ISSN:0012-1630    

DOI:10.1002/dev.420020402

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

年代:1969

数据来源: WILEY

摘要:

AbstractThe experiments described examine the influence of early chronic treatment with amphetamine (AMPH) or chlorpromazine (CPZ) on the formation of adult dominance behavior in two genera of mice,i.e., Peromyscus maniculatus bairdiand a random bred, Swiss albino strain ofMus musculus. It was found that AMPH‐pretreated Swiss albinos were significantly more dominant than either CPZ‐pretreated or control animals. Early drug treatment had little effect on dominance behavior of adultbairdi. These results indicate that chronic administration of certain drugs to young animals is capable of producing a quantitative change in the formation of adult behavioral patterns. Moreover, the degree to which early drug treatment alters adult behavior is influenced by the genetic background of the organ

ISSN:0012-1630    

DOI:10.1002/dev.420020403

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

年代:1969

数据来源: WILEY

摘要:

AbstractTwo studies of motor response thresholds (RTs) to electricalstimulation at the wrist in newborns were done. Adult controls were employed. Strength‐duration curves for infant and adult RTs and adult sensory thresholds (STs) were plotted. RTs of infants are approximately 1.75 times higher than those for adults. Adult RTs are consistently 3 to 4 times higher than STs. Test‐retest reliabilities were satisfactory. RTs of half of the newborns were notably variable. No relationship between RT variability and stages of the neonatal wakefulness‐sleep cycle could be established, but RTs were significantly, although not markedly, higher during rapid‐eye‐movement (REM) episodes than during nREM. For evoked potential studies with newborns it has been decided to use as a stimulus a constant‐current square‐wave electrical pulse of 0.5 msec duration at RT duri

ISSN:0012-1630    

DOI:10.1002/dev.420020404

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

年代:1969

数据来源: WILEY

摘要:

AbstractFifteen rhesus monkeys with induced phenylketonuria (PKU) were compared with 12 controls in a 6‐sec DRL task that was preceded by continuously reinforced (CRF) training in half of each group and followed by reward magnitude variations. No differences were found in the acquisition of the CRF or DRL behavior in the subgroups having no prior training, but PKUs that were shifted from CRF to DRL conditions persisted in making incorrect short‐latency responses on the early trials of DRL sessions. This effect and a subsequent finding of inferior DRL performance by PKUs when reward magnitude was reduced were interpreted in terms of current frustration the

ISSN:0012-1630    

DOI:10.1002/dev.420020405

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

年代:1969

数据来源: WILEY

摘要:

AbstractIn Experiment I, rat litters that contained 3 or 9 pups were exposed to either silence, 55 db, or 90 db radio sounds during the preweaning period. The dependent variables were (a) measures of nest height and nest quality, (b) infant mortality, (c) weaning weights, and (d) activity and defecation on 3 open‐field trials. Small‐litter subjects (Ss) were heavier at weaning but their open‐field performance was virtually identical to that of large‐litter Ss. The 55‐db group was significantly more active on the 2nd and 3rd open‐field trials. In the 2nd experiment, litters of 3 and 9 pups were exposed to 55 db or 90 db radio stimulation throughout the preweaning period. Results similar to those of the first experiment were obtained. Both studies indicate that litter size variations do not influence subsequent emotional behavior, whereas the degree of auditory input during preweaning can have marked effects upon emotional

ISSN:0012-1630    

DOI:10.1002/dev.420020406

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

年代:1969

数据来源: WILEY

摘要:

AbstractThe behavioral and polygraphic characteristics of wakefulness and sleep were studied in 20 infant rats, 26 kittens, and 25 infant guinea pigs during their first month of postnatal life. In the infant guinea pig, the electrocorticographic (ECoG) patterns of sleep were similar to those of the adult, except for the absence of spindles during the first 3 weeks. In the rat and the cat, states of vigilance were not clearly differentiated in ECoG patterns during the first week; near the 8th day a fast, high amplitude ECoG appeared during paradoxical sleep (PS). The first signs of slow‐wave sleep (SWS) appeared at 11 to 13 days of age in the rat and at 15 to 21 days in the cat. The greater the immaturity of the animal at birth, the greater was the amount of time spent in PS in the perinatal period. In the rat, which was born the most immature, the decrease in the percent time of PS was very rapid: 70 % at birth, it decreased to 12% on the 30th day. In the cat the decrease was slower. In the guinea pig, despite its relative maturity, the percent time of PS at birth was 7%, approximately double that in the adult. The length of extrauterine life as well as the degree of immaturity at birth, played a role in the development of the sleep‐wakefulness cy

ISSN:0012-1630    

DOI:10.1002/dev.420020407

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

年代:1969

数据来源: WILEY

摘要:

AbstractBlood and tissue levels of phenylalanine and tyrosine progressively increase during he first two weeks of feeding a phenylalanine‐rich diet to weanling rats. During the same time, liver phenylalanine hydroxylase activity and brain serotonin progressively decline. Hepatic tryptophan hydroxylase activity drops quickly to a constant, low level. With the exception of tryptophan hydroxylase, all of these parameters return towards normal upon continuous treatment. The magnitude of change varies with the age of the animal at initiation of dietary treatment and arises because of Differences in effective dosage and metabolism as the animals mature. A single phenylalanine injection produces a transient elevation in tissue phenylalanine levels without appreciably affecting brain serotonin. Repeated phenylalanine injections produce more marked alterations in tissue phenylalanine and tyrosine levels, lower activity of tryptophan hydroxylase, and increase serum adrenocorticoids; phenylalanine hydroxylase activity and brain serotonin levels are only marginally affected. These changes seriously complicate interpretations of time‐consuming behavioral studies in experimental

ISSN:0012-1630    

DOI:10.1002/dev.420020408

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

年代:1969

数据来源: WILEY

摘要:

AbstractThe orienting response of hand and mother‐reared kittens who had been given daily doses of propylthiouracil during the first 50 days of life was tested at 60 days of age. Heart rate, respiration rate, and eye fixation on a visual stimulus were the measures used. A momentary light‐buzzer combination and a 30‐sec presentation of a rotating disc were the stimuli. There were no rearing or drug effects. Heart rate response was greater to the offset of the 30‐sec stimulus than to its onset. Respiration, the most sensitive measure, was speeded in the presence of a stimulus. Eye fixation, heart rate, and respiration rate curves during the 30‐sec stimulus were not

ISSN:0012-1630    

DOI:10.1002/dev.420020409

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

年代:1969

数据来源: WILEY

摘要:

AbstractThe development of behaviors during the first 50 days of life was observed in four squirrel monkeys who had been separated from their mothers shortly after birth. Behaviors observed included those related to nursing and maternal contact as well as sensory development, locomotion, and eating. Those behaviors closely related to maternal contact and nursing were particularly strong and persistent as compared to similar behaviors in rhesus monkeys, a result consistent with the differences in the maternal behaviors of these two species. Two of the monkeys who survived to adulthood developed a stereotyped thumb sucking and resultant malocclusions of the front deciduous teeth, whereas the third surviving monkey displayed stereotyped in‐place rockin

ISSN:0012-1630    

DOI:10.1002/dev.420020410

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

年代:1969

数据来源: WILEY

摘要:

AbstractThe cerebellum of rats was irradiated from birth with daily doses of 200r for 1, 2, 3, 4, 5, 8, and 10 days. The animals were killed at fixed periods after irradiation and at various ages for histological evaluation of the cerebellum or they were permitted to survive for a prolonged period for behavioral testing. Gross measurement indicated that anteroposterior growth of the cerebellum was retarded as a function of the number of doses delivered except in animals that received a single dose of of 200 r. A number of pre‐ and post‐weaning qualitative behavioral observations (tremor, ataxia, level of activity) correlated with the retardation of cerebellar development produced by the irradiation schedules, though some behavioral recovery was noted in the older anim

ISSN:0012-1630    

DOI:10.1002/dev.420020411

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

年代:1969

数据来源: WILEY