Influence of home-cage lighting conditions on shock-induced fighting

A series of experiments was conducted to assess the influence of home-cage lighting conditions on shock-induced aggression in rats. The first two experiments tested rats six times within 24 hr and demonstrated that subjects maintained on a light/dark (LD) cycle fought more than rats maintained on a 24-hr light schedule (LL). In addition, a periodic trend could be identified in the data of the LD groups but not in the data of the LL groups. The second two experiments assessed the effects of castration on this lighting effect. Castration of adults did not influence the lighting effects, but castration of weanling rats eliminated the group difference between LL and LD groups. However, the LD rats castrated at weaning did show the periodic trend characteristic of all of the LD groups tested within 24 hr. Two additional experiments assessed the effects of time of testing in between-subjects designs. Time of testing was a significant variable in the LD groups but unimportant in the LL groups. A final experiment demonstrated that the difference between the LD and LL groups does not emerge in a daily testing procedure.     

Effect of vomeronasal organ removal from male mice on their preference for and neural Fos responses to female urinary odors.

Four experiments were conducted to determine whether vomeronasal organ (VNO) inputs in male mice mediate the rewarding properties of estrous female urinary odors. Sexually naive male mice with either an intact (VNOi) or lesioned (VNOx) VNO preferred to investigate female urine over water in Y-maze tests. Subsequently, VNOi males ran significantly more quickly and remained in nasal contact longer with estrous female urine than with male urine, whereas VNOx males investigated these odors equally. In home-cage habituation-dishabituation tests, VNOi males also investigated female urine significantly longer than did VNOx males, although both groups investigated female urine longer than other non-body odors. Finally, female urinary odors induced Fos in the nucleus accumbens core of VNOi males but not of VNOx males. Our results suggest that female urinary odors retain some incentive value in VNOx males. However, once direct nasal contact is made with female urine, VNO inputs further activate forebrain mechanisms that amplify the reward salience of this stimulus for the male mouse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responses of male Mongolian gerbils to male gerbil odors.

Offered adult male Mongolian gerbils (Meriones unguiculatus). the opportunity to enter and investigate several combinations of male gerbil-inhabited and uninhabited areas in a 2-choice preference apparatus. Responses of 12 normal, 10 bulbectomized, 10 enucleated, and 9 castrated Ss indicate that: (a) males prefer to investigate areas containing self-generated or conspecific-generated biological odors over areas containing no gerbil odors; (b) although entry and investigation time scores probably reflect different aspects of orientation to biological odors, both measures suggest that the complex of odors generated by males is attractive to male conspecifics; (c) the odors mediating preferences are dependent primarily but not exclusively on testicular androgen; and (d) preference for normal conspecific odors is not dependent on circulating testicular androgen in the responding S. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analgesic responses of male mice exposed to the odors of parasitized females: Effects of male sexual experience and infection status.

The present study shows that parasites influence both the responses of males to infected females and the responses of male hosts to females. Male mice exposed for 30 min to the odors of females infected with the nematode parasite Heligmosomoides polygyrus displayed a naloxone-sensitive, opioid-mediated analgesia, whereas males exposed for 1 min showed a shorter duration and lower amplitude naloxone-insensitive "nonopioid" analgesia that involved serotoninergic (5-HT) and excitatory amino acid (N-methyl-D-aspartate [NMDA] receptor) systems. The male mice distinguished between the odors of infected and physically stressed females, displaying greater analgesia after exposure to the odors of infected than stressed females. The analgesic responses to the odors of infected females were also affected by the males' prior sexual experience; sexually experienced males exhibited significantly greater analgesia than sexually naive males. In contrast, male mice infected with H. polygyrus failed to show a nonopioid analgesia after exposure to the odors of infected females and displayed a markedly lower level of opioid analgesia than uninfected mice. These results show that male mice can discriminate between the odors of parasitized and nonparasitized females… (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Steady-state methadone effect on generalized arousal in male and female mice.

Methadone is widely used in treatment of short-acting opiate addiction. The on-off effects of opioids have been documented to have profound differences from steady-state opioids. The authors hypothesize that opioids play important roles in either generalized arousal (GA) or aversive state of arousal during opioid withdrawal. Both male and female C57BL6 mice received steady-state methadone (SSM) through osmotic pumps at 10 or 20 mg/kg/day, and GA was measured in voluntary motor activity, sensory responsivity, and contextual fear conditioning. SSM did not have any effect on those GA behaviors in either sex. Females had higher activity and less fear conditioning than males. The effects of SSM on stress-responsive orexin gene expression in the lateral hypothalamus (LH) and medial hypothalamus (MH, including perifornical and dorsomedial areas) were measured after the behavioral tests. Females showed significantly lower basal LH (but not MH) orexin mRNA levels than males. A panel of GA stressors increased LH orexin mRNA levels in females only; these increases were blunted by SSM at 20 mg/kg. In summary, SSM had no effect on GA behaviors. In females, SSM blunted the GA stress-induced LH orexin gene expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrasonic vocalizations by male house mice (Mus musculus) to novel odors: Roles of infant and adult experience.

Conducted 2 experiments to examine 70-kHz ultrasonic courtship vocalizations by adult male mice to novel odors following exposure to these odors in infancy and/or adulthood. Exp I, with 72 males, demonstrated that adult males normally do not vocalize to the urine of female rats but would if adult female mice odorized with female rat urine were repeatedly encountered postpubertally. On the other hand, encountering their own mother odorized with female rat urine from birth until weaning did not promote vocalizations to the urine of female rats. Exp II, with 100 males, examined vocalizations to the urine of female mice whose urinary odor was altered by the ingestion of fenugreek, a spice. Greater amounts of vocalization again were seen by males that as adults encountered females that had ingested fenugreek. Again, experience with the novel odor during infancy was not associated with elevated vocalizations during adulthood either to fenugreek-altered urine or to the fenugreek odor itself. Vocalizations to 2 different novel odors occurred only after an adult male had encountered an adult female odorized with the novel odor. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Odor preference and urine-marking scales in male and female rats: Effects of gonadectomy and sexual experience on responses to conspecific odors.

Investigation and urine-marking responses of 112 male and female Long-Evans rats toward conspecific urine odors were recorded in pair-wise comparison tests. Each of 16 S groups was given 15 preference tests, 1 for each of the possible pairs of 5 urine odors and a no-odor control (N). The urine sources were own group (G), intact male (M), castrated male (Mc), ovariectomized female (Fo), and estrous females (F). Results were scaled by using a technique based on L. L. Thurstone's (1927) law of comparative judgment. Intact males with sexual experience ordered their odor preferences N?     

Reaction of male Mongolian gerbils to odors in a social situation.

Examined the possibility that odor from substances rubbed on the back of young stimulus animals will influence the social behavior of male gerbils. 30 adult Ss were tested for 4 5-min sessions with young male conspecifics that had water, perfume, urine, or ventral gland sebum rubbed on their back. Ss showed significantly longer investigation duration and higher approach frequencies toward Ss treated with urine or sebum. Results demonstrate that gerbils are attracted to relevant odors in a social situation. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Odor preferences of female Peromyscus maniculatus bairdi for male mouse odors of P. m. bairdi and P. leucopus noveboracensis as a function of estrous state.

Tested 20 sexually naive mature P. m. bairdi female mice for male mouse (P. m. bairdi and P. l. noveboracensis) odor preferences during natural estrous and diestrous conditions in a 2-choice Plexiglas olfactorium. The homospecific odor side was chosen 76% of the time by estrous Ss and 43% of the time by diestrous Ss. Only the estrous group differed significantly from the expected 50:50 distribution. High intratest reliability coefficients suggested stable modes of responding within test sessions. These findings suggest female P. m. bairdi reactions to male mouse odors are influenced by gonadal state, and that olfaction conceivably plays a role in sexual isolation between these species. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Different patterns of biting attack employed by lactating female mice (Mus domesticus) in encounters with male and female conspecific intruders.

Attacks by resident lactating female mice were examined in a variety of situations. Relatively few attack bites to vulnerable body regions were seen when pairs of unfamiliar lactating females fought, establishing social status prior to communal nesting. Sexually naive male and female intruders were equally prone to attack by lactating females, but patterns of bite attack generated by them were very different; males received the more damaging attacks. More signs of "fear" were seen in the lactating females' responses to male rather than female intruders. Varied motivations may underlie attacks by lactating females directed to conspecific intruders. Defensive patterns of biting by lactating females are more consistently directed towards males, intruders that are more likely to harm or destroy the litter. Although attacks by females rarely thwarted infanticide by male intruders, the behavior may acutely protect parental investment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responses of male hamsters to odors of females in different reproductive states.

Six experiments investigated the responses of male hamsters to the odors of estrous, diestrous, pregnant, and lactating hamsters. Scent-marking by males in the soiled cages of females was less frequent when the females were estrous (Day 1 of the cycle) than when females were on Days 2, 3, or 4. Sexually experienced males preferred the odors of bedding material from the cages of estrous Ss over odors of bedding of diestrous Ss. Both of these effects were eliminated by surgically removing the vagina and thereby eliminating vaginal secretions. The quantity of vaginal secretions deposited in the vicinity of the nest may be responsible for the observed effects. In contrast, neither males with sexual experience nor males with both sexual and nonsexual experience with females demonstrated preferences for the odors of the estrous or diestrous Ss themselves. Males were, however, more attracted to the odors emanating directly from estrous Ss than to the odors of pregnant or lactating Ss. For hamsters the important sexual message may be not "estrous" vs "diestrous" but rather may be "will soon be estrous" (i.e., cycling) vs "not soon estrous" (i.e., pregnant, lactating, or acyclic). (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of dominance-submission relationships in shock-induced fighting of mice.

Studied 96 male DBA/2J mice. Ss were caged in pairs until dominance-submission hierarchies formed. The effects of social roles, fight training, and unfamiliarity on shock-induced biting attack and upright postures were examined under 4 levels of shock intensity. Biting attack was almost exclusively the behavior of dominant mice, and it predominated for all groups except submissive-submissive pairs, which responded to shock almost entirely with the upright posture. Fight training increased the amount of fighting response to shock. Unfamiliarity increased fighting at low shock levels and depressed fighting at high shock levels. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Counseling skills used by Black and White male and female counselors.

A videotape of culturally varied client vignettes was viewed by Black and White males and females, all of whom had at least some counselor-related training. Participants responded in writing to the question, "What would you say to this person?" The data were coded according to a counseling skills scoring system. Black males and females tended to use the more active expression skills (e.g., directions, expressions of content, and interpretations) with greater frequency than did Whites. White males and females tended to use a high percentage of attending skills. In particular, White females used reflections of feeling frequently, and White males tended to respond with questions. While race appeared as a source of strong effect, one of the major implications of this study was the relative absence of significant sex differences. Discussion focuses on cultural variation in counseling styles, implications for training, and promotion of diversity among professionals. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Body-figure preferences in male and female adolescents.

Previous research has examined body dissatisfaction and pressures toward thinness among college-age and adult women, demonstrating greater dissatisfaction among women than men. Little is known about when such sex differences arise. The present study replicated the procedure used by Fallon and Rozin (1985) to assess body-size preferences in a sample of 288 female and 283 male adolescents aged 10.5 to 15 years. Both sexes revealed a small degree of body-figure dissatisfaction relative to their chosen ideal, but neither sex rated their own figure as significantly different from the size considered most attractive to the opposite sex. Both male and female adolescents held distorted perceptions of opposite-sex preferences. Girls showed a bias toward thinness; boys revealed a bias toward larger figures. The latter bias was associated with pubertal development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competitive behavior in male, female, and pseudohermaphroditic female dogs.

Tested 36 male, spayed female, and pseudohermaphroditic female dogs in pairs for competition over a large bone. Pseudohermaphrodites had been exposed to testosterone propionate before and immediately after birth. In equal opportunity (EO) tests, both members of a pair had equal chance to seize the bone. Each EO test was followed by an established possession (EP) test. During an EP test, the loser of the preceding EO test was given possession of the bone before the former winner was returned to the test arena. Every S was tested against all other members of its own and the other groups. Males won 78 of 100 EO tests against normal females but only 61 of 100 against pseudohermaphrodites. Pseudohermaphrodites won 70 of 100 EO tests against normal females. When either normal or pseudohermaphroditic females were given possession of the bone in EP tests they were equally ineffective in defense against male challengers, losing 75 and 71% of their tests, respectively. Both types of females were more successful in defending possession during EP tests against each other. When normal and pseudohermaphroditic females were treated with testosterone, their performance in competition tests was not altered. Androgenic stimulation before and immediately after birth permanently modified the social behavior of pseudohermaphrodites as well as the behavior of males and normal females toward experimental Ss. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vocational interests of male and female social workers.

For a sample of 496 male social workers, a key was constructed for the Strong VIB that differentiated them from a Men-in-General group with only 16% overlap. A key for female social workers (N = 464) differentiated them from Women-in-General with only 29% overlap. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Research productivity and impact of male and female psychologists.

Investigated whether the marked underrepresentation of females in lists of highly cited psychologists reflected differences in the quality or the quantity of research produced by males and females. Citation counts were established for 396 papers reporting dissertation research published by male and female psychologists in 14 journals between 1967 and 1972. Females attracted as many citations as males for dissertation research over the 6 yrs following publication. Although females had by 1978 published significantly fewer papers than males, there was no difference between sexes in the number of citations gained/published paper. However, more males than females were prolific researchers with heavy outputs of highly cited papers. Sex differences in productivity, impact, and recognition are discussed in the context of factors that facilitate or hinder research achievement. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personal adjustment of male and female homosexuals and heterosexuals.

Compared the personal adjustment and psychological well-being of 127 male and 84 female homosexuals with 123 male and 94 female heterosexuals. Ss were matched for sex, age, and education. Homosexuals did not differ in important ways from heterosexuals in defensiveness, personal adjustment, or self-confidence as measured by the adjective check list; or in self-evaluation as measured by a semantic differential. Male homosexuals were less defensive and less self-confident (p     

Kindling-induced emotional behavior in male and female rats.

Modeling fear in animals is a critical approach for identifying the neural mechanisms involved in human disorders such as generalized anxiety and panic. Amygdala kindling has proven useful in this regard because it produces dramatic increases in fearful behavior. The purpose of this experiment was to compare the behavioral effects of kindling in male and female rats. Compared with the sham-stimulated rats, the kindled male and female rats showed similar increases in fearful behavior, with some sex differences in fear-related open-field activity. They also showed decreased immobility in the forced-swim test and increased sucrose consumption. These results suggest that kindling-induced fear is generally similar in male and female rats and that kindling does not appear to induce depression-like behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)