Approach and Withdrawal Motivation in Schizophrenia: An Examination of Frontal Brain Asymmetric Activity

Although motivational disturbances are common in schizophrenia, their neurophysiological and psychological basis is poorly understood. This electroencephalography (EEG) study examined the well-established motivational direction model of asymmetric frontal brain activity in schizophrenia. According to this model, relative left frontal activity in the resting EEG reflects enhanced approach motivation tendencies, whereas relative right frontal activity reflects enhanced withdrawal motivation tendencies. Twenty-five schizophrenia outpatients and 25 healthy controls completed resting EEG assessments of frontal asymmetry in the alpha frequency band (8–12 Hz), as well as a self-report measure of behavioral activation and inhibition system (BIS/BAS) sensitivity. Patients showed an atypical pattern of differences from controls. On the EEG measure patients failed to show the left lateralized activity that was present in controls, suggesting diminished approach motivation. On the self-report measure, patients reported higher BIS sensitivity than controls, which is typically interpreted as heightened withdrawal motivation. EEG asymmetry scores did not significantly correlate with BIS/BAS scores or with clinical symptom ratings among patients. The overall pattern suggests a motivational disturbance in schizophrenia characterized by elements of both diminished approach and elevated withdrawal tendencies.     

Adenosine receptors are involved in the control of acute naloxone-precipitated withdrawal: in vitro evidence

The effects exerted by adenosine A1 and A2 receptor agonists and antagonists on the acute opiate withdrawal induced by morphine were investigated in vitro. Following a 4 min in vitro exposure to morphine, the guinea-pig isolated ileum exhibited a strong contracture after the addition of naloxone. The P1 adenosine receptor agonist, adenosine, was able to reduce dose-dependently naloxone-precipitaded withdrawal. The same effect was induced by the adenosine A1 receptor agonist, N6-Cyclopentyladenosine (CPA) whereas the selective adenosine A2A receptor agonist CGS 21680 increased the naloxone-precipitated withdrawal phenomenon. Dipyridamole, a blocker of adenosine reuptake, induced a significant reduction of morphine dependence. Caffeine, an adenosine receptor antagonist, significantly increased the naloxone-precipitated withdrawal effect in a concentration dependent manner. The same effect was observed with 8-phenyltheophylline (8PT), an A1 adenosine receptor antagonist, whereas 3,7-dimethyl-1-propargylxanthine (DMPX), an A2 adenosine receptor antagonist, reduced the naloxone-precipitated withdrawal phenomenon. The results of our experiments indicate that both A1 and A2 adenosine receptor agonists and antagonists are able to influence opiate withdrawal in vitro, suggesting an important functional interaction between the adenosine receptors and opioid withdrawal.     

Selected line difference in sensitivity to a GABAergic neurosteroid during ethanol withdrawal

The neurosteroid allopregnanolone (ALLO) is a potent positive modulator of gamma-aminobutyric acid(A) (GABA(A)) receptors. Earlier work indicates that sensitivity to the anticonvulsant effect of ALLO was enhanced during ethanol (EtOH) withdrawal in rats and in C57BL/6 mice, an inbred strain with mild EtOH withdrawal. In contrast, ALLO sensitivity was reduced during EtOH withdrawal in DBA/2 mice, an inbred strain with severe EtOH withdrawal. Thus, the present studies examined ALLO sensitivity during EtOH withdrawal in another animal model of EtOH withdrawal severity, the Withdrawal Seizure-Prone (WSP) and Withdrawal Seizure-Resistant (WSR) selected lines. Male mice were exposed to EtOH vapor or air for 72 h. During peak withdrawal, animals were injected with ALLO [0, 3.2, 5, 10 or 17 mg/kg, intraperitoneally (i.p.)] and tested for their sensitivity to the anticonvulsant effect. In separate studies, potentiation of GABA-stimulated chloride uptake by ALLO (10 nm to 10 microm) was assessed in microsacs prepared from mouse brain mice during peak withdrawal. Notably, WSP mice were cross-tolerant to the anticonvulsant effect of ALLO during EtOH withdrawal (i.e. significant decrease in the efficacy of ALLO) when compared with values in air-exposed mice. In contrast, sensitivity to the anticonvulsant effect of ALLO was unchanged during EtOH withdrawal in the WSR line. Functional sensitivity of GABA(A) receptors to ALLO was significantly decreased during EtOH withdrawal in WSP mice in a manner consistent with the change in behavioral sensitivity to ALLO. These findings suggest that mice selectively bred for differences in EtOH withdrawal severity are differentially sensitive to ALLO during EtOH withdrawal.     

Anti-IL-17A blocking antibody reduces cyclosporin A-induced relapse in experimental autoimmune encephalomyelitis mice

Cyclosporin A (CsA) is effective at reducing pathogenic immune responses, but upon withdrawal of CsA the immune response often “rebounds” resulting in a relapse or exacerbation of disease. The mechanisms, cells and cytokines involved in the relapse or exacerbation after CsA withdrawal are unknown. We hypothesized that CsA withdrawal induces IL-17 production that could be responsible for relapse, and examined the effect of anti-IL-17A antibody on relapse induced after CsA withdrawal in mouse experimental autoimmune encephalomyelitis (EAE). CsA treatment markedly decreased the EAE disease score during the first episode, but augmented disease severity after CsA withdrawal, compared to untreated mice. After discontinuation of CsA the production of IL-17A was increased and the severity of relapse in EAE was reduced by treatment with anti-IL-17A antibody. These results suggest that the resumption of T cell immune responses after CsA withdrawal leads to a burst of IL-17A production that is at least partially responsible for relapse in EAE mice.     

ANALYSIS OF GENOTYPIC DIFFERENCES IN DEVELOPMENTAL STABILITY IN ANNONA CHERIMOLA

The genetic basis of developmental stability, measured as asymmetry (fluctuating asymmetry in leaves), was analyzed in leaves and flowers of cherimoya (Annona cherimola Mill) and atemoya (A. cherimola × A. squamosa). The individuals analyzed belonged to a controlled collection of cultivars (clones) that had previously been characterized by means of isozymes. We used a nested design to analyze the differences in asymmetry at several sampling levels: individual leaves and flowers, individual trees, and genotypes. The clonal repeatability of developmental stability was not significantly different from zero, thus suggesting the absence of heritability of the asymmetry for leaves and flowers under these environmental conditions. No relationship between asymmetry and individual heterozygosity was found, but leaf fluctuating asymmetry was significantly related to particular isozymic genes. Petal and leaf size showed a phenotypically plastic response to the exposure zone of the tree (mainly due to light). Leaf fluctuating asymmetry also showed such a plastic response. No significant correlation was found between asymmetry and any pomological characters (some of these being fitness related). Finally, the hybrid species (atemoya) did not show larger developmental instability than did the parental species (cherimoya). All these data show that cherimoya asymmetry reveals the random nature of developmental noise, with developmental stability for leaves being possibly related to specific chromosome regions, but with weak evidence for genotypic differences in developmental stability.     

Psychophysiology of sports addiction (exercises addiction)

Addiction is a prevalent and growing concern in all aspects of our modern society. There are considerable concerns for the growing frequency of addictions to drugs, alcohol, gambling, eating, and even sex. Though exercise is generally accepted as a positive behaviour that has many benefits associated with enhanced physical and psychological wellbeing, there is an increasing awareness that exercise addiction is becoming a common phenomenon. Theories regarding how exercise can become addictive, and studies of withdrawal from exercise are reviewed. Several physiological mechanisms, including endogenous opioids, catecholamines, functional asymmetry of brain activity and thermoregulation have been implicated in exercise dependence.     

Bilateral asymmetry of the humerus during growth and development

The development of handedness throughout growth can be investigated by using bilateral asymmetry of the humerus as a proxy for this trait. A large skeletal sample of nonadults from English archaeological sites was examined using standard metric techniques to assess when right-sided asymmetry first appears in the human skeleton. Results of this work indicate a change in directional asymmetry during growth and development, with infants and young children exhibiting no significant asymmetry and older children and adolescents demonstrating right-sidedness. This trend is consistent with what has been observed in previous studies of upper limb asymmetry in skeletal material and behaviorally in living children, adding further strength to the premise that biomechanical forces strongly influence bilateral asymmetry in the upper limb bones. Variability in the magnitude of asymmetry between different features of the humerus was also noted. This characteristic can be explained by differing degrees of genetic canalization, with length and articular dimensions being more strongly canalized than diaphyseal properties.     

Quantitative Assessment of the Effects of Hemispheric Asymmetry on the Distortion of Visual Perception of the Jastrow Version of the Poggendorff Figure

A method for quantifying the visual distortion of the Poggendorff figure (Jastrow modification) was proposed. Complex relationships of the relative distortion with the gender and the type of hemispheric asymmetry were determined. Females had a more pronounced tendency to be under the illusion than males. However, when the total sample was divided with respect to the pattern of hemispheric asymmetry, this difference was found only in subjects with left-hemispheric dominance in the visuomotor asymmetry, i.e., in right-handers. No difference was found between males and females with right-hemispheric dominance.     

Cerebral Metabolic State During the Ethanol Withdrawal Reaction in the Rat

Abstract: A severe ethanol withdrawal reaction was induced in rats by means of repeated intragastric intubation during a 4-day period. At the peak of the withdrawal reaction cerebral cortical tissue was frozen in situ for analysis of glycogen, glucose, phosphocreatine, creatine, ATP, ADP, AMP, lactate, pyruvate, GAB A, β-hydroxybutyrate, acetoacetate, cAMP and cGMP. Blood glucose concentration was also measured. The level of brain glycogen was decreased during ethanol withdrawal. Brain glucose concentration was increased, probably secondary to the increase in blood glucose concentration. The calculated NADH/NAD⁺ ratio was slightly increased during the withdrawal and brain ATP concentration and adenine nucleotide pool size were decreased. The adenylate energy charge remained unchanged. The overall changes in the metabolites were in agreement with the previously shown metabolic activation during ethanol withdrawal. The brain concentrations of ketone bodies (β-hydroxybutyrate and acetoacetate) during withdrawal did not deviate from controls, indicating that no abnormal ketone metabolism had developed as a consequence of the long-lasting ethanol intoxication. No changes were observed in the concentrations of GABA, cAMP, or cGMP in the rat cerebral cortex during ethanol withdrawal.     

Genetic and phenotypic correlation between fluctuating asymmetry and two measurements of fear and stress in chickens

The purpose of the present study was to estimate the genetic and phenotypic correlation between fluctuating asymmetry and two measurements of fear and stress in chickens which had not deliberately stressed in any way, using the restricted maximum likelihood procedure. A total of 1073 36-week-old birds from two generations with complete pedigree of the Quail Castellana breed was used. Fluctuating asymmetry of several traits (leg, wing, and feather lengths, and ear-lobe and wattle areas), tonic immobility duration (indicator of fear), and heterophil to lymphocyte ratio (indicator of stress) were measured. The estimated genetic relationship between relative fluctuating asymmetry for the different traits and tonic immobility tended to be positive, that between the combined relative asymmetry of all traits and tonic immobility being near to +1; no significant phenotypic relationship was found between relative fluctuating asymmetry and tonic immobility. The genetic relationship between relative fluctuating asymmetry and heterophil to lymphocyte ratio was not consistent across the traits, ranging from +1 to −1, although the genetic correlation between the combined relative asymmetry and the heterophil to lymphocyte ratio was near to +1 too; no significant phenotypic relationship was found between relative fluctuating asymmetry and heterophil to lymphocyte ratio either. Relative fluctuating asymmetry and body weight were genetically negatively correlated for leg length and ear-lobe area but positively for feather length; the genetic correlation between the combined relative asymmetry and the body weight being near to −1; phenotypic relationships were not significantly different from zero. A significant negative genetic correlation between tonic immobility and heterophil to lymphocyte ratio was found, although the phenotypic association between these two measurements was zero. Phenotypic correlations always near to zero suggest that fluctuating asymmetry was not associated with duration of tonic immobility and heterophil to lymphocyte ratio in birds that have not been deliberately stressed.     

蜘蛛抱蛋属植物的核型不对称性分析

报道了蜘蛛抱蛋属(Aspidistra)两种植物的染色体数目和核型,其中河口蜘蛛抱蛋(A.hekouensi)的染色体数目(2n=38)为首次报道,四川蜘蛛抱蛋(A.sichuanensis)染色体数目也为2n=38,但其核型与以往的报道有差别.使用染色体内不对称系数(A1)和染色体间不对称系数(A2)对该属34种植物核型的不对称性进行了分析,结果表明该属植物的核型似乎并没有向不对称性增强的方向演化.     

The allometry of fluctuating asymmetry in southern African plants: flowers and leaves

Several studies of fluctuating asymmetry (FA) in animals show that secondary sexual characters used in signalling have a negative relationship between size and asymmetry. Larger sexual traits are presumably more costly to produce, which should lead to greater developmental stress and corresponding increases in asymmetry. In the absence of among individual variation in the ability to handle these costs, the relationship between size and asymmetry should thus be positive. A negative relationship therefore suggests that expression of these traits is condition-dependent. In plants, flowers act as signals for pollinators and may show similar trends to animal signals. Leaves which are uninvolved in signalling should not. Moller & Eriksson (1994) found that 89% of species ( n = 16 of 18) with insect-pollinated flowers showed a negative relationship between petal size and asymmetry, while 79% of species ( n = 15 of 19) showed a positive relationship between leaf size and asymmetry. I carried out a similar study of 18 plant species. The average relationship between petal size and asymmetry did not differ significantly from zero in those species showing measurable FA in flowers ( n = 12). The relationship was significantly negative in one species, and significandy positive in another. On average, leaves in species with FA did not show a significant positive relationship between size and asymmetry ( n = 7). There was no significant difference in the slopes of the relationship between size and asymmetry for leaves and flowers. Levels of floral asymmetry for species with FA were significandy repeatable on individual plants in 33% ( n = 4 of 12) of species, but leaf asymmetry was not significantly repeatable in any species. It is argued that condition-dependence of traits need not result in a negative relationship between size and asymmetry.     

Morphine withdrawal inhibits IL-12 induction in a macrophage cell line through a mechanism that involves cAMP

There are very few studies that examine the effects that morphine withdrawal has on immune functioning, and of these even fewer describe the mechanisms by which withdrawal brings about these changes. Our previous work demonstrated that morphine withdrawal contributed to Th cell differentiation by biasing cells toward the Th2 lineage. A major finding from these studies was that IL-12 was decreased following withdrawal, and it was concluded that this decrease may be a mechanism by which morphine withdrawal is mediating Th2 polarization. Therefore, it was the aim of the current studies to develop an in vitro model to examine the process of morphine withdrawal and to understand the signaling mechanisms that withdrawal may use to effect IL-12 production through the use of this model. It was demonstrated and concluded that morphine withdrawal may be effecting IL-12 production by increasing cAMP levels, which activates protein kinase A. Protein kinase A activation then prevents the phosphorylation and subsequent degradation of IkappaB, which in turn prevents translocation of the NF-kappaB p65 subunit to the nucleus to transactivate the IL-12 p40 gene, ultimately resulting in decreased IL-12 production following LPS stimulation.     

Inbreeding reduces power-law scaling in the distribution of fluctuating asymmetry: an explanation of the basis of developmental instability

The study of fluctuating asymmetry has been controversial because of conflicting results found in much of the primary literature. It has been suggested that the source of this conflict is the fact that the basis of fluctuating asymmetry is poorly understood and that, as a consequence, methodology of fluctuating asymmetry studies may be flawed. A new model for the phenomenological basis of fluctuating asymmetry, that variation in fluctuating asymmetry is in large part due to the random exponential growth of cell populations (geometric Brownian motion) that are terminated randomly around a genetically programmed development time, is presented here. If termination of development has a genetic component, then scaling effects and kurtosis in the distribution of fluctuating asymmetry should increase with genetic redundancy of the population. This model prediction was tested by comparing the distribution of multivariate size and shape fluctuating asymmetry in large samples collected from both wild populations and four moderately inbred lines of Drosophila simulans. It was found that while wild populations were best described by a lognormal distribution with power-law scaled tails, the inbred lines derived from the wild stock were dramatically normalized (half-normal) in three of four cases. As predicted, the scaling exponent of the upper tail of the distribution of fluctuating asymmetry increased with inbreeding while the kurtosis and mean fluctuating asymmetry decreased with inbreeding. The model suggests an additional explanation of leptokurtosis in fluctuating asymmetry. Kurtosis and scaling of the statistical distribution of fluctuating asymmetry in a population is related directly to genetic differences between individuals and these differences affect their ability to buffer the process of development against random perturbations.     

Computer experiment for selection of optical isomer during prebiotic polymerization

Computer experiments simulating prebiotic polymerization were carried out using the Monte Carlo method. A high degree of selection of single optical isomers from racemic monomers occurred by assuming a small asymmetry in their chemical natures, which was included to investigate an, amplification of the asymmetry due to parity non-conservation. The asymmetry developed much more slowly than the growth of polymers, and the degree of asymmetry in the polymers increased with the degree of polymerization. Competition between the preferential selection and the disturbance by the statistical fluctuation are discussed.     

Fluctuating asymmetry in the honey bee,Apis mellifera: effects of ploidy and hybridization

We present a new measure of morphological asymmetry that avoids most of the statistical problems inherent in character-by-character analysis of size or shape. The method is an application of Procrustes analysis, which computes best-fitting super-positions of configurations of landmarks to the left and right sides of a single specimen. The Procrustes method combines subtle deviations in all aspects of the landmark configuration into one net asymmetry score. Directional asymmetry is separated from fluctuating asymmetry in a simple partition of a net sum-of-squares, and geometrical details of either component can be inspected by traditional methods of multivariate statistical analysis of landmarks. We demonstrate this method in a comparison of wing venation asymmetry in male (haploid) and female (diploid) honey bees (Apis mellifera). In addition we investigate the effects of ploidy and inter-subspecies hybridization on asymmetry and wing venation abnormalities, using the subspecies A. m. mellifera, A. m. carnica, and the hybrid strain “Nigra”. Results suggest that while the haploid males showed a higher frequency of wing venation abnormalities and greater total asymmetry than the diploid females, most of the asymmetry difference between males and females was in the form of directional, not fluctuating, asymmetry. Hybrid females had a higher frequency of wing venation abnormalities than females of either subspecies, but there were no significant differences in the mean level of asymmetry among females of A. m. mellifera, A. m. carnica and hybrid Nigra. Hybrid males had higher absolute frequency of wing venation abnormalities and asymmetry than males of either subspecies. However the mean frequency of venation abnormalities did not differ significantly between Nigra and A. m. carnica males, and mean asymmetries were not significantly different between Nigra and A. m. mellifera males. We discuss the relationship which is assumed to exist between developmental stability and fluctuating asymmetry in light of our result.     

Behavioral and morphological asymmetries in roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (Cyprinidae: Cypriniformes) underyearlings

The underyearlings of roach, Rutilus rutilus, displayed a bilateral asymmetry of C-bend—the initial stage of escape behavior. Most individuals exhibited a significant bias to turn leftward or rightward after being stimulated by electrical current. This individual asymmetry was consistent when the same fish were retested ten days later. A significant correlation was revealed between the behavioral asymmetry and the bilateral asymmetry of surface area of frontal (positive correlation) and parietal (negative correlation) cranial bones. No significant correlation was found with the bilateral asymmetry of other morphological characteristics: numbers of pores of the seismosensory canals (praeopercular-mandibular, supraorbital, and supratemporal) in flat cranial bones (dental, praeopercular, frontal, and parietal numbers of lateral line pores, and numbers of rays in pectoral and ventral fins.     

Dynamics of the activities of postural asymmetry factors and of the recovery of motor function in damage to the neocortex of the left and right hemispheres

The role of postural asymmetry factors in the recovery of motor function after unilateral cortical lesions was investigated. The differences in the time-course of motor reactions recovery after left- and right-sided cortical damage was found. A more effective compensation of motor defects in animals with left-sided damage was accompanied by stable activity of postural asymmetry factors. The reported results indicate an important role of postural asymmetry factors in the early compensatory intra-central rearrangements.     

Self-polarization and directional motility of cytoplasm

Background: Directional cell motility implies the presence of a steering mechanism and a functional asymmetry between the front and rear of the cell. How this functional asymmetry arises and is maintained during cell locomotion is, however, unclear. Lamellar fragments of fish epidermal keratocytes, which lack nuclei, microtubules and most organelles, present a simplified, perhaps minimal, system for analyzing this problem because they consist of little other than the motile machinery enclosed by a membrane and yet can move with remarkable speed and persistence.Results: We have produced two types of cellular fragments: discoid stationary fragments and polarized fragments undergoing locomotion. The organization and dynamics of the actin–myosin II system were isotropic in stationary fragments and anisotropic in the moving fragments. To investigate whether the creation of asymmetry could result in locomotion, a transient mechanical stimulus was applied to stationary fragments. The stimulus induced localized contraction and the formation of an actin–myosin II bundle at one edge of the fragment. Remarkably, stimulated fragments started to undergo locomotion and the locomotion and associated anisotropic organization of the actin–myosin II system were sustained after withdrawal of the stimulus.Conclusions: We propose a model in which lamellar cytoplasm is considered a dynamically bistable system capable of existing in a non-polarized or polarized state and interconvertible by mechanical stimulus. The model explains how the anisotropic organization of the lamellum is maintained in the process of locomotion. Polarized locomotion is sustained through a positive-feedback loop intrinsic to the actin–myosin II machinery: anisotropic organization of the machinery drives translocation, which then reinforces the asymmetry of the machinery, favoring further translocation.     

Modification of developmental instability and fitness: Malathion-resistance in the Australian sheep blowfly,Lucilia cuprina

The evolution of resistance to malathion byLucilia cuprina initially results in an increase in fluctuating asymmetry. Resistant flies are at a selective disadvantage, relative to susceptibles, in the absence of the insecticide. A fitness/asymmetry modifier of diazinon-resistant phenotypes ameliorates these effects resulting in malathion-resistant phenotypes of relative fitness and asymmetry similar to susceptibles. For the nine genotypic combinations of the modifier and malathion-resistance alleles, developmental time increases linearly with increasing asymmetry. Percentage egg hatch decreases linearly with increasing asymmetry. The initially disruptive effect of the malathion-resistant allele was partially dominant, the effect of the modifier dominant. The results are discussed in terms of developmental perturbation, asymmetry estimation and relative fitness to consider whether it is adequate to use changes in fluctuating asymmetry alone as measures of developmental instability. It is suggested that in some circumstances antisymmetry may indicate developmental instability and that the diazinon/malathion-resistance systems inL. cuprina may allow the relative importance of genetical and/or environmental developmental perturbations to be ascertained.