Individual Differences In Expression Research Articles

Decoding individual differences in expressing and suppressing anger from structural brain networks: A supervised machine learning approach

Anger can be broken down into different elements: a transitory state (state anger), a stable personality feature (trait anger), a tendency to express it (anger-out), or to suppress it (anger-in), and the ability to regulate it (anger control). These elements are characterized by individual differences that vary across a continuum. Among them, the abilities to express and suppress anger are of particular relevance as they determine outcomes and enable successful anger management in daily situations. The aim of this study was to demonstrate that anger suppression and expression can be decoded by patterns of grey matter of specific well-known brain networks. To this aim, a supervised machine learning technique, known as Kernel Ridge Regression, was used to predict anger expression and suppression scores of 212 healthy subjects from the grey matter concentration. Results show that individual differences in anger suppression were predicted by two grey matter patterns associated with the Default-Mode Network and the Salience Network. Additionally, individual differences in anger expression were predicted by a circuit mainly involving subcortical and fronto-temporal regions when considering whole brain grey matter features. These results expand previous findings regarding the neural bases of anger by showing that individual differences in specific anger-related components can be predicted by the grey matter features of specific networks.

Expression Analysis of Susceptibility Genes for Ossification of the Posterior Longitudinal Ligament of the Cervical Spine in Human OPLL-related Tissues and a Spinal Hyperostotic Mouse (ttw/ttw).

Immunohistochemical and real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. The aim of this study was to analyze the expression of five susceptibility genes (RSPO2, HAO1, CCDC91, RHPH9, and STK38L) for human ossification of the posterior longitudinal ligaments (OPLL) identified in a genome-wide association study. Detailed expression and functional studies for the five susceptibility genes are needed to aid in clarification of the etiology and pathogenesis of OPLL. Immunostaining, cell culture, and real-time RT-PCR were performed on ossified ligament samples collected during anterior cervical decompression for symptomatic OPLL (n = 39 patients) and on control non-OPLL samples (n = 8 patients). Immunohistochemical analysis in spinal hyperostotic mice (ttw/ttw) (n = 25) was also performed. The sample sections were stained for RSPO2, HAO1, CCDC91, RHPH9, STK38L, Runx2, Sox9, and CD90. The mRNA expression levels of the five susceptibility genes were also analyzed in cultured human OPLL and non-OPLL cells subjected to cyclic tensile strain. Immunoreactivity for RSPO2 and Sox9 was evident in proliferating chondrocytes in human OPLL tissues and ttw/ttw mice. Application of cyclic tensile strain to cultured human OPLL cells resulted in increases in mRNA levels for RSPO2, HAO1, and CCDC91. However, individual differences in expression in human OPLL-related samples were seen. HAO1-positive cells were detected only in 3- to 6-week-old ttw/ttw mice that did not simultaneously express RSPO2-positive samples. Among the five susceptibility genes, RSPO2, HAO1, and CCDC91 might be contributory factors in progression of OPLL. RSPO2 may be involved in endochondral ossification, especially in mixed or continuous type OPLL, HAO1 may be an initiation factor for OPLL that is rarely seen in mature human OPLL samples, and CCDC91 may be associated with progression of ossification caused by mechanical stress. These findings provide important insights into the pathogenesis and therapeutic targets for OPLL. N/A.

Crickets become behaviourally more stable when raised under higher temperatures

Developmental plasticity “prepares” individuals to environments experienced during adulthood. Labile traits, such as behaviour, vary within and among individuals owing to (i) reversible plasticity and (ii) developmental plasticity and genetic make-up, respectively. Here, we test whether developmental environments affect the expression of both within- and among-individual variation in behaviour. In ectothermic species, low temperatures are associated with a reduced expression of behaviour and can also limit the expression of reversible plasticity and among-individual differentiation, for example, by restricting the expression of additive genetic variation. We focused on exploratory behaviour since activity-related behaviours are assumed to be temperature-dependent in ectotherms. Specifically, low temperatures can restrict the physiological machinery needed for movement. To test our predictions, we raised field crickets, Gryllus bimaculatus, at low versus high temperatures throughout ontogeny and compared behavioural means and variance components (i.e. among- and within-individual variances) across treatments. We also compared the coefficients of variation for each variance component across treatments to assess whether environmental effects on variance were independent of the effects on mean behaviour. As predicted, individuals raised at high temperatures were more explorative and exhibited more among- and within-individual variance compared to individuals raised at low temperatures. Interestingly, individuals raised under high temperatures became more stable in their behaviour when controlling for treatment effects on average behaviour. Our results show experimentally that different developmental temperatures trigger different amounts of behavioural “stability” in exploratory behaviour, thereby suggesting a key role for temperature in affecting the ecological processes associated with exploratory behaviour in ectothermic species. Individuals differ relative to one another in their mean behavioural expression (i.e. “animal personality”), while, at the same time, individuals change their behaviour from one instance to the next (i.e. reversible plasticity). Expression of both above-mentioned components should strongly depend on environments experienced throughout ontogeny. Temperature represents a key environmental factor in most ectothermic animals as it directly affects the ability to express behaviour. Here, we experimentally test whether temperature experienced throughout ontogeny has permanent effects on the expression of individual differences and reversible plasticity in behaviour later in life. We show that individuals become more stable, i.e. express less reversible plasticity, in risky exploratory behaviour when raised under high temperatures. Our results thus suggest a key role for temperature in affecting the ecological processes associated with risky behaviours in ectothermic species.

Autonomic and Brain Morphological Predictors of Stress Resilience.

Stressful life events are an important cause of psychopathology. Humans exposed to aversive or stressful experiences show considerable inter-individual heterogeneity in their responses. However, the majority does not develop stress-related psychiatric disorders. The dynamic processes encompassing positive and functional adaptation in the face of significant adversity have been broadly defined as resilience. Traditionally, the assessment of resilience has been confined to self-report measures, both within the general community and putative high-risk populations. Although this approach has value, it is highly susceptible to subjective bias and may not capture the dynamic nature of resilience, as underlying construct. Recognizing the obvious benefits of more objective measures of resilience, research in the field has just started investigating the predictive value of several potential biological markers. This review provides an overview of theoretical views and empirical evidence suggesting that individual differences in heart rate variability (HRV), a surrogate index of resting cardiac vagal outflow, may underlie different levels of resilience toward the development of stress-related psychiatric disorders. Following this line of thought, recent studies describing associations between regional brain morphometric characteristics and resting state vagally-mediated HRV are summarized. Existing studies suggest that the structural morphology of the anterior cingulated cortex (ACC), particularly its cortical thickness, is implicated in the expression of individual differences in HRV. These findings are discussed in light of emerging structural neuroimaging research, linking morphological characteristics of the ACC to psychological traits ascribed to a high-resilient profile and abnormal structural integrity of the ACC to the psychophysiological expression of stress-related mental health consequences. We conclude that a multidisciplinary approach integrating brain structural imaging with HRV monitoring could offer novel perspectives about brain-body pathways in resilience and adaptation to psychological stress.

Attentional Control in Accidents Involving Agricultural Tractor Operators

Feature at a glance: Although a lack of safety features is often reported as the most important factor in tractor accidents, an accident per se is the outcome of many elements, including the amount of attentional control operators exert over the driving task. The lack of active attentional control is sometimes referred as “absentmindedness,” and many studies have investigated this phenomenon as the expression of individual differences. The present retrospective study represents a first attempt at investigating the relation between lack of attention and tractor accidents in a large sample of operators. The results show that attentional control is involved in tractor accidents, which can be taken as evidence of habit effects in operating agricultural machinery: Lower attentional control is required in routine actions, which makes expert operators more exposed to the possibility of making (skill-based) errors. This finding leads to suggestions for the design of future systems.

Size Matters – Correlation of Body Size, Structure of Sternal Glands and Mating Success in Echinothrips Americanus (Thysanoptera: Thripidae)

Females of many insect species analyse and select specific male signals for possible mates. Mate choice can benefit fecundity and survival of females, or have an indirect effect by providing optimal genes. Assortative mating by size is one of the most commonly observed sexual behaviors. Additionally, chemical cues may be detected by females, as these can also be indicators of body size and condition. Little is known about mate choice behavior among Thysanoptera. The mating system of Echinothrips americanus (Thysanoptera, Thripidae) is characterized by a strong competition for mates, leading to assortative mating. In this species very prominent gland structures are located on sternites III to VIII, of which the function still remains unknown. However, given the individual differences in expression of the gland release areas, a probable role in mate selection is postulated. In this study, we are interested in possible correlations between male body size, gland release areas, glandular substances, and mating success. Additionally, we used an experimental approach to test for a possible function in mate-assessment, or as an anti-aphrodisiac. Whereas pronotum length, distance between 1st and 2nd coxa, as well as total sternite area show a significant correlation with mating success, no direct correlation with sternal gland structures was observed. Furthermore, we failed to constitute a mate-assessment or anti-aphrodisiac-like function of sternal gland products.

A latent variable analysis of the Psychopathy Checklist-Revised and behavioral inhibition system/behavioral activation system factors in North American and Swedish offenders.

An influential neurobiological model of personality is the Reinforcement Sensitivity Theory, which postulates how basic motivational systems (behavioral activation system [BAS], behavioral inhibition system [BIS]) can help account for the development and expression of individual differences in personality. Earlier research has documented a link between psychopathic personality and the BIS/BAS scale (Carver & White, 1994), which was developed to measure the behavioral inhibition and activation systems. However, no studies have examined how latent BIS/BAS factors and the 4 empirically derived Psychopathy Checklist-Revised (PCL-R) psychopathy factors (Hare & Neumann, 2008) are associated across different cultures. In the current study, structural equation modeling was used to determine how the 4 PCL-R factors were able to predict BIS/BAS factors using 2 large independent samples of male offenders (North American N = 908; Swedish N = 242). The results were in line with theory and revealed a negative relationship between the PCL-R Affective factor and the BIS factor as well as positive relationships between the PCL-R Antisocial and Lifestyle factors with the BAS factor. Overall, the results of the current study provide evidence of cross-cultural generalizability for the associations between the PCL-R factors and the BIS-BAS factors. Taken together, the PCL-R psychopathy factors were able to account for meaningful variance in the BIS-BAS factors and further support a dimensional approach to understanding the psychopathy construct across cultures.

Infant Expressions in an Approach/Withdrawal Framework

ABSTRACTSince the introduction of empirical methods for studying facial expression, the interpretation of infant facial expressions has generated much debate. The premise of this article is that action tendencies of approach and withdrawal constitute a core organizational feature of emotion in humans, promoting coherence of behavior, facial signaling, and physiological responses. The approach/withdrawal framework can provide a taxonomy of contexts and the neurobehavioral framework for the systematic, empirical study of individual differences in expression, physiology, and behavior within individuals as well as across contexts over time. By adopting this framework in developmental work on basic emotion processes, it may be possible to better understand the behavioral principles governing facial displays, and how individual differences in them are related to physiology and behavioral function in context.

Human bitter perception correlates with bitter receptor messenger RNA expression in taste cells

Alleles of the receptor gene TAS2R38 are responsible in part for the variation in bitter taste perception of 6-n-propylthiouracil (PROP) and structurally similar compounds (eg, glucosinolates in cruciferous vegetables). At low concentrations, people with the PAV ("taster" amino acid sequence) form of TAS2R38 perceive these bitter compounds, whereas most with the AVI ("nontaster" amino acid sequence) form do not; heterozygotes (PAV/AVI) show the widest range of bitter perception. The objectives were to examine individual differences in expression of PAV-TAS2R38 messenger RNA (mRNA) among heterozygotes, to test the hypotheses that the abundance of allele-specific gene expression accounts for the variation in human bitter taste perception, and to relate to dietary intake of bitter-tasting beverages and foods. Heterozygous individuals (n = 22) provided psychophysical evaluation of the bitterness of PROP, glucosinolate-containing broccoli juice, non-glucosinolate-containing carrot juice, and several bitter non-TAS2R38 ligands as well as dietary recalls. Fungiform taste papillae were examined for allele-specific TAS2R38 expression by using quantitative polymerase chain reaction. PAV-TAS2R38 mRNA expression was measured in 18 of 22 heterozygous subjects. Relative expression varied widely and positively correlated with ratings of bitterness intensity of PROP (P = 0.007) and broccoli juice (P = 0.004) but not of the control solutions carrot juice (P = 0.26), NaCl (P = 0.68), caffeine (P = 0.24), or urea (P = 0.47). Expression amounts were related to self-reported recent and habitual caffeine intake (P = 0.060, P = 0.005); vegetable intake was too low to analyze. We provide evidence that PAV-TAS2R38 expression amount correlates with individual differences in bitter sensory perception and diet. The nature of this correlation calls for additional research on the molecular mechanisms associated with some individual differences in taste perception and food intake. The trial was registered at clinicaltrials.gov as NCT01399944.

Overdiagnosis of a typical carcinoid tumor as an adenocarcinoma of the lung: a case report and review of the literature

BackgroundOverdiagnosis of bronchopulmonary carcinoid tumors together with overtreatment can cause serious postoperative consequences for the patient. We report of a patient with a typical bronchopulmonary carcinoid tumor, which was initially misdiagnosed and treated as an adenocarcinoma of the lung. GnrH receptors and the associated Raf-1/MEK/ERK-1/2-pathway are potential targets for analogs in cancer treatment. We suspected a correlation between the lack of tumor growth, application of leuprolide and the Raf-1/MEK/ERK-1/2-pathway. Therefore, we examined GnrH receptor status in the examined specimen.Case presentationIn 2010 a 77 year-old male patient was shown to have a tumor mass of about 1.7 cm diameter in the inferior lobe of the left lung. Since 2005, this tumor had hitherto been known and showed no progression in size. The patient suffered from prostate cancer 4 years ago and was treated with TUR-P, radiation therapy and the application of leuprolide. We conducted an explorative thoracotomy with atypical segment resection. The first histological diagnosis was a metastasis of prostate cancer with lymphangiosis carcinomatosa. After several immunohistochemical stainings, the diagnosis was changed to adenocarcinoma of the lung. We conducted a re-thoracotomy with lobectomy and systematic lymphadenectomy 12 days later. The tumor stage was pT1 N0 MX G2 L1 V0 R0. Further immunohistochemical studies were performed. We received the results 15 days after the last operation. The diagnosis was ultimately changed to typical carcinoid tumor without any signs of lymphatic vessel invasion. The patient recovered well from surgery, but still suffers from dyspnea and lack of physical performance. Lung function testing revealed no evidence of impairment.ConclusionThe use of several immunohistochemical markers, careful evaluation of hematoxylin-eosin sections and the Ki-67 labelling index are important tools in discriminating between carcinoids and other bronchopulmonary carcinomas. Although we could not detect GnrH-receptors in the examined specimen, there may be individual differences in expression. GnrH receptor profiles in typical and atypical carcinoids should be scrutinized. This could lead to new therapeutical options, since the GnrH receptor has already been described on atypical carcinoids. Clinically tested drugs such as leuprolide could come to use.

California Psychological Inventory Dominance Scale Measurement Equivalence: General Population Normative and Indian, U.K., and U.S. Managerial Samples

The California Psychological Inventory’s Dominance scale was investigated for inconsistencies in item—trait associations across four samples (one American normative and three culturally dissociated manager groupings). The Kim, Cohen, and Park procedure was used, enabling simultaneous multigroup comparison in addition to the traditional differential item functioning focus on paired-group contrasts. Framing comparisons within Hofstede’s cultural dimensions, Dominance construct—item association inconsistencies were predicted to occur across Indian manager responses (when contrasted relatively with U.S. and U.K. responses). Results are consistent with the Hofstede predictions and have particular implications for empirically keyed assessments, multigroup contrasts, the cross-cultural expression of individual differences, and the generalizability of trait definitions across cultures.

Autoshaping in adolescence enhances sign-tracking behavior in adulthood: Impact on ethanol consumption

Autoshaping refers to a procedure during which a cue repeatedly paired with a reward elicits a conditioned response directed at either the reward delivery location (“goal-tracking”) or the cue itself (“sign- tracking”). Individual differences in expression of sign-tracking behavior may be predictive of voluntary ethanol intake. The present study was designed to explore the development of differences in sign-tracking behavior in adolescent and adult male and female rats in an 8-day autoshaping procedure. Consistency of sign-tracking and goal-tracking across age was examined by retesting adolescents again in adulthood and comparing their adult data with animals tested only as adults to explore pre-exposure effects on adult responding. In order to assess the relationship between sign-tracking and ethanol intake, voluntary ethanol consumption was measured in an 8-day, 2-hr limited access drinking paradigm following the 8-day autoshaping procedure in adulthood. Animals tested as adolescents showed notably less sign-tracking behavior than animals tested as adults, and sign-tracking behavior was not correlated across age. Animals exposed to the autoshaping procedure as adolescents demonstrated greater sign-tracking behavior as adults when compared to control animals tested only in adulthood. When examining the relationship in adulthood between sign-tracking and ethanol intake, an increase in ethanol intake among sign-trackers was found only in animals pre-exposed to autoshaping as adolescents. Whether or not these results reflect an adolescent-specific experience effect is unclear without further work to determine whether comparable pre-exposure effects are seen if the initial autoshaping sessions are delayed into adulthood.

Performance impairment consequent to sleep loss: determinants of resistance and susceptibility

Five years ago, it was first demonstrated that there are considerable, stable individual differences in performance impairment due to sleep deprivation. The discovery of this new phenotype, which has been labeled 'trototype', led to a surge of research activity aiming to identify predictors. Genes involved in the adenosinergic and circadian regulation of sleep have been identified as candidate predictors of individuals' resistance or susceptibility to performance impairment resulting from sleep deprivation. Furthermore, brain regions potentially involved in the expression of individual differences in vulnerability to sleep loss have been found. This research has provided new insights into the mechanisms underlying sleep/wake regulation and responses to loss of sleep. To date, however, it remains unknown how much of the phenotypic variability is explained by any of the putative predictors of trototype. The existence of substantial, phenotypic individual differences in performance impairment consequent to sleep loss has important implications for fatigue risk management in operational settings and for the symptomology and treatment of sleep disorders, putting a premium on the discovery of reliable predictors.

Individual Differences in Expressing and Perceiving Nonverbal Cues: New Data on an Old Question

Previous research on the link between individual differences in emotional expression and emotion recognition over six decades revealed widely varying results. A recent meta-analysis (Elfenbein & Eisenkraft, 2009) showed a positive correlation for displays elicited as intentional communication, but zero for naturalistic displays. However, the longstanding mystery dissipated interest, preventing work from using updated authoritative methods for studying individual differences. With Kenny’s (1994) Social Relations Model, we tested round robin groups in which each participant posed their emotions and later judged the expressions of each other member. The design included emotion inductions to increase expressers’ authentic experience. The resulting effect size, ρ=.51, r=.43, is larger than previously typical. Implications are discussed for theories on individual emotional skills.

Individual differences influence collective behaviour in social caterpillars

The expression of individual differences within a population often depends on environmental conditions. We investigated, first, whether there are differences between individual group-living forest tent caterpillars, Malacosoma disstria, that are expressed only in nutritionally unbalanced environments, and second, to what extent these individual behavioural differences influence the strategies used by the group to exploit food resources. We offered groups of caterpillars a binary choice between two equal food sources, either containing a balanced ratio of protein and carbohydrate or lacking digestible carbohydrate. Individual caterpillars responded to the diet treatment by becoming either inactive or active. The existence of these two behavioural categories was evident under dietary imbalance but not when foods were nutritionally balanced. At a collective level, the individual differences in behaviour led to colony decisions that were dependent upon the ratio of the two behavioural categories present in the group. Colonies comprising a majority of active caterpillars (‘active biased’) were less cohesive than inactive-biased colonies. Under dietary imbalance, active-biased groups did not focus their activity on one food source but split and exploited two sources at the same time. Since both food sources were nutritionally unbalanced, these groups grow less well than inactive-biased groups that remained on one food source. The coexistence of two foraging strategies may provide a compromise between maintaining colony cohesion and optimizing food location and diet balancing.

Biogenesis of Short Intronic Repeat 27-Nucleotide Small RNA from Endothelial Nitric-oxide Synthase Gene

Endothelial nitric-oxide synthase (eNOS) is a constitutively expressed gene in endothelium that produces NO and is critical for vascular integrity. Previously, we reported that the 27-nucleotide (nt) repeat polymorphism in eNOS intron 4, a source of 27-nt small RNA, which inhibits eNOS expression, were associated with cardiovascular risk and expression of the eNOS gene. In the current study, we investigated the biogenesis of the intron 4-derived 27-nt small RNA. Using Northern blot, we showed that the eNOS-derived 27-nt short intronic repeat RNA (sir-RNA) expressed only in the eNOS expressing endothelial cells. Cells containing 10 x 27- or 5 x 27-nt repeats produced higher levels of 27nt sir-RNA and lower levels of eNOS mRNA than the cells with 4 x 27-nt repeats. The 27nt sir-RNA was mostly present within the endothelial nuclei. When the splicing junctions of the 27-nt repeat containing intron 4 in the full-length eNOS cDNA vector were mutated, 27nt sir-RNA biogenesis was abolished. Suppression of Drosha or Dicer diminished the biogenesis of the 27nt sir-RNA. Our study suggests that the 27nt sir-RNA derived through eNOS pre-mRNA splicing may represent a new class of small RNA. The more eNOS is transcribed or higher number of the 27-nt repeats, the more 27nt sir-RNA is produced, which functions as a negative feedback self-regulator by specifically inhibiting the host gene eNOS expression. This novel molecular model may be responsible for quantitative differences between individuals carrying different numbers of the polymorphic repeats hence the cardiovascular risk.

Longitudinal modeling of genetic and environmental influences on self-reported availability of psychoactive substances: alcohol, cigarettes, marijuana, cocaine and stimulants.

Although an obvious environmental factor influencing drug use, the sources of individual differences in drug availability (DA) are unknown. This report is based on 1788 adult males from the Mid-Atlantic Twin Registry who participated in a structured telephone interview that included retrospective assessments of DA (cigarette, alcohol, marijuana, cocaine and stimulants) between ages 8 and 25. We fitted a biometric dual change score (DCS) model, adapted for ordinal data, to model latent growth and estimate the genetic and environmental components of variance over time. DA, despite being considered an environmental risk factor, is under both genetic and environmental control. For cigarette, alcohol, marijuana and cocaine availability, there was an overall increase in additive genetic variance and a decline in shared environmental variance over time. Non-shared environmental variance remained steady. Stimulant availability did not follow this pattern. Instead, there was an upswing in shared environmental effects with increasing age. We have modeled the genetic and environmental architecture of changes in DA across adolescence. The rise in additive genetic variance over time coincides with acceleration in the expression of individual differences, probably brought on by an increase in personal freedom and a reduction in social constraints. Understanding the etiology of DA is likely to reveal key components, acting directly or indirectly, in the pathway(s) leading to drug initiation, abuse and dependence.

Individual Differences in the Expression of Tyrosine Hydroxylase mRNA in Neurosecretory Neurons of the Human Paraventricular and Supraoptic Nuclei: Positive Correlation with Vasopressin mRNA

Previous studies indicated that in the human paraventricular nucleus (PVN) and in the supraoptic nucleus (SON) tyrosine hydroxylase (TH) – the first and rate-limiting enzyme in catecholamine synthesis – is localized mainly in magnocellular neurosecretory neurons. Individual differences were observed among control subjects in number and distribution of TH-immunoreactive (IR) perikarya, indicating that antemortem factors may regulate TH expression. Since a large number of TH-IR perikarya were observed in subjects who suffered from somatic illnesses leading to prolonged osmotic or nonosmotic stimulation of vasopressin (VP) release, we suggested that TH expression is related to the activation of VP neurons. The purpose of our study was to apply (1) in situ hybridization for TH mRNA on human PVN and SON to investigate how the previously reported individual differences in TH protein expression are depicted at the transcriptional level and (2) quantitative TH immunohistochemistry and in situ hybridization for VP mRNA throughout the dorsolateral part of the SON (dl-SON) in order to elucidate whether indeed expression of TH in neurosecretory nuclei depends on activation of VP neurons. Postmortem formalin-fixed, paraffin-embedded hypothalamic sections of 16 control subjects were studied for TH protein and TH and VP mRNAs. For 6 of the above cases, the number of TH-IR neurons and the total VP mRNA levels were estimated throughout the entire dl-SON using an image analysis system. Individual variation was observed in TH mRNA expression which appears to parallel the expression of TH-protein. Using Spearman’s bivariate test, a positive correlation was found between the number of TH-IR- and TH-mRNA-expressing neurons in both PVN and SON (p < 0.01) as well as between the number of TH-IR neurons and the total VP mRNA in the dl-SON (p < 0.05). Our results show (1) that the individual variability in the number of TH-IR neurons within the neurosecretory nuclei might be due to differential expression and/or stability of TH mRNA and (2) that expression of TH-immunoreactivity in human PVN and SON depends on the activation of VP neurons.

Isolation decreases physical and motivational aspects of morphine withdrawal

Environmental manipulations such as social housing conditions of animals may play a role in the expression of individual differences in response to drugs. This study aimed to evaluate whether isolated and grouped mice develop different degrees of morphine dependence. Isolated and grouped mice were rendered morphine dependent employing two different methods of induction: a fast or slow protocol, both reaching the same maximum daily dose (100 mg/kg). Naloxone-induced morphine withdrawal was assessed using a modified Gellert-Holtzman scale and a conditioned place aversion (CPA) procedure. Isolated animals manifested fewer signs of physical dependence than grouped mice and only those receiving two daily morphine doses presented significantly higher scores on the Gellert-Holtzman scale than controls. Similarly, in CPA, although all morphine-treated animals developed aversion, its intensity was only significantly higher than in controls in grouped animals receiving two daily doses. Analgesic response, measured with the hot-plate test, showed that isolated mice presented longer latencies to lick their paws (even without drug administration), suggesting that they had a higher level of endogenous opiates. It can be argued that isolated animals may be less sensitive to morphine than the non-isolated and therefore tolerate greater quantities or require more drug to produce the same effects. The results suggest that variability in the response to opiates could be affected by environmental manipulations.

The Nature and Nurture of Child Development

Although the reduction of child morbidity and the promotion of physical growth are important and necessary aspects of child development, these criteria by themselves do not define the adequacy of children's development. There are also behavioural-developmental criteria that emphasize the promotion of competence. the competent individual is one who can effectively adapt to and interact with his or her environment. Traits that define individual competence fall into five domains: cognitive skills, temperament/personality, motivation, self-perceptions, and interpersonal style. These domains are not completely independent, and there is at least partial overlap. the expression of individual differences in competence is partially moderated by context. Further, not all children achieve competence. Over time some children fall further and further behind their peers in their developmental course. in understanding what biological and psychosocial factors influence the development of individual differences in competence, four principles are critical.First, most aspects of individual competence are multidetermined. This means that interventions designed to facilitate development must be multifocal in nature, integrating influences from different domains. Second, influences upon children's development tend to be specific in nature. This emphasizes the importance of targeting specific interventions to specific outcomes. Third, individual developmental influences rarely operate in isolation from each other. Developmental risk factors tend to cluster together, as do developmentally protective influences. the extent of the impact of a given developmental risk factor will depend, in part, on the degree to which this risk factor covaries with other risk factors. Fourth, developmental risk and protective factors operate across time. Early exposure to developmental risks may increase the individual's susceptibility to later risk factors (sensitizing) or may limit the degree to which the individual can profit from later exposure to protective factors such as intervention (blunting). Early exposure to developmentally protective factors may attenuate the impact of later exposure to developmental risk factors (steeling).Principles underlying the nature and nurture of individual competence emphasize the need to use an IT-AT intervention strategy (Integrate Target Across Time). This means the need to integrate multi-domain interventions, target our intervention strategies to different contexts, risk conditions, and outcomes, and provide for recurring interventions across time to maximize the chances of long-term gains in individual competence.