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At least 19 recordsLinked to original sources
PubMed1981

Topographical distribution of delta rhythms during sleep: evolution with age.

This study concerns the evolution of slow EEG activities (delta rhythms) and their topographical distribution during 31 night sleep records of 27 control subjects whose ages ranged from 1 month to 27 years. A system of data processing allows the representation of continuous changes in 8 derivations of the power of 0.5--4.5 c/sec waves. The obtained curves, whose respective magnitudes depend on the chosen montage, parallel the sleep cycles of the classical hypnogram. They do not clearly differentiate NREM sleep stages, but show a progressive increase of delta rhythm power with the deepening of NREM sleep. Moreover, measurement of the magnitude to these curves allows comparisons between the different channels in a given record and between different recordings. With the referential setting used in this study the topographical organization of the occipital, parietal and central curves proved occipital, parietal and central curves proved remarkably consistent in all subjects. The general magnitude of these curves decreased with age while that of frontal curves slightly increased. The right parietal curves were of greater magnitude than the left in every record obtained from children aged 2--5 years. The changes with age, and the intra- and interindividual differences are discussed. The data suggest hypotheses about the importance of NREM sleep in developmental processes.

Adolescent↗
PubMed1996

Projection cells and interneurons of the lateral and basolateral amygdala: distinct firing patterns and differential relation to theta and delta rhythms in conscious cats.

To study relations between the basolateral (BL) amygdaloid complex and major electroencephalogram (EEG) rhythms of the entorhinal cortex (delta and theta), neurons of the lateral and BL nuclei were recorded in conscious cats. An essential task to this end was to obtain criteria allowing the identification of projection cells and interneurons. BL projection cells, identified by their antidromic response to parahippocampal stimuli, generated stereotyped high-frequency bursts (2-4 spikes at 140-250 Hz), which repeated at low rates. Projection cells of the lateral nucleus were virtually silent, but their presence was disclosed by cortical-evoked responses. In both nuclei, the firing rates and/or responsiveness of projection cells increased from waking to slow-wave sleep (S). In contrast with projection cells, presumed interneurons discharged at high rates (approximately 10-15 Hz) and displayed various discharge patterns ranging from tonic to phasic. The bipartite classification of BL neurons on the basis of their discharge patterns and synaptic responses was supported by the differential relation existing between EEG rhythms and the activity of the two cell types. Indeed, fast-firing and bursting cells of the BL nucleus tended to fire on opposite phases of the delta oscillation of S and entorhinal theta oscillation of paradoxical sleep. The unusual state-related changes in activity displayed by lateral and BL neurons point to functional similarities between the amygdala and hippocampus. This idea is supported by the presence of coherent theta oscillations in the amygdala-hippocampal circuit that might favor the emergence of recurring time windows when synaptic interactions will be facilitated in this limbic network.

Amygdala↗
PubMed1981

[Peculiar and random activity in Macaca: delta rhythm at the vertex].

Despite the fact that waking and sleeping EEG activities are well known in cercopithecinae, a striking random activity was noted in 3 macaque species: M. mulatta, M. fascicularis, M. nemestrina. It occurred in bursts of monophasic slow waves (250-400 msec) at 3/sec (2.5-4/sec, according to the moment and the individual at 50-480 microV amplitude, with a waxing and waning aspect. The duration was 2-24 sec. It predominated along the midline, in the precentral and supplementary motor areas; hence its name, the delta vertex rhythm. It occurred either isolated or several times within the same REM or waking episode. In some monkeys it was more or less frequent on different recording nights; however, in other monkeys it could be totally absent. Its mean total duration, for a 12 h recording, was 0.45% for M. mulatta and 0.065% for M. fascicularis. No significant correlations were found between its occurrence and the age, sex, the moment of occurrence of eye movements and sawtooth waves.

Animals↗
PubMed1980

System for studying the topography of delta rhythm during sleep: further development.

A hybrid system for treatment of all-night sleep EEG records is described, which leads to the representation of sleep cycles by the continuous variation of the amplitude in a given frequency band. This system constitutes the development of a previous purely analogic one. The addition of a micro-processor and of a small computer renders the system far more flexible and easier to use. The results stored on tape are available for further treatments.

Analog-Digital Conversion↗
PubMed1979

System for studying the delta rhythm during sleep and its topographical amplitude distribution.

An analogue system of processing all-night sleep EEG records which leads to the representation of sleep cycles by the continuous variation of the amplitude parameter in a given frequency band is described. The curves obtained are analogous to those resulting from more sophisticated computerized analyses. The cycles which they outline are in good concordance with those of the classic hypnogram. Moreover, the simplicity and the rapidity of the processing easily allow its application to multiple EEG channels. A topographical discrimination of the amplitude parameter during sleep was observed in normal subjecttion. The results obtained are illustrated in the case of a normal child and a young normal adult.

Adult↗
PubMed1996

Functional reorganization in thalamocortical networks: transition between spindling and delta sleep rhythms.

Thalamic reticularis, thalamocortical, and cortical cells participate in the 7-14-hz spindling rhythm of early sleep and the slower delta rhythms of deeper sleep, with different firing patterns. In this case study, showing the interactions of intrinsic and synaptic properties, a change in the conductance of one kind of cell effectively rewires the thalamocortical circuit, leading to the transition from the spindling to the delta rhythm. The two rhythms make different uses of the fast (GABAA) and slow (GABAB) inhibition generated by the thalamic reticularis cells.

Cerebral Cortex↗
PubMed1983

Cyclic variation of integrated delta components during nocturnal sleep in mentally retarded children.

The cyclic variation of the integrated delta component in 80 mentally retarded children (from 2 months to 12 years of age) was studied throughout nocturnal sleep, and the following results were obtained. In 62 out of 80 subjects the high integrated delta rhythm power was noted in sleep EEG. In 11 out of the 80, low integrated delta rhythm power was found. In the remaining 7 subjects, no integrated delta rhythm power was found throughout nocturnal sleep. A significant increase in abnormal clinical EEG was found in subjects without delta rhythm power as compared to those with high delta rhythm power. A significant decrease in DQ was found in the subjects without delta rhythm power as compared to those with high and low delta rhythm powers.

Brain↗
PubMedDate not supplied

Rhythmic delta-frequency activities in the nucleus accumbens of anesthetized and freely moving rats.

In urethane-anesthetized rats, a membrane potential oscillation (MPO) of up to 30 mV and 0.5-2 Hz (delta frequency range) was found in neurons of the nucleus accumbens. The membrane potential oscillations were of similar frequency and reversed in phase to the extracellular EEG of about 0.5 mV. In freely moving rats, a rhythmic delta EEG of 0.5-3 Hz was found in the nucleus accumbens, and it was of highest amplitude and regularity during awake immobility and face washing, less regular during slow wave sleep, and of the lowest amplitude during body and head movements and rapid eye movement sleep. The behavioural relation of the accumbens EEG was not critically affected after amphetamine, haloperidol, and parachlorophenylalanine, which depleted serotonin, although the accumbens EEG during awake immobility was less regular after blocking muscarinic cholinergic receptors by atropine sulfate. However, stimulation of the ventral tegmental area suppressed the accumbens delta membrane potential oscillations and EEG, and this effect was antagonized by haloperidol, suggesting that endogenous dopamine release may suppress the accumbens delta rhythm. It was concluded that the delta rhythm in the nucleus accumbens may represent a state of bilateral synchrony among accumbens neurons that is perhaps characteristic of an idling system, while desynchronization of the delta rhythm may occur closely with motor action.

Anesthesia↗
PubMed1979

[The 4 c/sec rhythm (case report and differential diagnosis) (author's transl)].

Report on a female patient with a 3 c/sec rhythm. The 3 c/sec rhythm is a special case of the 4 +/- 1 c/sec rhythm. The characteristics of this variant are reviewed in tabulated form. The differential diagnosis has to take into consideration other slow posterior rhythms like the so-called delta-parenrhythmia and delta-parenrhythmia, abortive forms of spike and wave complexes and the abnormal delta-rhythms and sinusoidal delta-rhythms in the infantile EEG.

Adult↗
PubMed1987

Rhythmic pineal-hypophyseal-adrenal intermodulations ex vivo.

To assess circadian and circaseptan rhythmic intermodulation, female mice, kept on regimens of 12 hr light (L) alternating with 12 hr of darkness (D) (LD 12:12) were sampled for 1-13 days at six circadian stages. Pineals were removed and homogenized with 0.9% NaCl. Adenohypophyses were bisected and incubated in Krebs-Ringer buffer (KRb) and/or with 10(-7) M melatonin (Mt). Adrenals were bisected and incubated with KRb, with 10(-7) M Mt, with 0.05 IU of ACTH 1-17 (Sy; Hoechst, Italy), or with Sy + 0.025 ml of the aqueous pineal homogenate (APH). ACTH and prolactin (PRL) in adenohypophysis incubation fluid were determined by radioimmunoassay (RIA), and corticosterone in adrenal incubation fluid was determined by RIA or by a fluorometric method. By this chronobiologic approach, time series were collected systematically in the search for predictable variability. Once these series reveal an algorithmically formulatable pattern, with a waveform validated by inferential statistical means, they are graded in terms of complexity as alpha, beta, gamma, and delta rhythms. Spontaneously (alpha-) rhythmic along the 24-h scale is the corticosterone produced by bisected adrenal glands incubated with KRb only, and the Mt content of the APH, in keeping with earlier work. Reactively (beta-) rhythmic is the response, again along the 24-hr scale, of the adrenal to Sy or Mt and the response of the anterior pituitary to Mt at different circadian times. Modulatory (gamma and delta) rhythms characterize the Mt effect on the (beta-rhythmic) adrenal stimulation by Sy. Chronomodulations thus emerge as more or less complete sequences of a decrease, no effect and/or increase; or, rather, as an attenuation, no effect and/or amplification by the pineal, of the pituitary effect upon the adrenal. Linear least-squares rhythmometry, mostly single cosinors, describes and quantifies circadian (alpha, beta, and gamma) and infradian (delta) rhythms in the original series and in the differences in responses [beta - alpha] and [gamma - beta] (P less than 0.001 in each case). These spontaneous alpha, response beta, modulatory gamma, and frequency-divided delta rhythms reveal a collateral neuroendocrine hierarchy, characterized by the pineal feedsideward phenomenon, as a feature of interactions recurring with circadian and infradian frequencies.

Adrenocorticotropic Hormone↗
PubMed1996

Coupled slow and delta oscillations between cuneothalamic and thalamocortical neurons in the chloralose anesthetized cat.

Simultaneous recordings were obtained from cuneothalamic (extracellular) and thalamocortical (intracellular) cells in chloralose anesthetized cats. It was found that cuneothalamic neurons present slow rhythmicity (0.1-1 Hz) tightly coupled to slow oscillations of thalamocortical neurons. This coupling was not due to a direct synaptic linkage but rather produced by other (s) structure (s) probably the cortex. Furthermore, the cuneothalamic neurons also showed delta rhythms (1-4 Hz) coherently oscillating with the delta rhythms of thalamocortical cells which suggests that these rhythms are more widespread than previously thought, and may be a general phenomenon characterizing quiet sleep in multiple structures.

Animals↗
PubMed1994

Childhood absence epilepsy.

BACKGROUND: Childhood absence epilepsy (CAE) is a relatively rare form of idiopathic generalized epilepsy, occurring in previously normal children with a strong genetic predisposition. The annual incidence of CAE has been estimated at 6.3/100,000 to 8/100,000 children aged 0-15 years. METHODS: Medical and electroencephalographic records of 50 Chinese children with CAE were reviewed. RESULTS: There were 22 males and 28 females. The age of onset ranged from 3 to 12 years with a mean of 6.9 +/- 2.4 years. Six children (12%) had positive familial epileptic history and 11 patients (22%) had a past history of febrile convulsion. Electroencephalographically, there were posterior delta rhythm (6/50), frontocentral (1/50), and centrotemporal (1/50) spikes in addition to the characteristic 3 Hz spike and wave complex. All patients received regular or irregular treatment with valproate. Sixteen patients (32%) evolved to generalized tonic-clonic seizure (GTCS) with a mean of 2.1 +/- 1.6 years of lag from stopping valproate. The patients with GTCS had significant late onset of age, a longer active period, and longer treatment duration than those without GTCS (p < 0.01). There were significantly more patients with irregular treatment evolving to GTCS than those with regular treatment (p < 0.01). None of the patients with posterior delta rhythm evolved to GTCS. CONCLUSIONS: Regular treatment with valproate is the modality of choice in the management of CAE. Posterior delta rhythm seems to be a good prognostic factor electroencephalographically.

Child↗
PubMed1992

Digital period analysis of sleep EEG in depression.

The period-analyzed sleep electroencephalogram (EEG) was compared in a group of 9 depressed outpatients and 9 age-matched normal controls. Both groups showed rhythms in beta, delta, and theta activity with an approximately 90-min period. The phase and coherence between fast and slow frequency EEG measures, however, differed significantly in the two groups. Beta and delta rhythms were less coherent in the depressed outpatient sample. The control group showed higher coherence and a strong coupling of beta and delta activity. These preliminary data suggest that depression may be associated with some degree of ultradian rhythm disturbances though periodicity is unaffected.

Activity Cycles↗
PubMedDate not supplied

Effects of a number of short peptides isolated from the brain of the hibernating ground squirrel on the EEG and behavior in rats.

Intracerebroventricular administration of the peptides kyotorphin (Tyr-Arg), neokyotorphin (Thr-Ser-Lys-Tyr-Arg), and Asp-Tyr at doses of 4 and 8 micrograms altered the behavior of rats in a manner similar to that seen after similar administration of brain fractions from hibernating ground squirrels (Citellus undulatus), which contained these peptides; there were increases in orientational reactions, increases in the frequency of stereotypical scratching movements, grooming, yawning, hiccuping, and sneezing. Animals became drowsy after 15-20 min. Peptides and brain fractions also had similar effects on the EEG of rats. Brain fractions reduced theta and alpha rhythms and enhanced delta and beta frequencies. Increases in delta waves were seen with all peptides (a 4-microgram dose of kyotorphin produced alternating increases and reductions in the delta rhythm). Inhibition of theta and alpha rhythms after administration of Asp-Tyr and kyotorphin was more transient than after brain fractions. Increases in beta frequencies were seen only after administration of 8 micrograms of Asp-Tyr, the smaller dose not producing this effect.

Analgesics↗