Comparative Behavioral Correlation of High and Low-Performing Mice in the Forced Swim Test

Behavioral analysis in mice provided important contributions in helping understand and treat numerous neurobehavioral and neuropsychiatric disorders. The behavioral performance of animals and humans is widely different among individuals but the neurobehavioral mechanism of the innate difference is seldom investigated. Many neurologic conditions share comorbid symptoms that may have common pathophysiology and therapeutic strategy. The forced swim test (FST) has been commonly used to evaluate the “antidepressant” properties of drugs yet the individual difference analysis of this test was left scantly investigated along with the possible connection among other behavioral domains. This study conducted an FST-screening in outbred CD-1 male mice and segregated them into three groups: high performers (HP) or the active swimmers, middle performers (MP), and low performers (LP) or floaters. After which, a series of behavioral experiments were performed to measure their behavioral responses in the open field, elevated plus maze, Y maze, three-chamber social assay, novel object recognition, delay discounting task, and cliff avoidance reaction. The behavioral tests battery revealed that the three groups displayed seemingly correlated differences in locomotor activity and novel object recognition but not in other behaviors. This study suggests that the HP group in FST has higher locomotor activity and novelty-seeking tendencies compared to the other groups. These results may have important implications in creating behavior database in animal models that could be used for predicting interconnections of various behavioral domains, which eventually helps to understand the neurobiological mechanism controlling the behaviors in individual subjects.

Regional Cerebral Glucose Metabolism in Novelty Seeking and Antisocial Personality: A Positron Emission Tomography Study

Novelty seeking (NS) and antisocial personality (ASP) are commonly exhibited by those who suffer from addictions, such as substance abuse. NS has been suggested to be a fundamental aspect of ASP. To investigate the neurobiological substrate of NS and ASP, we tested the relationship between regional cerebral glucose metabolism and the level of NS, determining the differences between individuals with and without ASP. Seventy-two healthy adults (43 males, mean age±SD=38.8±16.6 years, range=20~70 years; 29 females, 44.2±20.1 years, range=19~72 years) underwent resting-state brain positron emission tomography (PET) 40 minutes after 18F-fluorodeoxyglucose (FDG) injection. Within 10 days of the FDG PET study, participants completed Cloninger's 240-item Temperament and Character Inventory (TCI) to determine NS scores. Participants with and without ASP were grouped according to their TCI profiles. Statistical parametric mapping analysis was performed using the FDG PET and TCI profile data. NS scores positively correlated with metabolism in the left anterior cingulate gyrus and the insula on both sides of the brain and negatively correlated with metabolism in the right pallidum and putamen. Participants with ASP showed differences in cerebral glucose metabolism across various cortical and subcortical regions, mainly in the frontal and prefrontal areas. These data demonstrate altered regional cerebral glucose metabolism in individuals with NS and ASP and inform our understanding of the neurobiological substrates of problematic behaviors and personality disorders.

Right Amygdalar Laterobasal Subregional Differences in Healthy Adults with Different Novelty Seeking Tendencies

OBJECTIVES: Novelty seeking (NS) represents a dopaminergically modulated tendency toward frequent exploratory activity. Considering the reports showing the relationship between exploratory activity and amygdalar function and structure, and the fact that amygdala is one of the key structures that constitute the dopaminergic pathway in the brain, amygdala might be closely related to NS tendencies. Amygdalar subregional analysis method, which has the enhanced sensitivity compared to the volumteric approach would be appropriate in investigating the subtle differences of amygdalar structures among healthy individuals. The aim of the current study was to examine whether amygdalar subregional morphometric characteristics are associated with the NS tendencies in healthy adults using the amygdalar subregional analysis method. METHODS: Twenty-six healthy adults (12 males, 14 females ; mean age 29.8 +/- 6.2 years) were screened for eligibility. All subjects completed the Korean version of the Temperament and Character Inventory (TCI) and underwent high-resolution brain magnetic resonance imaging. Individuals were divided into 2 groups according to NS scores of the TCI. RESULTS: Individuals of the high NS group had significantly larger laterobasal subregions in right amygdala, after adjustment with the brain parenchymal volumes. Sensitivity analyses for each potential confounding factor such as age, education years and Hamilton Depression Rating Scale (HDRS) scores demonstrated consistent results. CONCLUSIONS: This study suggests that NS differences are associated with the laterobasal subregion of the amygdala.

Correlation between novelty seeking personality of healthy young individuals and fractional anisotropy value of white matter / 中华行为医学与脑科学杂志

Objective To study the correlation between novelty seeking(NS) personality of healthy young individuals and fractional anisotropy (FA) with voxel-based analysis (VBA) of diffusion tensor imaging(DTI),and explore the microstructure of white matter of personality.Methods Total 333 healthy right handed volunteers completed the Chinese version of the TPQ and the Beck Depression Inventory(BDI),and then finished 3D T1 structure scan,DTI scan.All preprocessed DTI datum was analyzed with SPM8 soft ware in partial correlation analysis,using age and depression scores as controlled variable.The correlation studied between NS and FA (a voxel significance threshold P ＜ 0.001 and a cluster extent threshold of 30 voxels).Results NS score of men and women were 14.55 ± 4.66 and 14.08 ± 5.42 points,and the difference between the two groups was not statistically significant (t =0.81,P=0.46).BDI score of men were higher than that of women (t =3.10,P=0.002),which were 9.23 ± 7.90 and 6.76 ± 5.79 points respectively.NS correlated negatively with FA of the right inferior frontal gyrus,and the right supramarg(i)nal gyrus(P ＜ 0.001).Conclusion NS personality has specific microstructure background of white matter.

Relationship between novelty seeking phenotype and impulsive behavior in rats / 中华行为医学与脑科学杂志

ObjectiveTo investigate the relationship between novelty seeking and impulsivity behavior in rats.MethodsTwo models were used to test Novelty seeking,one was activity in a new environment model,the other was novel object preference model.And impulsivity was measured by T-maze.All rats(48) were used to examine the relationship between these two behaviour traits.ResultsNovelty seeking:the locomotor activities measured in a new environment for 30 min were (4695.58 ± 1579.87)cm,the exploring number of entries into the novel object area and time spending in the novel object area were respectively(20.92 ± 14.84)entries and (178.12± 135.22)s.Impulsivity:the average times of choosing low reward(LR) in the two test days were(4.71 ±2.71 ).Pearson product moment correlation was performed to investigate the relationship between these two behaviour traits,and the results suggested that there were notable correlation between novel object preference and impulsive decision making( r =0.295,P＜ 0.05 ),yet no significance were found between new environment activity and impulsive decision making.ConclusionNovelty seeking and impulsivity may be correlated with each other depending on different models.

The Association among the Genetic Polymorphism of Dopamine D4 Receptor, Temperament and Alcohol Drinking Behavior in Young Korean Adults

OBJECTIVES: The aim of this study is to explore the association among DRD4 polymorphism, temperament and alcohol drinking behavior of Koreans in their early adulthood. METHOD: Participants were 172 healthy Korean adults (mean age 28.1 +/- 0.8). Their temperament was assessed with the Temperament and Character Inventory (TCI) and their alcohol drinking behavior were evaluated with a self-reported questionnaire including the CAGE and the Korean version of Alcohol Use Disorder Identification Test (AUDIT-K). DRD4 exon III 48 base pair variable number of tandem repeats (VNTR) was genotyped by PCR. RESULTS: No significant association was found between DRD4 polymorphism and TCI temperament dimension (novelty seeking, harm avoidance, reward dependence, and persistence) as well as alcohol drinking behavior scales. However, novelty seeking was significantly associated with alcohol drinking behavior. The higher level of novelty seeking was associated with the higher severity index of drinking (B = -0.225, p < 0.001) and problematic alcohol use on the CAGE and AUDIT-K [Odds Ratio (OR) = 1.111, 95% Confidence Interval (CI) 1.021-1.209, p = 0.015, OR = 1.087, 95% CI 1.009-1.170, p = 0.028]. CONCLUSION: In our study, while there is no significant association of DRD4 polymorphism with temperament and alcohol drinking behavior, novelty seeking affects problematic alcohol use. Results suggest that novelty seeking may play an important role in problematic alcohol use in young Korean adults.

Alterações neuro-comportamentais em ratos machos adultos em modelos de programação pela hiperleptinemia na lactação / Neuro-behavioral alterations in adult male rats in programming models for hyperleptinemia in lactation

Existe uma grande associação entre alterações em parâmetros nutricionais, hormonais ou ambientais durante estágios iniciais da vida, particularmente durante os períodos gestacional e de lactação, e o surgimento de doenças crônicas na vida adulta tais como obesidade, diabetes, doenças cardiovasculares, ansiedade e depressão. Neste trabalho, foram avaliados os efeitos cognitivo-comportamentais, em ratos Wistar adultos, da administração de leptina (8ug/100g, dia, sc) durante os primeiros 10 dias de lactação: 1) diretamente nos filhotes; 2) nas progenitoras. A memória e o aprendizado, os níveis de comportamento associados à ansiedade e à busca pela novidade foram avaliados em animais adultos através, respectivamente, dos seguintes testes comportamentais: labirinto aquático radial de 8 braços, labirinto em cruz elevado e campo vazado. No primeiro modelo (injeção nos filhotes), foram observados altos níveis de ansiedade e de busca por novos estímulos, enquanto que a memória e aprendizagem e atividade locomotora não foram afetados. No segundo modelo (injeção nas progenitoras), foram detectados redução dos níveis de ansiedade e melhora no desempenho associado à memória e ao aprendizado. Porém, não houve diferença nos níveis de busca por novos estímulos e no nível de atividade locomotora. Também são observadas diferenças em parâmetros somáticos, endócrinos e metabólicos entre modelos. O primeiro modelo resulta em hiperfagia, maior peso corporal por aumento de massa magra, hiperleptinemia, hipertireoidismo, hipertrigliceridemia, hiperinsulinemia e hipoadiponectinemia, hipertensão, aumento de catecolamina e de corticosterona, além de resistência hipotalâmica à leptina. O segundo modelo induz hiperfagia e maior peso corporal por acúmulo de gordura, hiperleptinemia, hiperglicemia, eutireoidismo, normoinsulinemia e resistência central à leptina. As seguintes possibilidades podem explicar as diferenças cognitivos-comportamentais observadas entre os modelos estudados ...

A considerable association exists between variations in the gestational and lactation periods, and the appearance of chronic diseases in adult life, such as obesity, diabetes, cardiovascular diseases, anxiety and depression. In the present study, the cognitive and behavioral effects of leptin injection (8ug/100g/day, sc) during the first 10 days of lactation were evaluated in adult male Wistar rats. In the first part of the study, leptin was injected directly in the offspring. In the second part of the study, leptin was injected in the lactation dams. Memory and learning, levels of anxiety-like behavior and levels of novelty-seeking behavior were evaluated by testing animals in, respectively, the radial-arm water maze, the elevated plus maze and the hole board arena. In the first model (offspring injection), high levels of anxiety and of novelty-seeking behavior were observed. Memory/learning and locomotor activity were unaffected. In the second model (dam injection), reduced levels of anxiety and better memory/learning performance were observed. Conversely, novelty-seeking and locomotor behavior were unaffected. Differences between models regarding somatic, endocrine and metabolic parameters are also observed. The first model presents hyperphagia, higher lean body mass, hyperleptinemia, hyperthyroidism, hipertrigliceridemia, hiperinsulinemia and hypoadiponectinemia, hypertension, increased levels of catecholamines and corticosterone, and hypothalamic leptin resistance. The second model induces hyperphagia, higher body mass, thou by accumulation of fat, hyperleptinemia, hyperglycemia, euthyroidism, normoinsulinemia and central mechanism of leptin resistance. The following possibilities may explain the cognitive-behavioral differences observed between models in the present study: 1) differences in somatic, endocrine and metabolic parameters; 2) modifications of the relationship between dams and their offspring, since leptin injection in the dams may reduce ...

Association between Dopamine Receptor D4 Polymorphisms and Novelty Seeking Personality Trait in a Korean Population / 신경정신의학

OBJECTIVES: We investigated the relationship of personality traits with dopamine D4 receptor(DRD4) exon III polymorphism in a Korean population. METHODS: We analysed DRD4 exon III 48-bp repeats polymorphism in 173 Korean healthy female adolescents(age=13.88+/-0.29 years) who also completed Temperament and Character Inventory(TCI). RESULTS: Novelty seeking score of the TCI was significantly higher in the subjects with DRD4 long alleles(>or=5 repeats) compared with the subjects without these(t=2.11, p=0.037). CONCLUSION: The present study supports the previous reports that long repeats of the DRD4-exon III polymorphism are related with Novelty Seeking personality.