Correlation between level of aggressiveness of personality and characteristics of EEG frequency components

In a group of 80 adults of both sexes, we studied the correlation between the characteristics of aggressiveness of the individual (diagnosed using the Buss-Durkee questionnaire) and parameters of the frequency components (rhythms) of EEG recorded in the resting state from leads C3 and C4 according to the 10–20 system. Despite the natural high interindividual variability, the higher spectral powers of nearly all EEG frequency components (δ-, θ-, α-, and β rhythms) and coefficient of reactivity of the α rhythm corresponded in general to lower indices on the scales of the Buss-Durkee questionnaire and smaller values of the index of aggressiveness and index of hostility. These correlations probably reflect a significant dependence of both characteristics of aggressiveness of personality and amplitude parameters of the EEG rhythms on hereditary factors. Both these aspects of the neurodynamic constitution of the individual are to a significant extent determined by the specificity of organization and functioning of a few neurotransmitter (in particular, aminergic) and neurohumoral systems. Neirofiziologiya/Neurophysiology, Vol. 38, Nos. 5/6, pp. 448–457, September–December, 2006.     

The seasonal characteristics of the circadian rhythm of hypoxic resistance and convulsive resistance]

Hypoxic and convulsive resistances have daily rhythms, the pattern of which depends on the year season. Latent period of occurrence of epileptic seizures and time of life at the "height" of 11,000 m above the sea level undergo similar changes in autumn and spring. In winter minimal similarity between daily dynamics of each of these resistances and analogous ones in other seasons is observed, but rhythms of tolerance to hypoxia are maximally synchronized with the rhythms of convulsive resistance. In autumn hypoxic and convulsive resistances are minimal. Maximums of these indices are observed in different seasons: for tolerance to hypoxia it is summer, for convulsive resistance--spring.     

Ultradian activity rhythms in large groups of newly hatched chicks (Gallus gallus domesticus)

A clutch of young chicks housed with a mother hen exhibit ultradian (within day) rhythms of activity corresponding to the brooding cycle of the hen. In the present study clear evidence was found of ultradian activity rhythms in newly hatched domestic chicks housed in groups larger than natural clutch size without a mother hen or any other obvious external time-keeper. No consistent synchrony was found between groups housed in different pens within the same room. The ultradian rhythms disappeared with time and little evidence of group rhythmicity remained by the third night. This disappearance over time suggests that the presence of a mother hen may be pivotal for the long-term maintenance of these rhythms. The ultradian rhythm of the chicks may also play an important role in the initiation of brooding cycles during the behavioural transition of the mother hen from incubation to brooding. Computer simulations of individual activity rhythms were found to reproduce the observations made on a group basis. This was achievable even when individual chick rhythms were modelled as independent of each other, thus no assumptions of social facilitation are necessary to obtain ultradian activity rhythms on a group level.     

Temporal relationships of 21 physiological variables in horse and sheep

Daily or circadian oscillation has been documented in a variety of physiological and behavioral processes. Although individual variables have been studied in great detail, very few studies have been conducted on the temporal relationships between the rhythms of different variables. It is not known whether the circadian pacemaker generates each and every rhythm individually or whether most rhythms are simply derived from a few clock-controlled rhythms. As a first step in elucidating this issue, 21 physiological variables were recorded simultaneously in horse and sheep. The results indicated that, in both species, different variables exhibit different degrees of daily rhythmicity and reach their daily peaks at different times of the day. The variables exhibiting strongest rhythmicity were locomotor activity, rectal temperature, and plasma concentrations of melatonin and glucose. Comparison of rhythmicity and acrophase in the various rhythms allowed inferences to be made about mechanisms of causation.     

Effect of Changing the Light/Dark Schedule, the Time of Onset of the Light or Dark Period, or the Daylength, on Rhythms of Epidermal Cell Proliferation

Rhythms of labeling and mitotic indices were studied in the hindlimb epidermis of the anuran tadpole Rana pipiens under different light/dark (LD) cycles and daylengths in order to examine the role of the various parameters of the lighting regimen in setting the periods of the rhythms and the timing of the cell proliferation peaks. Altering the time of, or inverting, the 12 h light period on a 24 h day resulted in phase shifting of basically bimodal circadian rhythms with peaks in the light and dark. Thus the cell proliferation rhythms were entrained to the LD cycle. These rhythms also entrained to noncircadian schedules since they lengthened on a 15L : 15D cycle and shortened on a 9L : 9D cycle, although the bimodal characteristic of a peak in the light and a peak in the dark remained. Studies of 18L: 6D and 6L : 18D cycles in which either the time of onset of light or dark was changed relative to the 12L: 12D control indicated that the onset of dark may regulate the timing of the labeling index peaks while the onset of light may determine the time of occurrence of mitotic index peaks. Control of the timing of labeling and mitotic index peaks by different parameters of the LD cycle suggests a mechanism for cell cycle regulation by the environmental lighting schedule. Analysis of the rhythms on all the cycles studied suggested that labeling index rhythms equal the length of, or twice the length of, the dark period. Mitotic index rhythms equal the daylfength or a multiple of the length of the dark period.     

Structure of autorhythmical activity of contractile systems

In the autorhythmical activity underlying many visceral and in early ontogenesis also somatomotor systems, three kinds of rhythms are to be distinguished: basic, reflecting activity of individual organs and of systems of organs, the secondary ones representing result of the frequency and amplitude modulation of the basic rhythms, and the rhythmical periodic activity whose distinguishing feature is alternation of the activity and rest phases. Each kind has principally different frequency characteristics, different organization and localization of sources. The frequency of basic rhythms is determined by the generator inserted into the system. It serves an individual characteristics of the current state of function of the organ, the degree of maturity of its motor apparatus. The secondary rhythm and the rhythm of the periodic activity cycles are provided by oscillatory processes common to the whole organism. Universality of these rhythms promotes integration of functions.     

Circannual and Circa-Hemiannual Rhythms of Basal and Stimulated Gastric Secretion in Conscious Cats

Conscious cats equipped with a gastric fistula and a denervated Heidenhain pouch were submitted to weekly measurements of the basal and pentagastrin-stimulated gastric secretion for 1 to 14 years. Rhythms of basal secretion were documented in 37 cats for the group studies, in 25 cats only for the individual studies which required at least whole year data. Twelve-month or 6-month rhythms were detected for each variable studied, i.e. volume, acid, pepsin, fucose and uronic acid outputs in the group studies, with peaks for volume, acid and pepsin in Winter, peaks for uronic acid in Spring and Fall indicating different rhythms for oxyntic, chief and mucous cells. Individual studies detected rhythms in 25% of the analyses, and demonstrated male and female and cat to cat differences. Spectral analysis in 3 cats confirmed the differences in the individual rhythms with prominent peaks differing from 365 days in 50% of the cases. Chronopharmacological responses to pentagastrin were documented for volume, acid and pepsin outputs in 5 male and 6 female cats. Group analysis detected a Winter acrophase for volume and acid secretion and a Summer acrophase for pepsin secretion. Analysis of the stimulated response data showed interindividual variation but a higher percentage of detection for rhythms, i.e. 38% for all variables and 50% for pepsin secretion. Different rhythms in acid and pepsin secretion documented in individual studies could provide the basis of a better understanding of the discrepancies reported in the literature concerning the seasonal incidence of peptic ulcer disease.     

Circannual and Circa-Hemiannual Rhythms of Basal and Stimulated Gastric Secretion in Conscious Cats

Conscious cats equipped with a gastric fistula and a denervated Heidenhain pouch were submitted to weekly measurements of the basal and pentagastrin-stimulated gastric secretion for 1 to 14 years. Rhythms of basal secretion were documented in 37 cats for the group studies, in 25 cats only for the individual studies which required at least whole year data. Twelve-month or 6-month rhythms were detected for each variable studied, i.e. volume, acid, pepsin, fucose and uronic acid outputs in the group studies, with peaks for volume, acid and pepsin in Winter, peaks for uronic acid in Spring and Fall indicating different rhythms for oxyntic, chief and mucous cells. Individual studies detected rhythms in 25% of the analyses, and demonstrated male and female and cat to cat differences. Spectral analysis in 3 cats confirmed the differences in the individual rhythms with prominent peaks differing from 365 days in 50% of the cases. Chronopharmacological responses to pentagastrin were documented for volume, acid and pepsin outputs in 5 male and 6 female cats. Group analysis detected a Winter acrophase for volume and acid secretion and a Summer acrophase for pepsin secretion. Analysis of the stimulated response data showed interindividual variation but a higher percentage of detection for rhythms, i.e. 38% for all variables and 50% for pepsin secretion. Different rhythms in acid and pepsin secretion documented in individual studies could provide the basis of a better understanding of the discrepancies reported in the literature concerning the seasonal incidence of peptic ulcer disease.     

Topographic characteristics of cortex activity in delta-, alpha2-, and gamma2- frequency bands related to social creativity

Social creativity-related topographic changes of the delta, alpha2, and gamma2 power were studied using 19-channel EEG. Originality and fluency indices of social thinking were evaluated on basis of specially developed 'divergent' task solution that stimulated different interpretations of social scenes; complex visual stimuli (architectural building) were used as control task. 'Divergent' task performing was characterized by both the greater power of the delta and alpha2 rhythms mostly in the right hemisphere and widespread increase in the gamma2 power as compared with the control task. Positive correlations between delta and gamma2 rhythms in baseline condition were revealed in the fronto-parietal cortex, and this relationship between low- and high-frequency oscillations while 'divergent' task performing was found in the right posterior cortex. Special topographic patterns of delta and gamma2 activity as predictors of social creativity were obtained using multiple regression analysis. These patterns can be interpreted as EEG correlates of a summation of endogenous and exogenous components of social thinking.     

Interrelations between Peculiarities of the Motivational Sphere of a Personality and Characteristics of the Current EEG

In a group of 70 adult subjects of both sexes, we estimated the levels of the need for achievement and its motivation (interpreted as generalized characteristics of the state of the motivational sphere of a personality and diagnosed using questionnaires of Orlov and Mehrabian) and examined the correlations of these estimates with spectral powers (SPs) of the frequency components (rhythms) of the current background EEG (С3 and С4 leads according to the 10–20 system). Despite the fact that naturally high interindividual variability exists, high estimates of the need for achievement correlated with medium values of the SPs of most EEG frequency components (δ, θ, α, and β₁ rhythms), low SPs of the β₂ and γ rhythms, and higher values of the coefficient of reactivity (CR) of the α rhythm. A high level of the need for achievement corresponded to higher SPs of the θ and γ rhythms and high CR of the α rhythm, a medium SP of this EEG component, and lower SPs of the δ and β rhythms. The coefficient of interhemisphere asymmetry of the α rhythm was the highest at low values of the studied psychological indices. Interrelations that we found in our study can be explained as follows: both the characteristics of the need for achievement and motivation typical of a certain personality and the amplitude parameters of the EEG rhythms observed in this individual depend significantly on genetically determined factors (in particular, on neurochemical ones). These peculiarities of neurodynamic constitution of the individual are, to a considerable extent, due to the specificity of organization and functioning of a few neurotransmitter (aminergic, in particular) and neurohumoral systems. Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 61–69, January–February, 2009.     

Desynchronization of oral temperature, pulse and performance circadian rhythms in shift working Indian nurses.

Circadian time structure in shift working Indian nurses was studied. In shift workers desynchronization between circadian rhythms in different physiological variables was observed. Circadian amplitudes of oral temperature, pulse and random add speed rhythms decreased significantly in shift workers as compared to control subjects. Circadian mesors of performance rhythms increased significantly in shift workers indicating that the time taken by them was more for performing the tasks. It can be concluded that the subjects studied herein are intolerant to shift work and amplitude decrement may be considered as a chronobiologic index to determine the tolerance of individual workers to shift work.     

EEG Correlates of the Psychological Adaptation Potential of a Personality

In a group of 68 adults of both sexes, we examined correlations between estimates of the psychological adaptability of an individual (diagnosed using a multilevel personality questionnaire, MPQ) and spectral powers, SPs, of the frequency components (rhythms) of background EEG recorded in the resting state (leads C3 and C4 according to the 10–20 system). Despite high individual variability within the group, indices by the scale “communicative potential” demonstrated significant correlation with the SP of the θ rhythm, while estimates of the moral normativity correlated with the SPs of the α and β1 rhythms. Subgroups of the persons classified according to the level of the integral adaptation capability (personality’s adaptation potential) differed from each other in the mean estimates of interhemisphere asymmetry of the α rhythm; this index was higher in subjects with the medium/high level of adaptability. The correlations observed are, most probably, determined by the fact that both the level of psychological adaptability of the personality and the EEG amplitude parameters depend significantly on genetic (neurochemical, in particular) factors. Such peculiarities of the neurodynamic constitution of the individual are probably determined, to a considerable extent, by the specificities of organization and functioning of a few neurotransmitter (aminergic, in particular) and neurohumoral systems.     

Neural correlates of individual differences in circadian behaviour

Daily rhythms in mammals are controlled by the circadian system, which is a collection of biological clocks regulated by a central pacemaker within the suprachiasmatic nucleus (SCN) of the anterior hypothalamus. Changes in SCN function have pronounced consequences for behaviour and physiology; however, few studies have examined whether individual differences in circadian behaviour reflect changes in SCN function. Here, PERIOD2::LUCIFERASE mice were exposed to a behavioural assay to characterize individual differences in baseline entrainment, rate of re-entrainment and free-running rhythms. SCN slices were then collected for ex vivo bioluminescence imaging to gain insight into how the properties of the SCN clock influence individual differences in behavioural rhythms. First, individual differences in the timing of locomotor activity rhythms were positively correlated with the timing of SCN rhythms. Second, slower adjustment during simulated jetlag was associated with a larger degree of phase heterogeneity among SCN neurons. Collectively, these findings highlight the role of the SCN network in determining individual differences in circadian behaviour. Furthermore, these results reveal novel ways that the network organization of the SCN influences plasticity at the behavioural level, and lend insight into potential interventions designed to modulate the rate of resynchronization during transmeridian travel and shift work.     

Biological and psychological rhythms: An integrative approach to rhythm disturbances in autistic disorder

Biological rhythms are crucial phenomena that are perfect examples of the adaptation of organisms to their environment. A considerable amount of work has described different types of biological rhythms (from circadian to ultradian), individual differences in their patterns and the complexity of their regulation. In particular, the regulation and maturation of the sleep–wake cycle have been thoroughly studied. Its desynchronization, both endogenous and exogenous, is now well understood, as are its consequences for cognitive impairments and health problems. From a completely different perspective, psychoanalysts have shown a growing interest in the rhythms of psychic life. This interest extends beyond the original focus of psychoanalysis on dreams and the sleep–wake cycle, incorporating central theoretical and practical psychoanalytic issues related to the core functioning of the psychic life: the rhythmic structures of drive dynamics, intersubjective developmental processes and psychic containment functions. Psychopathological and biological approaches to the study of infantile autism reveal the importance of specific biological and psychological rhythmic disturbances in this disorder. Considering data and hypotheses from both perspectives, this paper proposes an integrative approach to the study of these rhythmic disturbances and offers an etiopathogenic hypothesis based on this integrative approach.     

Ultradian and Asymmetric Rhythms of Hemispheric Processing Speed

Daily changes in cognitive performance have been documented, both in time of day/effect paradigm studies and in time‐isolation studies. However, in both types of studies, phenomena such as the “post‐lunch dip” have been found that were difficult to explain in terms of theoretical backgrounds. These phenomena may suggest ultradian rhythms in cognitive performance. A number of studies have also shown ultradian and asymmetric rhythms in activity indices of the brain hemispheres. The aim of this study was to test three hypotheses: the first two assumed that there is a significant ultradian frequency in a component of the endogenous rhythm of processing speed, and the third assumed that the ultradian endogenous rhythms of the processing speed (encoding and recognition) of stimuli addressed to the left brain hemisphere differ in period length from those addressed to right hemisphere. During a 24 h constant‐routine experiment, the memory performance of 30 participants was measured eight times (every 2.5–3 h), starting at 06:30 h. Parallel sets of words and pictures were shown to subjects in a random order in either the left or the right visual field on a computer screen. The participants pressed one of two buttons in response to the picture or word, or when answering a question concerning the meaning of a presented stimulus. Cosinor analysis was applied to individual time series data. Two significant ultradian components were found in a majority of the time series. Dominant periods were analyzed using three factor ANOVA. The results showed an asymmetry between both hemispheres in the frequency of ultradian rhythms in encoding speed.     

Effect of geomagnetic activity on the rhythm of resistance of rats to hypoxia

The resistance of male Wistar rats to acute hypoxia was estimated from the lifetime at an "altitude" of 11.5 km above sea level from 13 to 21 p.m. and in different seasons of a year. Identical types of rhythms (circaseptan, circasemiseptan, infradian, circadian, and ultradian) of geomagnetic activity and lifetime were revealed. It was found that the periods of basal rhythms either coincide or are multiple. It was shown that the rhythms of geomagnetic activity (including nonbasal rhythms) affect lifetime rhythms (especially ultradian rhythms). As the periods of the rhythms decrease, the number of rhythms for both parameters increase (ultradian rhythms are most numerous), and relative differences in the values of periods (they are minimal for ultradian rhythms) and the amplitudes of rhythms decrease.     

Use of antisense oligodeoxynucleotides to study biological rhythms

Perturbation analysis has been crucial in the study of biological rhythms. Antisense technology provides investigators with new means to alter the internal milieu of the circadian clock itself. Practical aspects of the method and the theoretical background are presented in sufficient detail to enable others to design appropriate antisense oligodeoxynucleotides and use them for research purposes. This strategy will contribute substantially to the understanding of the influence of individual genes on rhythms in hormone secretion, metabolism, and behavior.     

Chronic Administration of Imipramine and Lithium Changes the Phase-Angle Relationship Between the Activity and Core Body Temperature Circadian Rhythms in Rats

Evidence suggests that there is an association between the pathophysiology of depression and a disturbance of circadian rhythms. Accordingly, attention has focused on the possible effects of antidepressants on circadian rhythms. In the present study, we examined the effects of chronic administration of two clinically effective antidepressant agents, imipramine and lithium, on several circadian rhythms in the rat. Activity, core body temperature, and drinking rhythms were assessed in constant darkness (DD) and light-dark (LD) conditions. In DD, lithium significantly lengthened the circadian period of the activity, temperature, and drinking rhythms, while imipramine had no effect. In LD, both drugs significantly delayed the phase of the activity rhythm, but did not change that of the other two rhythms. As a result, the phase-angle differences between the activity and temperature rhythms significantly increased. Neither lithium nor imipramine produced any effect on the resynchronization of these rhythms after an 8-h delay in the LD cycle. These results indicate that although both drugs produced different effects on the circadian period of individual rhythms, both caused a relative phase advance of the temperature rhythm as compared to the activity rhythm, and this effect may be related to the similarity in their antidepressant effects. (Chronobiology International, 13(4), 251-259, 1996)     

Effect of continuous darkness on circadian morphological rhythms in pinealocytes of the Chinese hamster,Cricetulus griseus

Summary Effects of a short-term exposure to continuous darkness on 24-h morphological variations in pinealocytes in the superficial pineal of the Chinese hamster (Cricetulus griseus) were examined. Pinealocytes contained type-1, -2 and -3 synaptic ribbons (SR), which had a central dense structure showing rod-like, various and ring-like profiles, respectively, and the quantity of each type of SR was expressed by SR index. 24-h changes in the type-1 and type-3 SR indices persisted in darkness and thus may be endogenous in nature. As under alternating light and dark (LD) conditions, the type-2 SR indices were almost constant over a 24-h period under continuous darkness, but the indices were larger in animals under darkness than in those under LD conditions. The 24-h variations in the nuclear and cytoplasmic volumes were abolished after exposing animals to darkness for 7 days, suggesting that these rhythms may be regulated exogenously. The amount of condensed chromatin exhibited a circadian change; this rhythm persisted under darkness. The results suggest that 24-h variations in the nuclear and cytoplasmic volumes in pinealocytes of the Chinese hamster are regulated by mechanisms different from those controlling the rhythms in SR and chromatin, and that the changes in the nuclear and cytoplasmic volumes and chromatin are related to the change in synthetic activity of pinealocytes.     

Different circadian pacemakers control feeding and locomotor activity rhythms in European starlings

Summary In higher organisms, many physiological and behavioral functions exhibit daily variations, generated by endogenous circadian oscillators. It is not yet clear whether all the various rhythms that occur within an individual depend on one and the same pacemaker or whether different pacemakers are involved. To examine this question, the feeding and perch-hopping rhythms were measured in European starlings (Sturnus vulgaris) under light-dark cycles and continuous dim light. In dim light, the internal phase relationship between the feeding and perch-hopping rhythms changed systematically as a function of the circadian period, and the two rhythms could even dissociate and show different circadian periods in individuals with extremely long or extremely short circadian periods. Moreover, in some birds kept on lowamplitude light-dark cycles, the rhythm of feeding was synchronized 180° out of phase with the rhythm of locomotor activity. These results strongly suggest that in the European starling the feeding and locomotor activity rhythms are controlled by separate circadian pacemakers.