摘要:

AbstractPersistence of social attention by male and female laboratory rats was examined following exposure to novel conspecifics. In Experiment I we compared performance of castrate females treated with a 10‐day regimen of testosterone propionate to that of intact males and castrate female controls. Testosterone significantly prolonged mean social investigation time. Castrate females treated with a relatively high dosage of testosterone failed to differ from intact males. In Experiment II we compared neonatally andorganized female castrates with castrate male and castrate female controls. Postnatal exposure to testosterone increased sensitivity of females to exogenous testosterone in maturity as measured by persistence of social investigation. In Experiment III we compared investigation time of intact and castrated males and females at 10‐day intervals from 40 to 80 days of age. Intact males investigated novel conspecifics significantly longer than other groups, with longest investigation times at 60 and 70 days of age. In Experiment IV we compared investigation times of 30‐day, 60‐day, and 200‐day‐old males. Sixty‐day‐old males investigated significantly longer than 30‐day‐old or 200‐day‐old groups, which failed to differ from each other. The combined results demonstrate a gender and aggregated effect of testosterone on persistence

ISSN:0012-1630    

DOI:10.1002/dev.420150102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractGroups of 20–34 C577BL/6J mice, aged 75, 225, 375, and 525 days, learned a brightness discrimination for water. The error scores of the 75‐ and 525‐day groups were almost identical, and both made significantly more errors than the 225‐day‐old mice. Both immature and older mice appear to be deficient in learning ability compared to you

ISSN:0012-1630    

DOI:10.1002/dev.420150103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractFifteen male C57BL/6J mice, exposed to an enriched environment from age 600 to 750 days, were compared with 15 matched controls on 4 learning problems and an activity test. The enriched mice were significantly superior on an incidental learning and a food‐seeking task, but did not differ significantly from controls on a brightness discrimination task, the Lashley III maze and an activity test. The relative abundance of high and low ribonucleic acid‐containing cerebrocortical cells differed significantly between groups; the enriched mice had more cells with very high levels of RNA. The mammalian brain appears to remain responsive to environmental enrichment well into advanced

ISSN:0012-1630    

DOI:10.1002/dev.420150104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractTwo types of motor asymmetry, postural asymmetry and lateral head turning, were assessed in 3 groups of preterm infants, one of which had experienced respiratory distress syndrome (RDS) in the postnatal period. Results reveal that maintenance of a right postural asymmetry is present as early as 34 weeks conceptional age and is not disrupted by postnatal illness. Lateral head turning after midline placement was evident as early as 36 weeks conceptional age but was disrupted by physiologic condition. Infants who had experienced RDS had poor muscle tonus and did not assume the head right position even at 39 weeks conceptional age. These data argue that lateral responding may be affected by illness and that studies of preterm populations must evaluate postnatal medical condition when assessing both the short‐ and long‐term outcomes of lateral asymmetr

ISSN:0012-1630    

DOI:10.1002/dev.420150105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThree experiments are reported on the feeding behavior of suckling rabbits (“kittens”). In the 1st the latency with which the kittens attached to the nipple, and then left the nipple, was determined. Attachment was very rapid and wholly reliable: on the 80 tests the nipple was seized in every case in under 9 sec, and on 67 of these in less than 3 sec. The kittens also invariably left the nipple within the next minute. If the kittens were 5 or 10 days old speed of attachment was unaffected by the presence or absence of saliva on the nipple, but 15‐ and 20‐day‐old kittens seized the sucked nipples more rapidly than the unsucked nipples. In a 2nd experiment with 12‐day‐old kittens, washing the nipple with solvents did not affect speed of attachment; nor did saliva. The results show that suckling rabbits, in contrast to rat pups, are not heavily dependent on saliva cues. In the 3rd experiment both attachment latency and milk intake were shown to be affected by an internal stimulus, a gastric load of .9% saline, 5 g/25 g body weight: attachment latency was significantly increased and milk intake r

ISSN:0012-1630    

DOI:10.1002/dev.420150106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe hoarding behavior of 4 litters of Golden hamster pups (n= 3) was observed every 2nd day between the ages of 13 and 47 days (2 litters) or 13 and 55 days (2 litters). Each litter lived with the mother until Day 30; then the pups were put in social isolation. Immature forms of pouch filling and emptying, which were not integrated into coherent behavior sequences, appeared from the beginning of the observation period. Coordinated hoarding trips were shown from Day 21 onwards, once the motor patterns of inserting and extracting food had gained their definitive form. The development of hoarding was correlated with the animal's body weight and therefore with maturational factors. Mature hoarding behavior was greatly enhanced by the subject's separation from its family unit.

ISSN:0012-1630    

DOI:10.1002/dev.420150107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe unrestricted adult social and nonsocial behavior of albino rats isolated from 21 to 70 days of age was compared with the behavior of rats receiving normal social experience. Isolated animals exhibited aberrant self‐manipulative behaviors during the period of isolation, and both isolate‐reared males and females were more aggressive than their group‐reared counterparts. The hypothesis that females are buffered against the effects of social isolation received little support. Numerous gender differences and differences in the gender of the objects of social response were found for both isolate‐ and group‐reared rats. Gender and Rearing Conditions were relatively independent influences on behavior with few Gender X Treatment interactions reaching sig

ISSN:0012-1630    

DOI:10.1002/dev.420150108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractWebs ofAraneusdiadematus Cl. were obtained under drugged (dextroamphetamine) and control conditions at three age‐periods in the development of the spider from juvenility to sexual maturity. Although certain features of construction are affected in all periods and some exhibit differential effects with age, it was not possible to separate the latter from changes in body mass between period

ISSN:0012-1630    

DOI:10.1002/dev.420150109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractZebra fish and pearl danios were either cross‐reared or raised with conspecifics and tested as adults for species preference over 4 days. Subjects were then placed with conspecifics by group for 30 days and retested over 2 days. Initial testing showed less preference (species identification) for conspecifics by cross‐reared subjects and less conspecific preference by pearls than zebras. At retesting pearls showed a great increase in preference for conspecifics whereas zebras showed little cha

ISSN:0012-1630    

DOI:10.1002/dev.420150110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractEarlier experiments have shown that many of the effects of early social isolation in the rat may be due to deprivation of social play. The isolated ferret, like the isolated rat, is hyperactive; further‐more, its hyperactivity appears to be related to deprivation of social play. However, the relationship between object investigation and social rearing is more complex in the ferret than it is in the ra

ISSN:0012-1630    

DOI:10.1002/dev.420150111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY