an on/off mode. Following conventional averaging, the discrete wavelet transform (DWT) was applied. Multi-resolution decomposition was used to divide the responses into 6 orthogonal frequency bands. The results show that high frequency oscillatory activity in the beta and gamma frequency range is closely related in time to the N70 peak of the simultaneous VEP. Power in both bands is modulated by spatial frequency. Beta range response to hemifield stimulation recorded over a chain of electrodes over the occipital area lateralizes in the same manner as N70, while gamma range activity is insensitive to lateralization and is more closely linked to foveal stimulation. This dissociation between beta and gamma range activity suggests that different bands of high frequency oscillatory activity in humans, linked to visual stimulation, may represent different aspects of visual processing.
Adolescent↗
Changes in sleep quality and brain wave patterns following initiation of an efavirenz-containing triple antiretroviral regimen.
BACKGROUND: Initiation of efavirenz is commonly associated with sleep disturbances. Assessment of sleep using the electroencephalogram and electromyogram enables sleep staging to be performed and changes following the introduction of therapy to be evaluated. METHODOLOGY: Using standardized sleep-staging methodology, we investigated sleep staging and sleep quality by patient self-report in an open-label cohort pilot study. Assessments were performed prior to the initiation of efavirenz, 2 weeks after the initiation of efavirenz and 3 months after the initiation of efavirenz. The study included HIV-positive individuals without central neurological disease who were naive to antiretroviral treatment. All patients initiated treatment with two nucleoside reverse transcriptase inhibitors in combination with efavirenz. RESULTS: Ten patients completed all three study visits. Patients reported an increase in recollection of dreams and morning sluggishness after the initiation of efavirenz which persisted for 3 months. Sleep-staging data indicated a modest reduction in stage 2 sleep with a corresponding increase in deep sleep stage 4 and a modest increase in rapid eye movement (REM) sleep. Overall sleep maintenance efficiency did not significantly change from baseline. Changes in sleep staging were most marked 2 weeks after the initiation of efavirenz but remained different from baseline patterns at 3 months. CONCLUSION: The data indicate that efavirenz has a modest but persistent impact on the time spent in several key sleep stages. Patients reported persistence of dream recollection but remained satisfied with sleep quality and overall quality of life.
Alkynes↗