Modifications of Motor Asymmetry in Rats under the Influence of Low-Intensity Extra High-Frequency Electromagnetic Radiation in the Norm and under Stress Conditions

We studied modifications of motor asymmetry in rats with different motor lateralization (dextrals, sinistrals, and ambidextrals) induced by low-intensity extra high-frequency (EHF) electromagnetic radiation (EMR), hypokinetic stress, and their combination. It was found that the development of hypokinetic stress in rats induced by limitation of their mobility results in a considerable decrease of the coefficient of motor asymmetry (up to inversion of its sign); this can be related to a decrease in the resistivity to stressing and adaptability of the organism to the influence of external factors. The influence of EHF EMR on the animals under conditions of both normal and limited motor activity resulted in an increase in the index of motor lateralization in animals of all phenotypic groups under study; probably, this helped to increase the adaptive capabilities of the organism. Neirofiziologiya/Neurophysiology, Vol. 37, No. 2, pp. 164–168, March–April, 2005.     

Interhemisphere asymmetry of hippocampus and neocortex in correlates of active and passive behavioural strategy in negative emotional situations

The interhemisphere interaction of neurons in bilateral derivations from parietal and sensomotor areas of neocortex and the area CA1 of hippocampus were studied in rabbits with active and passive behavioural strategy in the open field by plotting histograms of crosscorrelation. In passive animals, there was asymmetry in bilateral neuronal interaction: with right-sided dominance in the neocortex and with left-sided that--in the hippocampus. On the contrary, in active rabbits, the left-sided dominance was observed in the neocortex, and the lateralization was not revealed in the hippocampus. The brain laterality was reflected in motor asymmetry of animals in preferring left or right turns in the open field. Passive rabbits made relatively more left turns, and the active animals--right turns. Systemic administration of agonist GABA(B) receptors phenibut decreased behavioural responses to emotional stimuli and eliminated interhemisphere asymmetry observed usually in negative emotional situations. Thus the interhemisphere asymmetry of the neocortex and hippocampus is correlated with individual typological characteristics of animals and reflects the readiness to preferential forms of behavioural responses in active and passive rabbits.     

Functional Activity of the Sympathoadrenal System and Behavioral Indices of Rats: Changes Induced by Millimeter-Range Electromagnetic Radiation

We examined the ability of low-intensity millimeter-range (mmR) electromagnetic radiation (EMR) to modify the functional activity of the sympathoadrenal system (SAS) and the behavioral reactions in intact rats and rats with an experimentally induced stress reaction. Adaptation of the organism to mmR EMR has been shown to limit SAS activation; this is considered one of the mechanisms of the antistressor effect of such radiation.     

Asymmetry of the bioelectrical activity of the human brain at different levels of consciousness

Asymmetry of different human EEG indices was studied at different levels of consciousness. Subjects' self-reported changes in the content of consciousness: the intensity and quality of involuntary mental processes served as indicator of the level of consciousness. It was shown that a certain profile of EEG asymmetry corresponded to each the observed level of consciousness. In active state of consciousness, the connections in the high-frequency bands: beta-2 and gamma, were more pronounced in the left hemisphere of the brain. At the same time, transition of the focus of coherent connections to the right hemisphere was characteristic of the state of inhibition of "internal speech". The interhemisphere dynamics of autospectra amplitude and foci of coherent connections supports the notion that the character of interhemisphere asymmetry of the brain bioelectrical activity depends on its functional state.     

Intensity of Lipid Peroxidation in the Crystalline Lens of the Rabbit <Emphasis Type="Italic">Chinchilla brevicaudata</Emphasis> Exposed to Hypoxia and Radiation in the Prenatal Period

We address the redox homeostasis in the crystalline lens of the rabbit pups (aged 20 and 30 days) exposed to a combined effect of non-ionizing electromagnetic radiation (EMR) and hypoxia during their prenatal development. The intensity of lipid peroxidation (LPO) in the lens was in the focus of this study, being evaluated by a level of malondialdehyde (MDA), a final LPO product. It was established that prenatal exposure to 460-MHz non-ionizing EMR combined with hypoxia intensifies LPO. The obtained results allow some conclusions to be drawn about the mechanisms of antioxidant defense in relevant biological tissues. The necessity of further studies to prove the revealed tendencies is substantiated.     

EPR study of nitric oxide production in rat tissues under hypokinesia

EPR spectroscopy was used to study the intensity of nitric oxide (NO) production upon modeling 60-day progressive hypokinesia (restriction of motor activity) in rats and estimating the content of (DETC)₂-Fe²⁺-NO complexes in heart and liver tissues. In 30 days of hypokinesia, there was a 2–3-fold increase in tissue NO. Administration of a nonspecific inhibitor of NO synthases, L-NAME, to hypokinetic rats prior to measurement decreased their NO level even below the untreated control. Our results show that the intensified NO production in hypokinesia is mainly due to NO synthases, rather than to the nitrite reductase pathway.     

Interhemisphere asymmetry of the CSF dynamics and biomechanical properties of the skull

This investigation shows that both intracranial liquor circulation and skull biomechanical properties evaluated by its pliability (compliance) to intracranial pressure are characterised by marked interhemisphere asymmetry. The interhemisphere differences of cerebrospinal fluid mobility were evaluated by means of asymmetry coefficient (right/left ratio of liquor mobility) which was found to be 1.25-1.45 in healthy middle-age persons. For the skull pliability (compliance) the coefficient of hemispheric asymmetry was 0.75-0.95. These two hemisphere asymmetry coefficients are characterized by reciprocal relationships. These coefficients demonstrated no dominancy related to right/left hemisphere as well as no correlation with neurophysiological parameter. Functional tests (apnoea, hyperventilation, Stookey test) gave rise to significant changes of these coefficient values. At ageing, the magnitudes of these coefficients decreased. The spectral analysis of pulse waves of dopplerogram and rheoencephalogram reveals hemisphere asymmetry, too. It should be suggested that the interhemisphere asymmetry of the CSF dynamics and skull biomechanical properties is a special mechanism which contributes in the process of circulatory-metabolic support of brain activity.     

Physical criteria of pathological processes. II. Modulating role of functional interhemisphere asymmetry in forming and immune response in rheumatic diseases

The level of the brain permanent potential as a physiological criterion of the functional interhemisphere asymmetry, as well as immunological and biochemical characteristics of peripheral blood in patients with systemic rheumatic diseases were studied. It was found that the distribution of the characteristics of immune response in patients with different types of interhemisphere asymmetry. Significant differences were observed for average values of biochemical and immunological characteristics, their dispersions, as well as for the structure of relationships between the type of the interhemisphere asymmetry and immunobiochemical characteristics.     

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.     

Asymmetry of modifications of the electrical activity of the rat cortex induced by intraventricular injections of thyrotropin-releasing hormone

We studied modifications in the mass electrical activity of the cortex (ECoG) induced by injections of thyrotropin-releasing hormone (TRH) into the left or right lateral brain ventricle in rats kept under conditions close to free behavior. It was found that these effects are characterized by a significant interhemisphere asymmetry. We postulate that the pharmacological (in particular, antidepressive) effects of TRH are related to its ability to intensify inhibitory processes in the left cerebral hemisphere and activating processes in the right hemisphere.Neirofiziologiya/Neurophysiology, Vol. 36, Nos. 5/6, pp. 386–390, September–December, 2004.This revised version was published online in April 2005 with a corrected cover date and copyright year.     

Morphofunctional equivalents of the response of the adenohypophysis to limited physical activity

Morphofunctional equivalents of the anterior main adenohypophysis reaction to hypokinesia lasting for 8 +/- 1 and 23 +/- 2 days are demonstrated. The experiment has been performed on 26 non-inbred male dogs. Restriction of the motor activity for 8 days results in increasing amount of beta-basophilic and chromophobic adenocytes and in decreasing amount of acidophiles. The high activity of the adenocytes is accompanied with structural signs of decreasing functional possibilities of the adenohypophysis as a whole. The general amount of cellular-vascular contacts reduces and there is a tendency to decrease the whole area of the capillary lumens. The reaction of the adenohypophyseal elements at hypokinesia lasting for 23 days is demonstrated not only as changes of cellular composition, but also in appearance of a large amount of colloid-containing pseudofollicles, atypical chromophobes and in a slight discomplexion of adenocytes. In animals of this group certain signs of a relative activation of the gland are noted as compared to the first period of hypokinesia: increase in the cellular-vascular contacts and in the general area of the capillary lumens. "Increase" of the contact layer of the adenohypophysial epithelial trabecule and decrease in beta-basophils and acidophiles amount, observed during the second period of hypokinesia, make it possible to conclude that most of the adenocytes are in the phase of secrete excretion.     

Dynamics of oxidation stress markers during long-term antiorthostatic hypokinesia: A retrospective study

Nine volunteers aged 27 to 42 participated in an experiment with 370-day antiorthostatic hypokinesia at–5°C, and their blood serum samples were tested for the concentrations of lipid peroxidation (LPO) derivatives, including diene conjugates (DCs), malonic dialdehyde (MDA), and Schiff bases (SBs), and indices of the antioxidant defense system, including the tocopherol (TP) concentration and total antioxidant activity (AOA). The subjects were divided into two groups, which differed in physical training regimen and prophylaxis measures. Initial LPO steps were inhibited in both of the groups by 54–73% from day 50, while the level of SBs, which are final LPO products, decreased by 50–61% by day 230 and remained much the same up to the end of the experiment. The MDA and SB concentrations decreased by a factor of 1.6–2.3 during recovery. Total AOA decreased as an aftereffect during recovery to a level far lower than physiologically normal. Based on the significant inhibition of free-radical LPO throughout the experiment, long-term adaptation to simulated hypogravity was accompanied by a pronounced decrease in biological oxidation and caused severe stress. Substantial long-term readaptation stress developed during recovery after 370-day antiorthostatic hypokinesia, as was evident from the facts that the LPO activity was almost halved, TP concentration significantly increased, and the functional reserves of water-soluble antioxidants were exhausted. Lack of LPO activation was assumed to reflect adequate compensation in the subjects.     

Asymmetry of Motor Behavior of the Goldfish in a Narrow Channel

We studied swimming of goldfish fries about 3 cm long in a narrow channel by calculating the numbers of spontaneous turns on different sides. The ratio of fishes preferring to turn to the right vs to the left was 1.5:1.0, respectively; two-thirds of the fishes demonstrated an ambilateral behavior. Experiments with compulsory 10-min-long rotation of the fishes (clockwise around the longitudinal body axis for fishes preferring right-side turns and anticlockwise for fishes preferring left-side turns) showed that the behavioral asymmetry smoothed somewhat after such a procedure, and a greater number of the fishes became ambilateral in their preference to turn to one side or another. After a one- or two-day-long test, the initial asymmetry of motor behavior completely recovered. Compulsory rotation of similar fishes in the opposite direction exerted no influence on the asymmetry in the choice of the turning direction. Adaptation-induced training of the fishes (using fatiguing long-lasting vestibular stimulation) resulted in some smoothing of motor asymmetry but did not change its general pattern. Thus, our findings allow us to believe that a noticeable proportion of the goldfish individuals (similarly to other animals and humans) is characterized by an innate asymmetry of the motor function with a clear preference for either right- or left-side turnings. These relations can be smoothed under experimental influences but are recovered later on, i.e., they are stable and are not fundamentally transformed. We assume that the asymmetry of motor behavior of fishes in a narrow channel can be an adequate pre-requisite for further examination of the asymmetry of the brain and motor centers controlling changes in locomotion (body turnings)Neirofiziologiya/Neurophysiology, Vol. 37, No. 1, pp. 52–60, January–February, 2005.     

The characteristics of motor asymmetry in the ontogeny of calves]

The side of preference (first turn of head) was recorded in calves in situation of free equal probability two-sides choice, and rate of reconstruction of conditioned reflex to food presented from the left or from the right was determined. Initially the calves preferred the left turn, i.e. manifested motor asymmetry. Preference to the left turn changed depending on the calves age with the period of 22-23 days. The rate of conditioned reflexes reconstruction was higher in calves with the left-side preference. Correlation of the motor asymmetry and rate of conditioned reflex reconstruction in calves of different age changed in analogy with age changes of asymmetry. Probably the observed periodical changes of asymmetry and its correlation with the rate of reconstruction reflect formation of interhemispheric interactions in regulation of the organism functions in animals ontogenesis.     

Modulation of Behavioral Reactions of Rats with Different Profiles of Motor Asymmetry upon the Action of Hypokinetic Stress

Hypokinetic stress-induced modifications of behavioral reactions recorded under conditions of the open-field test were studied in rats. Animals with different profiles of motor asymmetry demonstrated significant individual typological specificity of behavior. Experimental 9-day-long restriction of mobility caused clearly pronounced changes in behavioral and emotional reactions in the animals; manifestations of such changes depended significantly on motor lateralization.     

Morphological parameters of mauthner neurons of goldfishes with modified asymmetry of motor behavior

We examined the morphological peculiarities of Mauthner neurons, MNs, in goldfishes with a phenotypically different or an experimentally modified preference to perform rightward vs leftward turnings in the course of motor behavior; this preference was characterized by values of the motor asymmetry coefficient (MAC). 3D reconstruction of MNs was performed based on several histological sections; volumes of the soma, lateral and ventral dendrites (LD and VD, respectively), initial segment of the axon, as well as full volumes of the right and left neurons, were calculated. Differences between the above parameters were expressed as structural asymmetry coefficients (SACs). It was shown that clear orientation asymmetry of motor behavior of the fish is accompanied by differences in the dimensions of MNs and their compartments; MNs localized contralaterally with respect to the preferred turning side were considerably bigger than ipsilateral neurons. Experimental influences inducing inversion of the motor asymmetry of fishes inverted structural asymmetry of their MNs. In fishes with no phenotypical preference of the turning side and in individuals whose motor asymmetry was smoothed due to experimental influences (rotational stimulations), structural asymmetry of the MNs was also smoothed. Changes of the structural proportions developed, as a rule, due to decreases in the dimensions of one or both MNs and their compartments. The MAC value was in direct correlation with the value of SAC of the MNs and with values of this coefficient for the soma and the sum soma + LD. At the same time, reciprocal relations were found for the MAC and structural asymmetry of the VD; the decrease in the volume of VD was related to an increase in the preference of the contralateral turning side by the fish, and vice versa. In general, the results of our study demonstrate that both morphological and functional peculiarities of MNs correlate to a significant extent with such a form of motor behavior of fishes as realization of spontaneous turnings. Neirofiziologiya/Neurophysiology, Vol. 38, No. 1, pp. 18–31, January–February, 2006.     

Finger ridge-count asymmetry and diversity in Andean Indians and interpopulation comparisons

A separate analysis of ulnar and radial finger ridge-counts, obtained from 115 Aymara Indians (55 males and 60 females) of northern Chile, was performed. From these variables, directional asymmetry, fluctuating asymmetry, indices of bilateral asymmetry (√A²), and intraindividual diversity (s/√5) were calculated for each sex. The results show that most bimanual differences for the ridge-counts are not statistically significant in the Aymara, except for radial counts in female first and second fingers (right hand means are larger), while most ulnar-radial differences are highly significant in both sexes (radial values exceed ulnar ones). Most sex differences do not reach statistical significance, although males have more ridge-counts, lower directional asymmetry, somewhat lower fluctuating asymmetry, and lower indices of asymmetry and diversity than females. As fluctuating asymmetry is not larger in males, the dermatoglyphic findings do not indicate support for the hypothesis that males are less canalized than females. In accordance with the findings of other authors, interpopulation comparisons in the indices of asymmetry and diversity show ethnic differences. Both indices tend to be low in samples of African ancestry, high in samples of European origin, and intermediate in the Aymara, while Indian groups are characterized by high asymmetry and low diversity values. Moreover, the data reveal a geographical trend in that asymmetry and diversity values tend to decrease from the northern to the southern hemisphere in populations of Europe, the Middle East, and Africa, thus indicating greater ridge-count variability and heterogeneity among fingers in northern populations. It is assumed that this gradient primarily reflects different degrees of miscegenation and heterozygosity. Am J Phys Anthropol 105:377–393, 1998. © 1998 Wiley-Liss, Inc.     

Rotational stimulation-related changes of the motor asymmetry in the goldfish

We studied changes in the motor asymmetry of the goldfish induced by single-session long-lasting vestibular stimulations (clockwise and counter clockwise rotations around the rostro-caudal body axis) and repetitive everyday short sessions of such stimulation (training); the latter mode led to the development of adaptation (resistance to fatigue). Rotational stimulation of different durations and directions elicited effects of different patterns and intensities. Such stimulation enhanced or, vice versa, smoothed the motor asymmetry in “dextral” and “ sinistral” fishes, up to full symmetry or even a change of the preferred turning direction. Adaptation to unilateral rotational stimulation allows an experimenter to selectively and gradually induce the resistivity of the left-or right-ward asymmetry to fatigue effects. Earlier, we found that the motor asymmetry in the goldfish, which is determined by the functional asymmetry of the brain, correlates with the morphological asymmetry of Mauthner neurons localized in the medulla in a mirror manner and playing a crucial role in the control of turnings in the course of locomotion (swimming). Experimental rotational stimulation-induced gradual modification of the motor asymmetry in the goldfish can serve as a physiological model for more detailed studies of the structural base of the functional brain asymmetry and some mechanisms of adaptation on the level of single neurons. Neirofiziologiya/Neurophysiology, Vol. 37, Nos. 5/6, pp. 432–442, September–December, 2005.     

Daily zinc supplementation effect on zinc deficiency in rats during prolonged restriction of motor activity

The objective of this investigation was to evaluate the effect of 47 mg zinc supplementation on deficiency of zinc in rats during 98 d of restriction of motor activity (hypokinesia), which appeared by higher plasma zinc concentration. One Hundred 13-week-old Sprague-Dawley male rats weighing 360–390 g were used to perform the studies: They were equally divided into four groups: 1. Unsupplemented control animals (UCA); 2. Unsupplemented hypokinetic animals (UHA); 3. Supplemented control animals (SCA); and 4. Supplemented hypokinetic animals (SHA). For the simulation of the effect of hypokinesia (HK), the UHA and SHA were kept in small individual cages made of wood, which restricted their movements in all directions without hindering food and water intake. The SCA and SHA received daily with their food an additional amount of zinc. Before and during the experimental period of 98 d, plasma, urinary and fecal zinc, balance of zinc, food intake, and body weight were determined at different intervals. In the SHA and UHA, the concentration of zinc in plasma, and the elimination of zinc in urine and feces increased significantly when compared with the SCA and UCA, whereas the balance of zinc was negative. The body weight and food intake decreased significantly in the SHA and UHA when compared with the SCA and UCA. The increased plasma concentration of zinc in both the SHA and UHA groups was in contrast to the observed hypozincnemia during prolonged immobilization as during prolonged hospitalization. This reaction suggests that there may be some other mechanisms that are affecting the process of control and regulation of zinc metabolism during prolonged HK. It was concluded that exposure to prolonged restriction of motor activity of rats induces significant increases in plasma concentration, fecal and urinary elimination of zinc in the presence of negative zinc balance and regardless the daily intake of large amounts of zinc with their food, leading to zinc deficiency.