Scopolamine interactions with D1 and D2 antagonists on radial-arm maze performance in rats

Recent evidence indicates that acetylcholine and dopamine play complementary roles in cognitive as well as motor functions. In our previous study, the dopamine receptor blocker, haloperidol, was found to attenuate the radial-arm maze choice accuracy deficit caused by the muscarinic acetylcholine receptor blocker, scopolamine. Haloperidol has activity in blocking both D1 and D2 dopamine receptor subtypes. The current study was conducted to determine whether this dopamine-acetylcholine interaction specifically involved D1 or D2 dopamine receptors. The D1 antagonist, SCH 23390, and the D2 antagonist, raclopride, were administered with a dose of scopolamine which caused choice accuracy deficits in the radial-arm maze. The scopolamine-induced deficit was reversed by SCH 23390, the D1 antagonist, indicating that D1 blockade alone is sufficient to reverse the amnestic effects of muscarinic blockade. There was no indication in this study that the D2 blocker, raclopride, had a similar effect. However, this does not mean that such an effect may not be present at other doses of raclopride or with other D2 antagonists. The present finding that D1 blockade counteracts scopolamine-induced cognitive dysfunction not only furthers the understanding of dopamine-acetylcholine relationships in cognitive function, it also suggests a promising direction for the development of treatments for cognitive dysfunction due to cholinergic loss.     

Some tests of the interactive-activation model for word identification

Summary The interactive-activation model postulates (a) that activation at the letter level leads automatically to activation at the word level, (b) that the word-superiority effect reflects reactivation of letters by the word they spell, and (c) that subjects identify words on the basis of information obtained from separate letter-position channels. In the first two experiments, we showed words in upper, lower, or mixed case: the word-superiority effect was reduced when words were presented in mixed-case letters, presumably because extra-letter information is lost with mixed-case presentation; i.e., postulate (c) is wrong. The third experiment showed that when the letters of a word are rotated 180° subjects can identify the letters without producing a word-superiority effect; i.e., one of postulates (a) and (b) is wrong. In Experiments 4 and 5, we trained subjects to name words presented in inverted letters; training was more effective when subjects could exploit bigram information in addition to letter-channel information; i.e., reading inverted text is based on extra-letter-feature information, not on a general skill in rotating letters. Taken together, our data deny three of the interactive-activation model's major postulates. We offer some suggestions for future versions of the model. Electronic mail: Userid: MEWHORTD; Nodeid: QUCDN; Domain: BITNET     

The relation of gender-role orientation to sexual experience among college students

This study examined the relations of gender and three aspects of gender roles — self concept, behavior, and sexual attitudes — to three aspects of sexual behavior — sexual experience, reasons for intercourse, and contraceptive use. Gender was strongly related to all three aspects of sexual behavior. For both men and women, sex role behaviors were related to sexual experience and to reasons for intercourse, but not to contraceptive use, and sex role self-concept was unrelated to any of the aspects of sexual behavior. The results indicate that sexual behavior is influenced both by societal gender role norms and by individual differences in the acceptance of those norms.     

A developmental-genetic analysis of aggressive behavior in mice (Mus musculus): III. Behavioral mediation by heightened reactivity or immobility?

This research was designed to investigate development and behavioral mediation in lines of ICR mice that have been selectively bred for aggressive behavior. General behavioral reactivity and behavioral immobility have been implicated as potential mediators by prior analyses of preattack interactions. To evaluate the separate roles of these dispositions, the emergence of attacks in genetically selected lines was tracked for 11 years by three levels of analysis: over successive generations, over development, and over dyadic interactions. Convergent outcomes were observed in all three levels with respect to two findings: (a) Robust line differences were obtained in attack behaviors, and (b) strong associations were found between line differences in attacks and line differences in behavioral immobility. Conversely, all three levels of analysis indicated a weak and inconsistent association between line differences in attacks and measures of social and nonsocial reactivity.     

Effect of the interintromission interval on lordotic response and attack latency in golden hamsters (Mesocricetus auratus)

After 12-15 ejaculatory series, each consisting of several short intromissions (2- to 3-s vaginal penetration) and an ejaculation, male golden hamsters adopt an altered copulatory pattern consisting of long intromissions (5- to 25-s penetration with intravaginal thrusting). Receptivity declines and the tendency for the female to attack the male increases at about the time of this shift in copulatory pattern. Because the mean interintromission interval (III) between short intromissions is about 8 s compared to 100 s between long intromissions, it is possible that females detect this difference and adjust their mating accordingly. When the III between short intromissions from a rested male was experimentally increased to 100 s by use of a halter and lead device, the duration of lordosis was significantly less than that displayed by females paired with control males (8-s III) and virtually the same as that displayed by females paired with males that produced only long intromissions. This suggests that the female uses the temporal patterning of intravaginal stimulation as one criterion for terminating mating with a particular male.     

Prophetic visions in 1988: A critical reappraisal

This paper reviews the research into a specific aspect of neardeath experiences (NDEs): the prophetic vision (PV). PVs are subjectively compelling flashforwards of planetary-wide cataclysms and eventual regeneration that sometimes occur during or in the immediate aftermath of an NDE. Previous research has shown that the most frequently mentioned year for the culmination of the geophysical calamities foreseen in PVs was 1988. I argue that PVs should be understood as manifestations of a collective prophetic impulse that historically tends to arise during periods of cultural crisis. PVs are thus expressions of the felt need for cultural renewal and therefore should not be taken literally as prognostic of drastic physical changes on Earth.     

Logical pragmatism and dialectical materialism: The beginning of dialogue

A philosophical movement, correctly called logical pragmatism, is growing up around the philosophy of W. V. O. Quine, Soviet scholars follow this development with clear and well-grounded understanding of the origins and tenets of the system. This essay continues the dialogue between contemporary Marxism-Leninism and logical pragmatism recommended by Soviet scholars.A Russian translation of this article is being published inFilosofskie nauki (Moscow).     

Attitudes toward older and younger adults: a meta-analysis

Attitudes toward the elderly have been examined in a number of empirical studies, yet the question of whether the elderly are viewed more negatively than younger persons has not been resolved. A meta-analysis of the literature was conducted to examine this question; results demonstrated that attitudes toward the elderly are more negative than attitudes toward younger people. However, smaller differences between the evaluations of elderly and younger targets were found when (a) the study used measures of personality traits (compared with measures of competence), (b) there were a larger number of dependent measures included in the effect size, (c) specific information was provided about the target person (compared with when a general target such as old person was used), and (d) a between-subjects design (compared with a within-subjects design) was used. These results support Lutsky's (1981) conclusion that age, in and of itself, seems to be less important in determining attitudes toward the elderly than other types of information. The methodological limitations within the literature and a need to consider multiple components of attitudes toward older individuals are discussed.