Agonistic behavior and social reactivity of LG/J mice in both an arena and a seminatural setting

In order to determine the relatively long-term effects of having been primed for agonistic behaviors in an arena setting, 28 male LG/J mice were observed for these behaviors in a seminatural environment for a period of 5 days following a 20 min arena test. The mice were first placed in an arena in which they were allowed either immediate physical contact with another strain (control condition) or were briefly separated from another strain by a transparent partition before being allowed physical access to them (priming condition). Subjects, recorded as either having fought or not fought in the arena, were then placed in a 101 cm square seminatural setting. Seven trials, using 8 LGs each (4 arenaexperienced males and 4 naive females), were made, and agonistic behaviors were recorded for the priming and control condition subjects. The results showed that the control condition fighters (CF) like the priming condition fighters (PF) fought in the arena situation, but different agonistic patterns in the seminatural setting were noted. While in the seminatural environment, both CF and PF mice were attacked frequently and submitted frequently, but PF mice attacked opponents more frequently than did CF subjects (p < 0.025) and elicited significantly more submissions from opponent mice than did CF mice (p < 0.025). It is concluded that: (1) there are more and different agonistic behavior patterns available in the more natural environment than in the arena setting, and more specifically (2) there is a greater effect on agonistic behaviors in a seminatural environment for mice that fought when exposed to the arena priming procedure as compared with mice having fought in the arena control condition.     

Endocrine and emotional response to exclusion among women and men; cortisol,salivary alpha amylase,and mood

Background and Objectives: Social exclusion is ubiquitous and painful. Evolutionary models indicate sex differences in coping with social stress. Recent empirical data suggest different sex patterns in hypothalamic–pituitary–adrenal (HPA) and sympathetic–adrenal–medullary (SAM) reactivity. The present study sought to test this hypothesis.

Design: We examined differences in endocrine and emotional response to exclusion by using a virtual ball tossing paradigm (Cyberball). Saliva samples and mood ratings were collected to reflect levels before, and repeatedly following, exclusion.

Methods: The sample included 21 women and 23 men. Cortisol and salivary alpha amylase (sAA), biomarkers of the HPA and SAM systems, respectively, were used as indices of two arms of stress response.

Results: Following exclusion, all participants experienced mood worsening followed by mood improvement, with men reporting less distress than women. Women evinced decline in cortisol following the Cyberball task, whereas men’s cortisol levels showed a non-significant rise, and then decline, following exclusion.

Conclusions: Our results concur with previous findings showing SAM reactivity to be gender-neutral and HPA reactivity to be gender-divergent. Additional studies are needed to examine sex-specific response to social exclusion. Implications for individual differences in recovery from stress are discussed.     

Interactions between the effects of food and water motivating operations on food‐ and water‐reinforced responding in mice

Two experiments examined interactions between the effects of food and water motivating operations (MOs) on the food‐ and water‐reinforced operant behavior of mice. In Experiment 1, mice responded for sucrose pellets and then water reinforcement under four different MOs: food deprivation, water deprivation, concurrent food and water deprivation, and no deprivation. The most responding for pellets occurred under food deprivation and the most responding for water occurred under water deprivation. Concurrent food and water deprivation decreased responding for both reinforcers. Nevertheless, water deprivation alone increased pellet‐reinforced responding and food deprivation alone likewise increased water‐reinforced responding relative to no deprivation. Experiment 2 demonstrated that presession food during concurrent food and water deprivation increased in‐session responding for water relative to sessions where no presession food was provided. Conversely, presession water during concurrent food and water deprivation did not increase in‐session responding for pellets. These results suggest that a) the reinforcing value of a single stimulus can be affected by multiple MOs, b) a single MO can affect the reinforcing value of multiple stimuli, and c) reinforcing events can also function as MOs. We consider implications for theory and practice and suggest strategies for further basic research on MOs.     

The influence of sex hormones on functional cerebral asymmetries in postmenopausal women

Studies investigating changes in functional cerebral asymmetries (FCAs) with hormonal fluctuations during the menstrual cycle in young women have led to controversial hypotheses about an influence of estrogen (E) and/or progesterone (P) on FCAs. Based on methodical, but also on principal problems in deriving conclusions about hormone effects from correlational designs, the present study investigated hemispheric asymmetries in postmenopausal women, who received hormone replacement either with E alone (E group, n = 32), an E–P combination (E–P group, n = 29) or no hormone substitution (control group, n = 31). Speed and accuracy of responses to a word- and a face decision task, both presented laterally by means of the visual half field technique, were assessed. The control group showed the typical pattern of hemispheric asymmetry with more correct responses to verbal stimuli presented in the right visual field (RVF) and to face stimuli presented in the left visual field (LVF). A hormone-effect was demonstrable only for the verbal task, in which the E group showed an enhanced performance of the right hemisphere (LVF). The E–P group showed no significant differences to the control group or the E group. The results suggest a role of E in the modulation of FCAs at least with regard to verbal processing.     

Apodemus sylvaticus (LOXT) is a suitable mouse strain for testing spatial memory retention in the Morris water maze

Information on the difference in cognitive function between laboratory and wild-caught mice is anecdotal and this question has not been systematically studied. Moreover, studying a wild-caught mouse strain per se may add information to the repertoire of mouse strains available. We aimed to study spatial memory in a wild mouse strain (Apodemus sylvaticus, AS) as compared to two individual laboratory mouse strains.Male AS (n = 20), CD1 (n = 19) and C57BL/6J mice (n = 19), 12–14 weeks old, were used in the experiments. The Morris water maze (MWM) was used for determination of spatial memory and time spent in the target quadrant at time points 5 (D5) and 12 days (D12) was evaluated. During the acquisition phase latency to reach the platform and path length to reach the platform was evaluated.Following four training days on day 5 (D5), time spent in the target quadrant was highest in AS > CD1 > C57BL/6J (P < 0.006). On day 12 (D12), time spent in the target quadrant was significantly higher in AS than in both other strains (P < 0.001).All animals learned the task and during the acquisition phase, latency to reach the platform as well as path length decreased significantly in AS.It is concluded that the AS is the most suitable strain for the evaluation of spatial memory in the MWM and is presenting with memory retention superior to laboratory mouse strains CD1 and C57BL/6J.     

Adolescent Neurodevelopment and Psychopathology

Adolescence is a high-risk period for the onset of psychopathology. The occurrence of depression increases markedly in the years following the onset of puberty, and most individuals who are eventually diagnosed with a psychotic disorder show a marked rise in adjustment problems during adolescence. It is well established that puberty involves increases in the secretion of gonadal hormones. More recently, research has shown that stress hormones show a similar normative rise following puberty. Accumulating findings indicate that the postpubescent period is also characterized by significant neurodevelopment; there are changes in brain structure and function that are partially a consequence of hormonal factors. Researchers are now challenged to elucidate the neural mechanisms relating postpubertal neurodevelopment with the elevations in risk for psychopathology that characterize adolescence. One plausible mechanism is the effect of hormones on gene expression. The normal neuromaturational processes observed in adolescence partially reflect the effect of gonadal hormones on the expression of genes that control brain development. Hormone surges following puberty may also trigger the expression of genes that code for brain abnormalities that give rise to mental disorders.     

不同程度尿蛋白患者血清甲状腺激素水平变化及其临床意义

探讨不同程度蛋白尿患者血清甲状腺激素水平的变化及其临床意义。66例不同程度蛋白尿患者,肾病综合征组28例,非肾病综合征组38例,健康对照组60例。发现蛋白尿水平与甲状腺激素水平尤其是FT3水平关系密切。在肾病综合征患者,主要表现为FT3显著降低,提示肾病综合征是正常甲状腺病态综合征的一种。     

A qualitative aspect of learning-sensitive open field ambulation in mice

Maze training was shown to affect qualitative aspects of the learning-sensitive open-field (OF) ambulation in male Swiss albino mice. The changes in thigmotactic (wall-seeking) behaviour were most pronounced when significant signs of learning occurred, usually on the third day of training. Also daily changes in thigmotaxis from before to after training were found. Mice not subjected to maze training exhibited a different thigmotactic pattern of behaviour. The present series of experiments indicated that separate starting-points (centre or wall) influenced the thigmotactic behaviour as opposed to the shape of the OF (circular or square).     

认知与情绪过程的脑诱发电位研究——情绪的适应性假说

本研究观测了30名女性被试在月经周期中的不同激素时相对图像刺激的情绪价值的主观评估和脑诱发电位反应。调节刺激的情绪价值的五类幻灯片分别为普通人像、婴儿像、皮肤病人像、男模特儿像和女模特儿像。实验发现只有脑诱发电位的P3成份随刺激的情绪价值和激素的时相而变化。被评为喜爱与不喜爱的图像(婴儿像和皮肤病人像)所诱发的P3波在幅度上均明显高于中性图像(普通人像)所致的P3反应。在高孕激素时相,对婴儿像和男模特儿像的P3反应高于在低孕激素时相对同类刺激的P3反应。高孕激素时相还伴有对各类图像性感程度评估值的降低。对各类图像喜爱程度的评估则随雌激素水平的上升而增高。上述实验结果表明,P3波敏感于刺激的情绪价值并反映了认知与情绪过程中受生理状态调节的适应性变化。