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[Advance of technology in the analysis of brain wave in patients with schizophrenia].
Recent advance of several leading technologies including EEG, EP and BEAM applied in the analysis of brain wave in schizophrenic patients was discussed in this paper. The perspectives for the application of these technologies and some opinions from the authors are also presented.
Alpha brain wave production as an interpolated task in a Brown-Peterson paradigm.
Rehearsal, backward counting, and production of alpha brain-waves were used as interpolated tasks in a Brown-Peterson paradigm to determine their effect upon verbal retention. A within-subjects design was used in which trained subjects were told on a given trial either to produce alpha rhythm, mentally rehearse, or count backward following presentation of a CCC trigram. Results for the backward-counting condition duplicate, for the retention intervals used, the shape of the classic Peterson and Peterson forgetting curve but indicate little loss of memory in either the rehearsal or alpha conditions. No siginificant difference was found between the alpha production and rehearsal conditions.
The effect of the Relaxodont brain wave synchronizer on endodontic anxiety: evaluation by galvanic skin resistance, pulse rate, physical reactions, and questionnaire responses.
The effects of a brain wave synchronizer (BWS) on endodontic (root canal) anxiety was evaluated in the clinical practices of the senior author. The experimental groups were: (1) a verbal method (routine calming words by dentist) plus BWS (N = 10) and (2) verbal method plus BWS and alpha relaxation tape (N = 10). The control group was verbal method alone (N = 10). All three groups were evaluated during a complete endodontic treatment by the use of galvanic skin resistance (GSR), pulse rate (PR), physical responses, and pre- and post-treatment questionnaires. Recordings were made during the following periods: (1) start; (2) local anesthetic injection; (3) rubber dam application; (4) drilling; (5) x-ray taking; (6) instrumentation; (7) obturation; and (8) conclusion. Results showed that the experimental groups were significantly better than the control group in the reduction of endodontic anxiety. The findings reinforced the belief that local anesthetic injection is the most anxiety producing aspect of endodontic treatment.
Familial brain wave patterns: study of a 12-sib family.
In the sense of a paradigm for the heritability of complex psychiatric disorders, we compared the brain wave patterns of a 12-sib family with those of 144 unrelated controls and with those of 14 pairs of monozygotic twins. Under constant experimental conditions, electroencephalogram (EEG) parameters generally displayed a broad range of inter-individual differences, but were also remarkably stable over time within each subject, thus suggesting that the variation of EEG parameters forms a continuous phenotypic range rather than discrete phenotype classes. The distributions of all EEG parameters were found to be unimodal but significantly different from a normal distribution. Although an unimodal distribution speaks in favor of a polygenic additive mode of inheritance, this may not necessarily be true. Our findings might reflect the fact that a symmetric environmental distribution is converted through the underlying genotypes' norm of reaction into an asymmetric phenotype distribution. On the other hand, the distributions of the power-related EEG parameters were not that clearly unimodal, and with a larger sample size a trimodal solution might have become significant. With respect to the between-sib EEG similarity, we found the empirically derived value to be approximately half that of the within-subject similarity at 14-day intervals and of the within-pair similarity of monozygotic twins. This finding confirmed earlier results on monozygotic twins brought up together and reared apart, concerning the estimated value of h2. All in all, the EEG paradigm has clearly demonstrated that the methods of quantitative genetics represent a powerful tool once phenotypes designed to assess the variation of a trait are based on dimensional quantities.
Nongenetic pathologic developments of brain-wave patterns in monozygotic twins discordant and concordant for schizophrenia.
Evidence from previous studies has suggested that the inter-individual differences in human brain-wave patterns (EEG) are predominantly determined by genetic factors. In particular, the within-pair EEG concordance of monozygotic (mz) twins was found to be typically as high as r = 0.81 across channels and frequency bands, thus being comparable to that between repeated assessments on the same individual with typically r = 0.83. Yet our investigations into mz twins discordant and concordant for schizophrenia yielded a significantly reduced within-pair EEG concordance for both, the pairs discordant for schizophrenia and the pairs concordant for schizophrenia (with concordance for schizophrenia assessed through a syndrome-oriented approach). A multivariate discriminant function of EEG parameters distinguished in a reproducible way between affected and unaffected subjects at an overall performance of >75% correctly classified subjects, while the severity of illness, as derived from EEG-differences between affected and unaffected subjects, was closely related to the severity of illness as provided by psychopathology syndrome scores. Consequently, EEG anomalies associated with schizophrenia and manifested differently in the mz co-twins concordant for schizophrenia are likely the effect of nongenetic, pathologic processes that evolved independently in the co-twins' genetically identical brains once the illness began to progress. The existence of such nongenetic processes would suggest a modification of the standard phenotype-to-genotype search strategies of molecular-genetic studies that aim to link the schizophrenia phenotype to genetic vulnerability factors.
Neural mechanisms underlying brain waves: from neural membranes to networks.
In this review, a number of experimental findings and theoretical concepts that have led to new insights into the mechanisms underlying brain waves are presented. At the cellular level, the new evidence that certain types of neuron have intrinsic oscillatory properties that may underlie rhythmic EEG activities is discussed. In particular, the question of whether spindle oscillations are autonomous or input-dependent is addressed. At the neural network level, the main circuits of the thalamus and cortex that are responsible for the occurrence and modulation of spindles and alpha activity are described. In addition, the properties of rhythmic activities outside the alpha band are considered, particularly in relation to the prominent beta activity of the visual cortex. At the theoretical level, the possibility that neural networks may behave as complex dynamic systems with the properties of deterministic chaos is discussed. Finally, the fact that brain rhythms may have functional implications for the working of neural networks is examined in relation to 2 cases: the possibility that oscillations may subserve a gating function, and that oscillations may play a role in the formation of assemblies of neurons that represent given stimulus patterns.
Studies on mescaline. III. Action in epileptics; clinical observations and effects on brain wave patterns.
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The influence of oxygen lack on brain waves in man.
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[Clinical features of hypothyroidism; studies on intelligence acquired after prolonged thyroidine therapy and on the picture of brain waves].
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Influence of x-ray radiation on human brain wave.
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[Fatigue of the accommodative system and brain waves].
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Limit cycle model for brain waves.
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Riding the biological brain wave.
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Decoupling neural networks from reality: dissociative experiences in torture victims are reflected in abnormal brain waves in left frontal cortex.
From a neuroscience perspective, little is known about the long-term effect of torture. Dissociative experiences and posttraumatic stress disorder are often the results of this experience. We examined psychological dissociation within a group of 23 torture victims and report its manifestations within neural networks in the human brain. In particular, we observed that dissociative experiences are associated with slow abnormal brain waves generated in left ventrolateral frontal cortex. Given that focal slow waves often result from depriving neural networks of major input, the present results may indicate decoupling of frontal affective processors from left cortical language areas. This interpretation is consistent with the fact that disturbed access to structured verbal memory concerning traumatic events is a core feature of the dissociative experience.
Stationarity and normality of distribution of rat cortical brain waves.
Establishing the stationarity and statistical distribution of potentials recorded from the nervous system is crucial for the application of frequency analysis. Both parameters were determined in the electrocorticograms of six adult Wistar rats during wakefulness and desynchronized sleep, during both of which desynchronization prevails. Stationarity of the signals was found to occur during at least 20 s in both states of the wakefulness-sleep cycle. A normal distribution was also found for at least 6.7 s. These findings provide strong support for the use of frequency analysis of brain waves as a reliable method to quantify neural electro-oscillograms.