下肢长骨骨重的非对称性

本文测量82副中国成年下股长骨即股骨,胫骨和腓骨的重量,在两侧骨重相差>1％时,则股骨、胫骨和腓骨及其三骨总重均以非对称性为多,均具有非常显著性差异(P<0.001)。除腓骨重具有明显侧别差异外,其余无显著性侧别差异,对腓骨侧差解释为:①腓骨主要机能是肌的附着,而下肢对踢和足趾取物具有明显的侧别差异;②以两侧骨重相差>1％时为非对称性的标准,由于腓骨绝对重量较小,在两侧相差<0.5克时即多属非对称性。     

The activity of postural asymmetry factors in symmetrical sections of the rat spinal cord

The distribution of the low-molecular weight and high-molecular weight postural asymmetry factors (FPA) activity in the left and right parts of the lumbal region of the rat spinal cord was studied. Low-molecular weight FPA induces flexion of the hind limb ipsilateral to the half of the spinal cord from which FPA was isolated, while high-molecular weight FPA induces contralateral flexion. The activities of the low- and high-molecular weight FPAs in each half of the spinal cord are comparable in normal rat. After the suction lesion of the motor areas in the left hemisphere the increase of the low-molecular weight FPA activity in the right half of the lumbal region of the spinal cord was observed.     

Hemispheric participation in the shaping of spatial-motor asymmetry in visual recognition in rats

Asymmetry of movement direction was found in Wistar rats at establishing of motor alimentary conditioned reflex to simultaneously presented visual stimuli. In the course of learning the asymmetry weakened on the whole, but some individuals retained right- or left side preference. The analysis of asymmetry change before and after unilateral cortical inactivation revealed a special role of right hemisphere influences for the formation of right-side preference and of the left hemisphere--for the choice of the left direction. The lack of asymmetry was observed at the presence of the influences from the left hemisphere cortex depressing ipsilateral nigro-striate system and activating the contralateral one. Influences of the cortex of both hemispheres reduce the absolute value of the asymmetry coefficient; the left hemisphere has a special significance for manifestation of temporal asymmetry parameters. Photic interference is a factor modulating the asymmetry. It reduces the right hemisphere activity more than that of the left one; it intensifies right hemisphere influences, contributes to the involvement of the transcallosal conduction channel in the formation of spatial-motor asymmetry.     

Asymmetry and sexual dimorphism of lungs weight in fetal ontogeny.

1079 male fetuses and 727 female fetuses at the age of 20 to 41 weeks were investigated for the process of asymmetry and sexual dimorphism of lungs weight formation as well as developmental correlation between the weight of the lungs and the size of the heart. Statistical analysis of the results was applied. It was ascertained, among others, that asymmetry of lungs weight occurs in the investigated developmental period--the right lung is heavier than the left one about 20 to 30%. Between the increase in the weight of the lungs and the size of the heart positive correlation occurs, but it is not of directed character. A substantial, intersexual differentiation of lungs weight was not ascertained.     

No Evidence for the Compensation Hypothesis in the Swelled Vent Frog(Feirana quadranus)

The compensation hypothesis predicts that if the left testis is defective e.g. due to developmental stress,the increased right testis serves a compensatory role, and thereby displaying testes asymmetry which can be a reliable indicator of male body condition. Here, to test the prediction of the compensation hypothesis, we analyzed difference in size between left testis and right testis and the relationship between testes asymmetry and male body condition in the swelled vent frog(Feirana quadranus).We found that the left testis was larger than right testis,displaying a significant directional asymmetry in testes size. Although testes mass was correlated with body condition, testes asymmetry was not correlated with body condition, which cannot provide evidence that the right testis had a compensatory function. Our findings suggest no evidence for the compensation hypothesis in this species due to lacking the compensatory function in right testis.     

Interhemispheric asymmetry of positive emotional reactions in rats

Interhemispheric asymmetry of positive emotional reactions was studied in rats: satisfaction of drinking need and self-stimulation. Successive inactivation of the hemispheres was carried out by potassium spreading depression. Switching off of the right as well as the left hemispheres symmetrically influenced the whole quantity of the water, drunk by the rats to a full thirst satisfaction, i. e. the magnitude of need. However, at different stages of drinking need satisfaction an interhemispheric asymmetry was observed: under a strong drinking motivation the right hemisphere dominated, under a weak motivation--the left one. Switching off of the right hemisphere lowered the frequency of self-stimulation of the lateral hypothalamus and switching off the left one heightened it, testifying to the dominance of the right hemisphere in the reaction of self-stimulation. This reaction was also characterized by asymmetry of the lateral hypothalamus nuclei; reactivity to hemispheres inactivation (decreasing or increasing of self-stimulation frequency) of the right nucleus was more expressed than that of the left one.     

Directional asymmetry in the forelimb of Macaca mulatta

Asymmetry was investigated in the forelimbs of 150 rhesus monkey (Macaca mulatta) skeletons using measurements of right and left humerii, radii, ulnae, second metacarpals, and femora. Seven of the ten forelimb dimensions were larger on the right than on the left side. Paired t-tests revealed that the mean of the right side was significantly larger than that for the left for two measurements of the ulna and two of the humerus. No measurement was significantly larger on the left than on the right side. These results indicate a small but significant asymmetry in the forelimb bones of rhesus monkeys and, as is the case for humans, the direction of asymmetry favors the right side. Our findings are consistent with an interpretation of hypertrophy of certain muscles and opens the question of whether rhesus monkeys preferentially use their right forelimbs for manipulative tasks that require manual dexterity, as is the case for humans. These forelimb skeletal asymmetries are discussed in light of the recent literature on cortical asymmetry and handedness in nonhuman primates.     

Morphological asymmetry and behavioral laterality in the crayfish, Procambarus clarkii

Lateral asymmetry is found widely among vertebrates, but is scarcely observed in invertebrates. Here, morphological asymmetry and behavioral laterality of a wild crayfish, Procambarus clarkii, was investigated. The carapace morphology of crayfish showed left–right differences; in some, the right side of the carapace was larger than the left side, while in others, the left side was larger. A bimodal distribution in the direction of escape behaviors induced by a tactile stimulus was also observed. Experimental crayfish were definitively divided into two groups: individuals that frequently jumped leftward (right type) and those that jumped rightward (left type). Moreover, carapace asymmetry and lateralized escape responses were significantly correlated. These results suggest that crayfish exhibit left–right dimorphism in natural populations. The ecological advantages and maintenance mechanisms underlying these behaviors are also discussed.     

Norepinephrine Is Lateralized Within the Olfactory Bulbs of Male Mice

Abstract: Concentrations and in vitro release of norepinephrine were determined from left and right olfactory bulbs of adult male CD-1 mice. Norepinephrine concentrations from the left olfactory bulbs were significantly greater than those of the right ( p < 0.01). No statistically significant differences were obtained for dopamine, nor were there differences in tissue weights between the left and right olfactory bulb tissue samples. To verify further this asymmetry, release rates of norepinephrine were measured from superfused left and right olfactory bulbs. Norepinephrine output from the left olfactory bulb was significantly greater than that from the right ( p < 0.05). These results show that norepinephrine is lateralized within the olfactory bulbs of male mice. This asymmetry shows a clear catecholamine specificity with regard to concentrations and may be related to the lateralized olfactory processing that has been reported to occur in humans.     

The asymmetry of movement direction in freshwater shrimp (Gammarus oceanicus) in the open-field test

Behaviour of Gammarus oceanicus was studied in the open field test. For the whole except (n = 204) spatial-motor asymmetry was found. It was manifested in significantly greater number of movements clockwise (to the right) than counterclockwise (to the left). Animals with significant asymmetry dominated, forming 93.5% of the except. The asymmetry was characterized by distinct right-sided direction. Motor activity and spatial-motor asymmetry at repeated tests in the main weakened; the changes in "right" and "left" animals were manifested differently. The essential factor which disturbed the behaviour of the animals in the open field test (including the asymmetry of movement direction) proved to be a toxicant (oil pollution) action.     

Left‐right asymmetry in gut development: what happens next?

The gastrointestinal tract is an asymmetrically patterned organ system. The signals which initiate left‐right asymmetry in the developing embryo have been extensively studied, but the downstream steps required to confer asymmetric morphogenesis on the gut organ primordia are less well understood. In this paper we outline key findings on the tissue mechanics underlying gut asymmetry, across a range of species, and use these to synthesise a conserved model for asymmetric gut morphogenesis. We also discuss the importance of correct establishment of left‐right asymmetry for gut development and the consequences of perturbations in this process.     

Otx-dependent expression of proneural bHLH genes establishes a neuronal bilateral asymmetry in C. elegans

Bilateral asymmetry in Caenorhabditis elegans arises in part from cell lineages that differ on the left and right sides of the animal. The unpaired MI neuron descends from the right side of an otherwise left-right symmetric cell lineage that generates the MI neuron on the right and the e3D epithelial cell on the left. We isolated mutations in three genes that caused left-right symmetry in this normally asymmetric cell lineage by transforming MI into an e3D-like cell. These genes encode the proneural bHLH proteins NGN-1 and HLH-2 and the Otx homeodomain protein CEH-36. We identified the precise precursor cells in which ceh-36 and ngn-1 act, and showed that CEH-36 protein is asymmetrically expressed and is present in an MI progenitor cell on the right but not in its bilateral counterpart. This asymmetric CEH-36 expression promotes asymmetric ngn-1 and hlh-2 expression, which in turn induces asymmetric MI neurogenesis. Our results indicate that this left-right asymmetry is specified within the two sister cells that first separate the left and right branches of the cell lineage. We conclude that the components of an evolutionarily conserved Otx/bHLH pathway act sequentially through multiple rounds of cell division on the right to relay an initial apparently cryptic asymmetry to the presumptive post-mitotic MI neuron, thereby creating an anatomical bilateral asymmetry in the C. elegans nervous system.     

Interhemisphere differences of extrastriate cortical activation during attention and selection of lateralized visual stimuli in humans

The cortical activation was estimated by event-related potentials (ERPs) methods during selection tasks of lateralized visual stimuli in right and left hemi-fields requiring different forms of attention: 1. Attention of a stimuli form, 2. Attention of a stimuli position, 3. Combined attention of form and position. ERPs were recorded in 15 young healthy adults in 6 leads: P3, P4, T3, T4, T5, T6 and endogenous ERPs components: CNV (contingent negative variation), N1, P3 and complex [N1--P3]. The differences between ERPs at contra- and ipsilateral stimuli in the right and left hemispheres were considered as indices of asymmetry. The asymmetry was revealed in right hemisphere in all kinds of attention forms. The level (amplitude) of right-side asymmetry was depended on the level of attention: The significant relation between the right-side asymmetry and subjects' reaction time was also revealed. It is proposed that such an asymmetry is the evidence of better spatial differentiation of visual stimuli in right hemisphere in humans.     

Directional asymmetry of the zebrafish epithalamus guides dorsoventral innervation of the midbrain target

The zebrafish epithalamus, consisting of the pineal complex and flanking dorsal habenular nuclei, provides a valuable model for exploring how left-right differences could arise in the vertebrate brain. The parapineal lies to the left of the pineal and the left habenula is larger, has expanded dense neuropil, and distinct patterns of gene expression from the right habenula. Under the influence of Nodal signaling, positioning of the parapineal sets the direction of habenular asymmetry and thereby determines the left-right origin of habenular projections onto the midbrain target, the interpeduncular nucleus (IPN). In zebrafish with parapineal reversal, neurons from the left habenula project to a more limited ventral IPN region where right habenular axons would normally project. Conversely, efferents from the right habenula adopt a more extensive dorsoventral IPN projection pattern typical of left habenular neurons. Three members of the leftover-related KCTD (potassium channel tetramerization domain containing) gene family are expressed differently by the left and right habenula, in patterns that define asymmetric subnuclei. Molecular asymmetry extends to protein levels in habenular efferents, providing additional evidence that left and right axons terminate within different dorsoventral regions of the midbrain target. Laser-mediated ablation of the parapineal disrupts habenular asymmetry and consequently alters the dorsoventral distribution of innervating axons. The results demonstrate that laterality of the dorsal forebrain influences the formation of midbrain connections and their molecular properties.     

Behavioral and morphological asymmetries in chukar Alectoris chukar copulation

Birds often exhibit greater reproductive tract development on the left side than right side. Behavioral evidence from the three species for which data has been published indicates that these species copulate more frequently on the left side of females than on the right side. Missing from the literature are studies that compare asymmetry in copulation behavior to asymmetry in reproductive tract morphology of the same individuals of both sexes within a single species. To better understand the potential for cryptic sexual selection to influence avian copulation, we measured asymmetries in chukar Alectoris chukar copulation using 24 male and 29 female chukar brought into captivity from the wild. Chukar copulated (n=37) more from the left side (n=30) of females than the right side (n=7). The left testis of males was consistently greater in size, mass and volume than the right testis. The left ovary and oviduct of females was consistently functional with no observable development of the right ovary or oviduct. Left-side bias in direction of copulation, larger left testes, and functional left vaginal openings may act in concert to deliver spermatozoa to the oviduct, promoting fertilization.     

Antennal Asymmetry in Social Behavior of the Australian Stingless Bee, <Emphasis Type="Italic">Tetragonula carbonaria</Emphasis>

The left and right antennae of stingless bees have different roles in learning and recall of olfactory memory. Antennal asymmetry in social behavior is reported here. Approaches and physical contacts were scored in dyads of stingless bees (Tetragonula carbonaria): dyads in which both bees had only their right antennae (left antennae removed) made significantly more physical contacts with each other than dyads in which both bees had only their left antennae. In dyads of one left and one right, it was found, unexpectedly, that the bee with a left antenna approached the bee with the right antenna more often that the other way around, and the bee with the left antenna often attacked (by biting) its hive mate. Hence, the low number of contacts in dyads of bees using their left antennae appears to be due to mutual avoidance. Whereas use of the right antenna stimulates positive contact, the left stimulates avoidance or attack. Via such left-right asymmetries, intact bees may compute behavior directed towards friend and foe. Such antennal asymmetry may have evolved concomitantly with eusocial behavior. We found no evidence that it was associated with significant differences in the number of olfactory or non-olfactory sensilla on the left versus right antenna.     

The Predictive Nature of Pseudoneglect for Visual Neglect: Evidence from Parietal Theta Burst Stimulation

Following parietal damage most patients with visual neglect bisect horizontal lines significantly away from the true centre. Neurologically intact individuals also misbisect lines; a phenomenon referred to as ‘pseudoneglect’. In this study we examined the relationship between neglect and pseudoneglect by testing how patterns of pre-existing visuospatial asymmetry predict asymmetry caused by parietal interference. Twenty-four participants completed line bisection and Landmark tasks before receiving continuous theta burst stimulation to the left or right angular gyrus. Results showed that a pre-existing pattern of left pseudoneglect (i.e. right bias), but not right pseudoneglect, predicts left neglect-like behaviour during line bisection following right parietal cTBS. This correlation is consistent with the view that neglect and pseudoneglect arise via a common or linked neural mechanism.     

How birds use their eyes: Opposite left-right specialization for the lateral and frontal visual hemifield in the domestic chick

Recent evidence has demonstrated that, in animals with laterally placed eyes, functional cerebral asymmetry is revealed by preferential use of either the left or right eye in a range of behaviors (birds: [1, 2, 3]; fish: [4, 5]; reptiles: [6, 7]). These findings pose a theoretical problem. It seems that there would be disadvantages in having a substantial degree of asymmetry in the use of the two eyes; a deficit on one side would leave the organism vulnerable to attack on that side or unable to exploit resources appearing on one side. We here report a possible solution to the problem. We have found that domestic chicks show selective use of the lateral visual field of the left eye and of the right hemifield in the binocular, frontal visual field when they peck at strangers but not at cagemates. Thus, during social recognition, there seems to be opposite and complementary left-right specialization for the lateral and frontal visual fields of the two eyes. These findings can reconcile the computational advantages associated with asymmetry of the left and right sides of the brain with the ecological demands for an animal to perceive and respond equally well to the left and right sides of its midline.     

Hemispheric asymmetry of visual evoked potentials during human recognition of facial emotional expressions

Visual evoked potentials (VEP) in standard 16 EEG derivations were recorded in 26 young men and 20 women during recognition of facial emotional expressions and geometric figures. The stimuli were presented on a computer screen in the center of the visual field or randomly in the right or left vision hemifields. Peak VEP latency and mean amplitude in 50-ms epochs were measured; spatiotemporal VEP dynamics was analyzed in a series of topographic maps. The right hemisphere was shown to be more important in processing emotional faces. The character of the asymmetry was dynamic: at earlier stages of emotion processing the electrical activity was higher in the right inferior temporal region compared to the left symmetrical site. Later on the activity was higher in the right frontal and central areas. The dynamic mapping of "face-selective" component N180 of VEPs revealed the onset of activation over the right frontal areas that was followed by the fast activation of symmetrical left zones. Notably, this dynamics didn't correlate with the hemifield of stimuli exposition. The degree of asymmetry was lower during presentation of figures, especially in the inferior temporal and frontal regions. The prominent asymmetry of information processes in the inferior temporal and frontal areas was suggested to be specific for recognition of facial expression.     

Physical criteria of pathological processes. I. Change in the functional hemispheric asymmetry at various stages of rheumatic diseases]

The functional interhemispheric asymmetry of brain in patients with systemic rheumatic diseases was estimated by measuring brain direct current potentials. It is shown that different types of functional interhemispheric asymmetry correspond to different stages of systemic rheumatic diseases. At early stages, the left hemisphere asymmetry dominates, at expressed stages, the right hemisphere asymmetry is prevalent, and the terminal stage is characterized by the loss of functional interhemispheric asymmetry.