Localization of a gene for the human low-voltage EEG on 20q and genetic heterogeneity.

The localization of a gene responsible for a normal variant of the human electroencephalogram to the distal part of chromosome 20q is reported. A linkage analysis, including 17 families with 191 individuals, tested with 73 RFLPs and 22 blood and serological markers, was performed for the low-voltage electroencephalogram. This is a normal variant of the human electroencephalogram with an autosomal dominant mode of inheritance. The results present strong evidence for close linkage with the highly polymorphic marker CMM6 (D20S19) and for genetic heterogeneity.     

Influence of artificial air ionisation on the human electroencephalogram

Exposure of 20 subjects to negative ionisation was monitored by EEG. Negative ionisation was supplied by an Ionotron apparatus (Amcor-Amron, Herzlia-Israel) with an output of 3.5 × 10⁵ ions/(cm³ · sec) at 1 m distance. Objective findings in ten normal subjects showed reduction of the frequency of the alpha-waves from 10 or 11 down to 9 or 8 Hz, increase of the amplitude by up to 20%, advance of the alpha rhythm pattern from the occipital to the frontal area and general synchronisation of the EEG records of both hemispheres. These reactions were suppressed in 10 subjects by tranquillisers. Subjective findings included relaxation, alertness, improved working capacity and relief from the Serotonin Irritation Syndrome produced by the positive ionisation of hot, dry desert winds.This paper is devoted to the memory of Dr Igho H.Kornblueh, the pioneer of ion therapy, who passed away in 1973 in Philadelphia. Working on this project in 1957 he concluded "that further research on the effects of ionisation on the EEG is warranted".This report was prepared with the technical assistance of Mrs Suzi Alpern and B.Shalita.     

Development of the nocturnal sleep electroencephalogram in human infants

The development of nocturnal sleep and the sleep electroencephalogram (EEG) was investigated in a longitudinal study during infancy. All-night polysomnographic recordings were obtained at home at 2 wk and at 2, 4, 6, and 9 mo after birth (analysis of 7 infants). Total sleep time and the percentage of quiet sleep or non-rapid eye movement sleep (QS/NREMS) increased with age, whereas the percentage of active sleep or rapid eye movement sleep (AS/REMS) decreased. Spectral power of the sleep EEG was higher in QS/NREMS than in AS/REMS over a large part of the 0.75- to 25-Hz frequency range. In both QS/NREMS and AS/REMS, EEG power increased with age in the frequency range <10 Hz and >17 Hz. The largest rise occurred between 2 and 6 mo. A salient feature of the QS/NREMS spectrum was the emergence of a peak in the sigma band (12-14 Hz) at 2 mo that corresponded to the appearance of sleep spindles. Between 2 and 9 mo, low-frequency delta activity (0.75-1.75 Hz) showed an alternating pattern with a high level occurring in every other QS/NREMS episode. At 6 mo, sigma activity showed a similar pattern. In contrast, theta activity (6.5-9 Hz) exhibited a monotonic decline over consecutive QS/NREMS episodes, a trend that at 9 mo could be closely approximated by an exponential function. The results suggest that 1) EEG markers of sleep homeostasis appear in the first postnatal months, and 2) sleep homeostasis goes through a period of maturation. Theta activity and not delta activity seems to reflect the dissipation of sleep propensity during infancy.     

Molecular genetic study of human arginase deficiency

We have explored the molecular pathology in 28 individuals homozygous or heterozygous for liver arginase deficiency (hyperargininemia) by a combination of Southern analysis, western blotting, DNA sequencing, and PCR. This cohort represents the majority of arginase-deficient individuals worldwide. Only 2 of 15 homozygous patients on whom red blood cells were available had antigenically cross-reacting material as ascertained by western blot analysis using anti-liver arginase antibody. Southern blots of patient genomic DNAs, cut with a variety of restriction enzymes and probed with a near-full-length (1,450-bp) human liver arginase cDNA clone, detected no gross gene deletions. Loss of a TaqI cleavage site was identified in three individuals: in a homozygous state in a Saudi Arabian patient at one site, at a different site in homozygosity in a German patient, and in heterozygosity in a patient from Australia. The changes in the latter two were localized to exon 8, through amplification of this region by PCR and electrophoretic analysis of the amplified fragment after treatment with TaqI; the precise base changes (Arg291X and Thr290Ser) were confirmed by sequencing. It is interesting that the latter nucleotide variant (Thr290Ser) was found to lie adjacent to the TaqI site rather than within it, though whether such a conservative amino acid substitution represents a true pathologic mutation remains to be determined. We conclude that arginase deficiency, though rare, is a heterogeneous disorder at the genotypic level, generally encompassing a variety of point mutations rather than substantial structural gene deletions.     

Extracting message inter-departure time distributions from the human electroencephalogram

The complex connectivity of the cerebral cortex is a topic of much study, yet the link between structure and function is still unclear. The processing capacity and throughput of information at individual brain regions remains an open question and one that could potentially bridge these two aspects of neural organization. The rate at which information is emitted from different nodes in the network and how this output process changes under different external conditions are general questions that are not unique to neuroscience, but are of interest in multiple classes of telecommunication networks. In the present study we show how some of these questions may be addressed using tools from telecommunications research. An important system statistic for modeling and performance evaluation of distributed communication systems is the time between successive departures of units of information at each node in the network. We describe a method to extract and fully characterize the distribution of such inter-departure times from the resting-state electroencephalogram (EEG). We show that inter-departure times are well fitted by the two-parameter Gamma distribution. Moreover, they are not spatially or neurophysiologically trivial and instead are regionally specific and sensitive to the presence of sensory input. In both the eyes-closed and eyes-open conditions, inter-departure time distributions were more dispersed over posterior parietal channels, close to regions which are known to have the most dense structural connectivity. The biggest differences between the two conditions were observed at occipital sites, where inter-departure times were significantly more variable in the eyes-open condition. Together, these results suggest that message departure times are indicative of network traffic and capture a novel facet of neural activity.     

One result in the task of simulating a human electroencephalogram

The problem is discussed concerning possible loss of dynamic stability of the source of man's alpha-rhythm, as well as one of psychoneurological aspects of this phenomenon. With the aim of modeling man's EEG on animals an experimental criterion is suggested which makes it possible to state that definite spectral peak of animal EKoG cannot serve as a model for studying the properties of man's alpha-rhythm.     

Influence of geophysical factors on the parameters of the human electroencephalogram

It has been shown that cerebral processes are characterized by fine physiological meteosensitivity. Under ordinary conditions, this manifests itself in correlations between human EEG parameters and the geophysical factors: wind regime, temperature, atmospheric pressure, and relative air humidity. The biometeorological properties of EEG rhythms of a human irrespective of age increase with their quickening in the order delta — theta — alpha — beta. The less the background expressiveness of the neurodynamic process, the sharper its meteosensitivity till a certain limit. The lack of a component of one neurodynamic process is filled up by the functional component of another.     

A genetic linkage map of the human genome

We report the construction of a linkage map of the human genome, based on the pattern of inheritance of 403 polymorphic loci, including 393 RFLPs, in a panel of DNAs from 21 three-generation families. By a combination of mathematical linkage analysis and physical localization of selected clones, it was possible to arrange these loci into linkage groups representing 23 human chromosomes. We estimate that the linkage map is detectably linked to at least 95% of the DNA in the human genome.