Rostral midbrain lesions and copulatory behavior in male rats

Discrete electrolytic lesions were placed in the mesencephalic dorsal noradrenergic (DNE) bundle of 22 male Sprague-Dawley rats, and sham operations were performed on 14 control animals. Eight components of copulatory behavior were compared in 2 preoperative and 2 postoperative heterosexual mating tests. A significant postlesion decrease in the postejaculatory interval (PEI), number of intromissions, number of incomplete mounts and the ejaculation latency from the first intromission (ELI) occurred. Norepinephrine levels were significantly reduced in the hippocampus, amygdala and hypothalamus, but not in the preoptic area. The only statistically significant correlations between NE concentrations and behavior in the lesioned animals were negative (hippocampal NE with PEI and ELI). The results support the hypothesis that rostral midbrain lesions disinhibit some components of male rodent copulatory behavior, but suggest that a system or systems other than the DNE bundle may be responsible for this disinhibition.     

Development of olfactory-guided behavior in the golden hamster.

Hamster pups were tested for an odor preference every day from 1-16 days of age with shavings from their home cage and with clean wood shavings. The hamster pups showed a clear preference for their home cage shavings by 8 days of age. They were then tested for preferences with other odor combinations. Tests for preference with other odor pairs indicate that this preference is due to a change in the hamsters rather than a change in the stimulus. In these tests the hamster pups did not demonstrate a preference for their home shavings over shavings in which a nonlactating female had lived. Further tests will have to be done to determine how specific the hamster pup's olfactory preferences are.     

青少年网络行为问卷的编制及信效度分析

目的:编制青少年网络行为问卷,为系统评估网络成瘾青少年的网络相关行为特点提供工具。方法:通过开放式访谈和文献复习,建立问卷的初始条目库。采用探索性因素分析技术筛选条目。在湖南永州和长沙市分别取样490例和606例,进行问卷的有关信效度检验。结果:青少年网络行为问卷最终由56个条目构成,其中反映网络使用时间和上网条件等一般情况的条目16条,余40个条目可归纳为9个因子,分别为信息与技术、性与游戏、娱乐放松、网络人际关系、网络效能感、对网络的积极评价、消极评价、上网焦虑、网络满意度。9因子累计可解释方差变异的51.651%。验证性因素分析表明,9因子结构拟合良好,χ2/df=2.780,NFI=0.961,RFI=0.957,IFI=0.975,TLI=0.972,CFI=0.975,RMSEA=0.054。除少数分量表外,各分量表的"系数和重测相关系数较高。结论:青少年网络行为问卷具有较好的结构效度和信度。其实证效度有待进一步检验。     

Changes in estrogen and progestin receptor binding resulting from retrochiasmatic knife cuts

Retrochiasmatic frontolateral knife cuts (FLC) or sham operations (Sham) were performed with a Halasz-type knife. All animals were primed with estrogen plus 0.5 mg progesterone (P) and tested for lordosis both before and after surgery. Two weeks after the last test they received estradiol (E₂) in Silastic capsules and were sacrificed 2 days later for determination of either nuclear estrogen receptors or cytosol progestin receptor binding in brain and pituitary (PIT). Rats which had received FLC showed significantly lower lordosis quotients relative to Shams, and relative to their own pre-surgery scores. Nuclear E₂-receptor binding was significantly reduced in the hypothalamus (HYPO) following FLC, but not in preoptic area (POA) or PIT. No changes in cytosol P-receptor binding were observed in HYPO, POA or PIT following FLC. Our results suggest a positive correlation between the number of hypothalamic E₂-receptors and the capacity to display lordosis, and emphasize the importance of anterolateral connections to the HYPO for the progesterone-induced facilitation of lordosis.     

Minority mating advantage of certain eye color mutants ofDrosophila melanogaster. I. Multiple-choice and single-female tests

Alleles at the brown locus ofDrosophila melanogaster combined with homozygous scarlet provide a useful model to demonstrate minority advantage of males in mating. Heterozygotes with orange (O) eyes equal in numbers to homozygotes with red (R) eyes (1010 in both sexes) displayed no bias favoring either eye color, but each eye color was favored when males occurred in a minority ratio (218). In direct observation of single females with equal numbers of males (33) as controls,O males courted less and more slowly thanR males, but females mated with either type without bias. When unequal (41), the minority males were successful at more than twice the frequency expected. Whether successful or not, the minority males did not change their level of courtship, and thus cannot be said to compensate for their frequency in any way. The time between first courtship and mating was less for the minority males than for the majority males. We discard the hypothesis that the minority male will be accepted immediately or ahead of a majority male, because the opposite tended to occur: that if a minority male courted first he was less likely to be successful than if he waited until the majority courted. Our results then are in conformity with the hypothesis that a female samples males and their courtship cues, thus becoming habituated to the majority of the first courting male, but she accepts a male with a cue different from that which she originally detected but avoided. That male is most often the minority.This research was supported in part by National Science Foundation Grants GB-34206 to August 31, 1974, and BMS 72-02110 after that date.     

Effects of placentation on selected type A behaviors in adult males in the national heart,lung, and blood institute (NHLBI) twin study

A dermatoglyphic index derived from monozygotic (MZ) twins of known placental type was used to estimate placentation retrospectively in a sample of adult male MZ twins. Examination of behavioral test scores with respect to placentation showed that the within-pair difference of most measures of type A behavior was smaller in presumed monochorionic than presumed dichorionic pairs. Measures of cognitive function and hostility were not related to placental type. Intraclass correlations in the monochorionic subgroup of MZ twins were greater than the correlations reported for the full sample of MZ twins. The trends were strongest for the Adjective Check List scales taken at two different exams 5 years apart and, to a lesser extent, for the Framingham type A scale. Our results are most consistent with greater intrauterine environmental covariance in monochorionic MZ twins as an explanation for inflation of the MZ twin correlation relative to dizygotic (DZ) correlation reported for some type A measures.     

Genetic and light intensity effects on the activity and emigratory behavior of the house fly,Musca domestica (L.)

The emigratory behavior and locomotor activity of yellow-eyed (y/y), wildtype (+/+), and heterozygous (+/y) house flies was examined at 8 fc (86 lx) and 1600 fc (17,223 lx) light intenstities. At 8 fc, emigration rate and activity of the y/y flies was similar to that of the +/+ and +/y flies. However, at 1600 fc, the y/y flies emigrated at twice the rate and showed an activity of about one-third that of the other genotypes. The behavior of the +/+ and +/y flies remained similar regardless of the experimental design or light intensity. The excessive neural stimulation by high-intensity light resulting from reduced shielding pigments led to behavioral modifications in the visual and tactile responses of the y/y flies.This research was supported in part by grants from the CUNY Faculty Research Award Program (No. 1103) and NIH Biomedical Research Support Grant 5-S05-R-07064.     

Genetic analysis of cercarial emergence rhythms ofSchistosoma mansoni

Using two chronobiological variants ofSchistosoma mansoni (a blood fluke infecting man) from Guadeloupe (French West Indies), we carried out experimental crossbreeding between schistosomes with an early and those with a late cercarial shedding pattern. The results obtained on the F₁ (intermediate shedding patterns) and F₂ generations (early, intermediate, and late patterns) demonstrate that the cercarial emergence rhythms of schistosomes are genetically determined. This genetic variability is interpreted as a consequence of the selective pressure exerted by the two different hosts (man and rat) implicated in the life cycle ofS. mansoni from the Guadeloupean focus of schistosomiasis.This work received financial support from the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases and the CNRS.     

Development of feminine sexual behavior in the rat: Androgenic and temporal influences

The contributions of prenatal and postnatal androgen exposure upon the development of sexual behavior in rats were examined by prenatal treatment of pups with an androgen antagonist (flutamide) and postnatal androgenization or castration. Male and female rats were exposed to the androgen receptor-blocker flutamide (FLU) in utero via prenatal injections to the mother on Days 10 through 22 of gestation. At birth (Day 1) males were castrated. Both males and females were injected with either 100 μg testosterone propionate (TP) or oil on Day 1. In adulthood all gonadectomized animals were tested for the display of feminine sexual behavior (lordosis) in response to a range of estrogen dosages. Prenatal exposure to FLU enhanced lordosis in both sexes when compared to vehicle-treated controls. Postnatal TP treatment decreased lordotic potential as expected. However, in animals given TP postnatally, those receiving prenatal flutamide had higher lordosis quotients than animals receiving vehicle treatment. These data confirm (1) that the development of feminine sexual behavior is inhibited by androgen exposure, (2) that such exposure occurs prenatally, (3) that the potential for feminine behavioral differentiation occurs prenatally as well as postnatally, and (4) that androgen acts perinatally to affect estrogen sensitivity in adulthood.