Effects of early exposure to mating on adult sexual behavior in male mice varying in their genetic disposition for aggressive behavior

This study examined whether the sexual behavior of adult male mice is influenced by exposure in early postnatal life to brief episodes of mating. Another focus of interest was the interplay between a genetic disposition for aggressive behavior and the early exposure experiences. The subjects used in the study were male mice of the fiftysixth generation of selection for high (Turku aggressive, TA) and low (Turku non-aggressive, TNA) levels of aggressiveness. Moderately aggressive males of the parental strain (normal, N) were also used. Subjects of each strain were exposed from 21 to 32 days of age to mating mice behind a wire mesh screen. Control subjects were placed in a comparable enclosure, but were exposed to nothing. The results showed that male mice exposed to mating early in life showed a higher rate of activities in the sexuality tests, including aggressive responses. A genetic potential for aggressive behavior was related to a higher degree of sexual activity, and the early exposures optimized the hereditary attributes. The relation between sexual and aggressive behavior is discussed. © 1994 Wiley-Liss, Inc.     

Effects of isolation during development on reactivity and home-cage agonistic behavior in rats

This experiment was designed to determine whether isolation during two developmental periods would contribute to differences in home-cage agonistic behavior and whether altered reactivity was a mediating variable. While early isolation (16–41 days) was shown to have a significant and sustained impact on agonistic behavior, isolation during a later developmental period (41–68 days) did not result in altered occurrences of agonistic behavior. While isolation did result in increased reactivity to both footshock and dorsal tactile stimuli, the pattern of these data suggested that hyperreactivity to tactile stimulation was not a satisfactory account of the increased agonistic behavior of rats raised in isolation.     

Effects of early seizures on later behavior and epileptogenicity

Both clinical and laboratory studies demonstrate that seizures early in life can result in permanent behavioral abnormalities and enhance epileptogenicity. Understanding the critical periods of vulnerability of the developing nervous system to seizure-induced changes may provide insights into parallel or divergent processes in the development of autism. In experimental rodent models, the consequences of seizures are dependent on age, etiology, seizure duration, and frequency. Recurring seizures in immature rats result in long-term adverse effects on learning and memory. These behavioral changes are paralleled by changes in brain connectivity, changes in excitatory neurotransmitter receptor distribution, and decreased neurogenesis. These changes occur in the absence of cell loss. Although impaired cognitive function and brain changes have been well-documented following early-onset seizures, the mechanisms of seizure-induced dysfunction remain unclear.     

Effects of medial preoptic-anterior hypothalamic lesions on development of sociosexual behavior in dogs

Bilateral medial preoptic-anterior hypothalamic lesions in adult male dogs eliminate or impair copulatory behavior and reduce urine-marking responses but do not affect aggressive behavior. The present study examined the emergence of the adult forms of these same male sociosexual behavioral patterns when the lesions are made prior to puberty. The subjects were allowed to interact with male peers during development. Animals with lesions had reduced frequence of juvenile mounting and an almost total absence of male copulatory activity in adulthood. Urine-marking and aggressive behavior in the juvenile and adult periods were not affected by the lesions. The findings reveal a sparing of function with regard to urine-marking but not sexual behavior.     

Ontogeny of aggressive-sexual behavior between males in lines of Japanese quail (Coturnix coturnix japonica) selected for male mating frequency

Japanese quail from lines bidirectionally selected for high and low male mating frequency and from the random-bred base population were observed in an ontogenetic study of aggressive-sexual behavior. Quail were reared in sex-intermingled flocks until 28 days of age at which time half of the males from each line were housed as all-male flocks and half were transferred to individual cages. At 41 days of age, individually caged males exhibited mounting behavior to win encounters with other males. By 45 days, males from the high and control lines exhibited significantly more aggressive-sexual behavior than those from the low lines. Line x Rearing Experience interactions for mounting behavior at 45 and 56 days of age were due to the individually caged high- and control-line males' winning encounters by mounts; those maintained in flocks rarely mounted. Although some low-line males won encounters by mounts, occurrence of this behavior was infrequent. Males maintained in flocks were placed in individual cages at 57 days of age. When these males were compared with those housed in individual cages from 28 days of age, at 84 days of age and older, the Line x Rearing Experience interaction observed previously disappeared, and only differences among genetic lines were evident. Genetic and rearing experience effects are discussed as influencing agonistic and sexual behaviors.     

Coital behaviors, attitudes, and knowledge of students who experience early coitus

The purpose of this study was to investigate coital behavior, contraceptive practices, and attitudinal and knowledge differences between "early coital initiators" (subjects having initial coitus at 16 years or younger) and "late coital initiators" (subjects having initial coitus from 17 to 20 years of age). Data were compiled from the results of a questionnaire administered to 929 students enrolled in personal health courses at 14 colleges and universities. The sample used for analysis included only the never-married coitally experienced males and females aged 20 and older (N = 396). The results suggested that late coital initiators: were more effective contraceptors during initial coitus; had more committed relationships with their initial sex partners; engaged in more discussion about and planning for contraceptive use; and used more authoritative and reliable sources for contraceptive information than their younger counterparts. Both groups scored very low on basic knowledge questions concerning fertility, contraception, and sexually transmitted diseases. These results mandate greater public concern and involvement to delay early coital experiences and prevent unprotected sexual intercourse.     

Intergenerational transmission of violent behavior in adolescent males

The purpose of this study was to examine the intergenerational influence of experiencing parental violence on the expression of violent behavior in adolescent males and to attempt to assess the importance of psychological mechanisms in this transmission. Sixty-five consecutive male admissions to a Young Offenders Unit and 25 male high school boys were administered the Minnesota Multiphasic Personality Inventory (MMPI), the Culture-Free-Self-Esteem Inventory, an intelligence test, and a violence questionnaire. Violent behavior in adolescence was found to be associated with experiencing paternal violence. This transmission was also found to be associated with higher levels of psychotic symptomatology. Violent behavior in adolescence was not found to be associated with maternal violence experienced or parental violence witnessed or with low self-esteem, externalizing defences, or internalizing defences. © 1992 Wiley-Liss, Inc.     

Self-stimulation and mating behavior in the male rat

Abstract.— A presumed relationship between selfstimulation of the brain and sexual behavior was studied in two experiments. In the first experiment the male rat was allowed self-stimulation during a period of 5 minutes and thereafter transferred to a mating cage with a female. No effects of the self-stimulation were recorded in the mating behavior. In the second experiment the male was allowed one intromission and thereafter presented with a lever for self-stimulation, still having access to the female. The sexual responses were completely inhibited, and selfstimulation at normal rate resumed. It was concluded that there is no necessary link between self-stimulation of the brain and sexual behavior.