Responsiveness to estrous chemostimuli in male rats (Rattus norvegicus) of different ages

Previous findings indicate that Norway rats (Rattus norvegicus) respond differentially to estrous chemostimuli in early infancy and that adult male sexual responsiveness to such chemostimuli depends on infantile experience with suckling odors (Fillion & Blass, in press). The development of behavioral responsiveness to estrous chemostimuli in male rats from late infancy to adulthood was examined in this study. Preweanling, adolescent, and adult males were observed for 20 min in the presence of an anesthetized estrous or an anesthetized diestrous female. This was, for adolescent and adult subjects, the first heterosexual encounter since weaning. Rats in each age-group responded differentially according to female state, but in distinct, age-related ways. Preweanling spent more time investigating the female's body if she was estrous. Adults expressed the same affinity but by more focused investigation directed perivaginally. Adolescents showed no female-directed bias but groomed themselves more if the female was estrous. These data identify developmental continuities and discontinuities in male rat behavior toward sexually receptive females.     

Olfactory discrimination of estrous condition by the male golden hamster (Mesocricetus auratus)

After repeated exposure to receptive and nonreceptive females, male golden hamsters were tested for olfactory preferences in a four-choice olfactometer. Males discriminated between the odor of anesthetized females in different stages of their estrous cycle when the airstreams carrying the stimulus odors were diluted. Previous failures to demonstrate such an ability were probably due to ceiling effects resulting from laboratory testing. Males preferred the odor of females on the day before receptivity (a day coincident with maximal scent marking by the female) and least preferred the odor of females on diestrus-1 (the day on which females attacked and chased males during pretesting encounters). Detection and quick response to an impending estrus would be especially important for males of a solitary and promiscuous species in which there is a first male mating advantage.     

Effects of opiate antagonists on spatial memory in young and aged rats

The effects of post-training opiate antagonist administration on spatial memory were assessed in young and aged male Long Evans rats. In Experiment I rats were trained to visit each arm of an eight-arm radial maze once in a session to obtain a food reward placed at the end of each arm. During training aged rats required significantly more trials to achieve criterion performance when compared to young mature rats. However, administration of the opiate antagonist naloxone (2.0 mg/kg) immediately after each training trial did not significantly alter the rate of achieving accurate performance in either age group. In Experiment II young and aged rats that were previously trained to a comparable criterion on the radial maze were tested on the same maze apparatus in novel spatial environments. When animals were exposed to novel spatial information, the effects of post-trial opiate antagonists were examined using a within-subjects counter-balanced design. In Experiment IIa naloxone (2 mg/kg) enhanced the performance of both young and aged rats. In Experiment IIB naltrexone (1.0 mg/kg) was found to have a comparable effect of enhancing the performance of both age groups. In addition, in Experiment IIb a significant age-related deficit was found in rats tested in novel spatial environments. These results indicate that opiate antagonists are capable of improving memory for new spatial information in both young and aged rats on a task that is sensitive to behavioral deficits during normal aging.     

Unconditioned sexual incentive motivation in the male Norway rat (Rattus norvegicus)

Sexual incentive motivation was evaluated in a procedure consisting of a large open field where incentive animals were confined behind wire mesh openings. When sexually inexperienced male rats (Rattus norvegicus) were exposed to the receptive female-male incentives, they spent more time close to the female. If the incentives were receptive female-nonreceptive female, the receptive female was preferred. However, when the alternatives were nonreceptive female-male, no preference was obtained. Castration abolished preference for the receptive female, and treatment with testosterone propionate restored it. Estradiol plus oil is as efficient as estradiol plus progesterone for giving the ovariectomized female incentive properties. The living female can be replaced with female odor. Sexual experience did not have any long-term effects on the female's incentive value, but immediately preceding limited sexual activity enhanced it     

Conditioned suppression of the proboscis-extension response in young, middle-aged, and old Drosophila melanogaster flies: acquisition and extinction

Young (7 days old), middle-aged (30 days old), and old (50 days old) Drosophila melanogaster males were used in an inhibitory conditioning of the proboscis-extension response. Two reinforcement schedules were applied, constant vs. partial. Partial reinforcement increased the number of trials needed to reach the learning criterion to the same extent in all age groups. Young flies needed fewer trials to reach the criterion than both middle-aged and old flies, which did not differ from each other. Extinction was delayed in the partial reinforcement groups by the same amount in all age groups. The slowest rate of extinction was observed in the old group and the fastest for the middle-aged flies. The results are discussed in connection with hypotheses that consider extinction an index either of behavioral rigidity or of strength of the initial learning.     

The influence of aging on poststroke depression using a rat model via middle cerebral artery occlusion

Poststroke depression (PSD) is the most frequent psychological sequela following stroke. While previous studies describe the impact of age on brain infarct volume, brain edema, and blood–brain barrier (BBB) breakdown following ischemia, the role of age on PSD has yet to be described. Here, we examine the influence of age on PSD progression in a rat model of PSD by middle cerebral artery occlusion (MCAO). One hundred forty-three rats were divided into three groups. 48 rats 20 weeks of age underwent a sham procedure, 51 rats 20 weeks of age had MCAO, and 44 rats 22–26 months of age had MCAO. Groups were further divided into two subgroups. The first subgroup was used to measure infarct lesion volume, brain edema, and BBB breakdown at 24 h. In the second subgroup at 3 weeks after MCAO, rats were subjected to a sucrose preference test, two-way shuttle avoidance task, forced swimming test, and a brain-derived neurotrophic factor (BDNF) protein level measurement. Total and striatal infarct volume, brain edema, and BBB breakdown in the striatum were increased in older rats, as compared with younger rats. While both old and young rats exhibited depressive-like behaviors on each of the behavioral tests and lower BDNF levels post-MCAO, as compared with control rats, there were no differences between old and young rats. Although older rats suffered from larger infarct volumes, increased brain edema and more BBB disruption following MCAO, the lack of behavioral differences between young and old rats suggests that there was no effect of rat age on the incidence of PSD.     

Developmental analysis of human figure drawings in adolescence, young adulthood, and middle age.

Analyzed 195 human figure drawings (HFDs) of adolescents, young adults, and middle-aged adults in terms of developmental differences in anxiety signs, grouped into aggressive-hostile and insecure-labile categories, and according to sex-role stereotype, as measured by the Broverman Sex-role Stereotype Scale. Adolescent males and females were significantly more likely to obtain more anxiety signs than the two adult groups, although young adults and middle-aged adults did not differ from one another in HFD performance. The most reliable sex difference was that males reveal significantly more aggressive-hostile indices in the HFDs relative to females; no significant sex differences were obtained for number of insecure-labile indices. The degree to which one has adopted a conventional sex-role stereotype was not predictive of anxiety sign differences in HFD performance for either sex or for any age group.     

Alcohol and Male Acceptance of Sexual Aggression: The Role of Perceptual Ambiguity1

The present study assessed the effects of drinking and behavioral ambiguity on perceptions of sexual aggression. Male participants, randomly assigned to 1 of 4 alcohol conditions (low, moderate, placebo, or control) viewed a videotaped interaction involving a couple meeting before a blind date. In the receptive condition, the female was friendly and excited. In the nonreceptive condition, she showed rigid posture and lacked enthusiasm. Participants then judged the acceptability of sexual aggression against the female and the attribution of the female's responsibility. Findings indicated a significant interaction such that in the receptive condition, higher alcohol doses elicited both greater acceptance of sexual aggression and greater attribution of female responsibility. There was no impact of alcohol dosage in the nonreceptive condition.     

Gender-specific social experiences and the development of aggressive and sexual behavior in male mice

This study examined influences of gender-specific social experiences on the development of aggressive and sexual behavior in male mice. To determine the effects of gender-specific social experience three different types of groups were constituted after the animals had been weaned. The subjects were randomly assigned to different treatments. Female groups were composed of one experimental male and three female cohabitants. Male groups were composed of five experimental males each, and the mixed-sex groups were composed of two experimental males and of two females. The experimental subjects stayed in these groups until the age of approximately three months, when the testing for sexual and aggressive behavior commenced. For the sexuality tests, a receptive female was placed in the home cage of the experimental male for ten minutes. A nonaggressive male was placed in the home cage of the experimental male for seven minutes for the aggression tests. The experimental males were administered both sexuality and aggression tests, the sequence of testing sexual and aggressive behavior was systematically varied in order to control the influence of the two different types of behavioral tests. The results showed that males with only male social experiences showed fewer responses and were less active in both the aggression and sexuality tests than the males from the two other types of groups. Significant positive correlations between activity during aggression and sexual tests were obtained for all three groups. © 1994 Wiley-Liss, Inc.     

Emotional trauma in rats: Age as a factor in recovery

Old (7 months of age) and young (2 months) male rats were divided into groups matched for spontaneous exploratory activity and for age. Experimental rats in the two age categories were then traumatized by giving them a 90 volt shock to the feet for two sec. on only one occasion. It was shown that nearly all the young rats recovered from the trauma within 5 weeks, as measured by brief exploratory activity and defecation, while at the end of 6 months the old rats still had not recovered. These results point up the greater resiliency of young animals, and the need for caution in the interpreting of research and theories on early experience.     

Rapid forgetting of social transmission of food preferences in aged rats: relationship to hippocampal CREB activation

A major characteristic of age-related changes in memory in rodents is an increase in the rate of forgetting of new information, even when tests given soon after training reveal intact memory. Interference with CREB functions similarly results in rapid decay of memory. Using quantitative immunocytochemistry, the present experiment examined the number of CREB- and pCREB-immunoreactive neurons in three regions of the dorsal and ventral hippocampus (dentate gyrus, CA3, and CA1) as a function of age and training. Rats were trained in a social transmission of food preference task. Using different food pairings, memory was tested in each rat immediately and 1, 2, 3, and 7 d later. Both young and old rats had intact and comparable memory scores at the immediate and 24-h tests, but old rats exhibited more rapid forgetting thereafter relative to that of young rats. The main findings were that training resulted in large increases in the number of pCREB-immunoreactive cells throughout the hippocampus in both young and aged rats. However, particularly in the ventral hippocampus, the training-elicited increase in pCREB-positive neurons was significantly lower in old than in young rats. Based on Western blot analyses in a separate set of rats, CREB levels were not responsive to training but were lower in the ventral hippocampus of old rats than of young rats. The present findings suggest that lower activation of CREB after training may contribute to the rapid forgetting seen in aged rats.     

The Effects of Age,Sex and Alzheimer's Disease on Strategy Use During Verbal Fluency Tasks

ABSTRACT

Clustering and switching strategies during phonemic and semantic verbal fluency tasks were investigated in healthy adults (n = 193, 86 males, 20–90 years) in young, middle-aged, young–old, and old–old age groups (Study 1). Older groups produced fewer total words and lower switching scores; males relied more on clustering and females on switching to produce equivalent output. In Study 2, early Alzheimer's disease participants, compared to healthy older adults, (n = 26 per group) produced fewer total words and smaller average clusters. Sex, age, and clinical differences on switching and clustering strategies support a dual processing model of verbal fluency.     

儿童、中青年及老年人心理旋转能力的比较研究

采用12套不同视觉形状图形,探讨了儿童(7—9岁,均龄8岁)、中青年(23—47岁,均龄31．3岁)及老年人(61—79岁,均龄65．6岁)的心理旋转能力。结果表明不同年龄段被试的心理旋转能力存在明显差异。无论是对图形方位匹配判断的准确性还是完成判断任务的速度,中青年组被试的成绩均明显优于其他两组被试。儿童组被试在完成判断的速度上明显优于老年组,但在准确性方面两者不存在明显差异。各个年龄组的成绩均不存在性别差异。     

Evidence that a factor besides progesterone, prolactin, or plasma-estradiol-binding protein inhibits estrogen-induced sexual receptivity in pregnant rats.

Daily administration of estradiol benzoate stimulated significantly less lordotic behavior in rats during the second half of pregnancy than in ovariectomized females that received subcutaneous progesterone implants, pituitary grafts that raised plasma prolactin, or both treatments combined. Following an initial facilitation of receptivity, females with progesterone implants showed only moderate reductions in lordosis quotients over 3 test days. The capacity of plasma from pregnant rats to bind estradiol was found to increase significantly during the second half of pregnancy. However, daily administration to pregnant rats of a synthetic estrogen, R 2858, which is not bound by plasma protein, was no more effective than estradiol benzoate in stimulating receptive behavior. Administration of estradiol benzoate also stimulated significantly lower levels of sexual behavior in pregnant females than in females in which pseudopregnancy had been prolonged by previous hysterectomy or induction of uterine decidualization. These findings suggest that some endocrine factor other than progesterone, prolactin, or estradiol-binding protein is primarily responsible for the potent suppression of behavioral responsiveness to estrogen which occurs in pregnant rats. It is suggested that 5 alpha-reduced androgens may cause these behavioral effects.     

Political Graphology

The interrelationship of digit span and word span was studied in a group of 112 females, 17-81 years of age. When the subjects were assigned to groups of 38 young ([Xbar] = 25.6 years), 39 middle-aged ([Xbar] = 53.2 years), and 35 old ([Xbar] = 73.3 years), the correlation between the two types of span was larger in the old than in the young, reflecting a predicted greater degree of homogeneity of functioning. When spans were scored without consideration for exact order of recall, this finding no longer held, as was the case with a capacity decrement in digit span with the aged, thus reflecting the importance of the organizational factor in senescent memory ability.     

Children's perceptions of and beliefs about facial maturity

The author studied children's and young adult's perceptions of facial age and beliefs about the sociability, cognitive ability, and physical fitness of adult faces. From pairs of photographs of adult faces, participants (4-6 years old, 8-10 years old, 13-16 years old, and 19-23 years old) selected the one face that appeared younger, older, better at remembering, smarter, more caring, friendlier, healthier, or stronger. Pairings consisted of faces at different adult age levels (young adults, middle-age adults, older adults, and very old adults.) Older participants were more sensitive to age differences in older faces and to faces more proximal in age. Children and adolescents believed that very old adult faces appeared to be less cognitively able than middle-aged faces (for children) and young adult faces (for adolescents). Very old male faces were judged to be less sociable. Old and very old faces were judged to be less physically fit than young and middle-aged faces. Significant positive correlation coefficients were found between the youngest children's abilities to discriminate between the adult faces of proximal age and youthful biases when selecting faces appearing to be more sociable and cognitively able. The results are discussed with respect to the development of facial information-processing skills and how those skills may be associated with the development of and changes in beliefs about older adults.     

Stability and change in adult intelligence: 2. Simultaneous analysis of longitudinal means and covariance structures

We analyzed data on psychometric intelligence from the Seattle Longitudinal Study, simultaneously estimating longitudinal factors, their covariance structure, and their mean levels. Data on five Thurstone Primary Mental Abilities subtests were available for 412 adults, ages 22-70 at first test, who were tested three times at 7-year intervals. A previous longitudinal factor analysis had shown high stability of individual differences (covariance stability) in general intelligence for three adult age groups. We extended that model to estimate factor means. All three age groups showed high levels of covariance stability, but differed sharply in their mean profiles. The young group showed increasing levels of general intelligence, the middle-aged group had stable levels of intelligence, and the old group showed salient, approximately linear, decline. The patterns of stability in middle-age, followed by mean decline and high covariance stability in old age, suggest a normative developmental transition from a stability pattern to a decline pattern of general intelligence, with the inflection point occurring somewhere around age 60.     

Global increase in response latencies by early middle age: complexity effects in individual performances

Ten young women (age 20 to 22 years) and 10 middle-aged women (age 36 to 44 years) served as subjects in choice reaction time, letter classification, and abstract matching-to-sample tasks. In each of seven conditions, the older group responded more slowly than the younger group. Age differences showed a complexity effect. That is, differences between the latencies of young and old subjects increased as the latency of the young subjects increased. Both linear and power functions accurately described the relation between the latencies of the middle-aged and young adult groups. This was true not only for the relation between average latencies but also for the relation between corresponding quartiles of latency distributions. Similar results were observed at the individual level: All middle-aged subjects showed complexity effects, and, for each middle-aged subject, the relation between her latencies and those of the average young adult was well described by linear and power functions. These findings indicate that age-related slowing is apparent by age 40, and that complexity effects are observable in individual performances. This slowing is global and not specific to particular tasks, as indicated by the fact that the latencies of older adults can be predicted directly from those of younger adults without regard to the nature of the task.     

Adult age and gender differences in perceptions of facial attractiveness: beauty is in the eye of the older beholder

The authors examined ratings of facial attractiveness, rankings of faces and reasons given by young, middle-aged, and older men and women for young, middle-aged, and older male and female face attractiveness. No support for predictions derived from similarity, interest, and cohort hypotheses was obtained. In support of the expertise hypothesis, young and middle-aged adults rated younger faces as more attractive than old faces, whereas older adults rated all aged faces equally. In support of the crone hypothesis, older female faces were rated the lowest of all faces. Theoretical implications and real-world applications are discussed.     

Adult Age and Gender Differences in Perceptions of Facial Attractiveness: Beauty is in the Eye of the Older Beholder

The authors examined ratings of facial attractiveness, rankings of faces, and reasons given by young, middle-aged, and older men and women for young, middle-aged, and older male and female face attractiveness. No support for predictions derived from similarity, interest, and cohort hypotheses was obtained. In support of the expertise hypothesis, young and middle-aged adults rated younger faces as more attractive than old faces, whereas older adults rated all aged faces equally. In support of the crone hypothesis, older female faces were rated the lowest of all faces. Theoretical implications and real-world applications are discussed.