摘要:

AbstractVisual cliff behavior was studied in 120 chicks as a function of 22, 46, 70, 94, or 118 hr of rearing in a deep or shallow environment. Preference for the deep side of the visual cliff increased directly with duration of depth‐rearing but was uninfluenced at any duration of shallow‐rearing. Although qualitative differences existed in the behaviors of those shallow‐ and deep‐reared chicks which crossed the cliff, the loss of depth avoidance by the latter group appeared to be specific to the rearing and testing ap

ISSN:0012-1630    

DOI:10.1002/dev.420090102

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

年代:1976

数据来源: WILEY

摘要:

AbstractThis study investigated biochemical substrates of the continuous stimulation effect, i.e., the developmental phenomenon whereby continuous stimulation depresses arousal level. Neonatal rats were injected intracisternally with 6‐hydroxydopamine. Motility, heart rate, and brain amines were measured in these animals, as well as in injected and noninjected control animals, at 14 and 28 days of age in an own‐control design with and without continuous auditory stimulation. Brain norepinephrine was significantly and inversely related to the magnitude of the continuous stimulation effect and experimental‐control differences increased with age. These results indicate that an intact catecholaminergic system is necessary for the mediation of increased arousal during stimul

ISSN:0012-1630    

DOI:10.1002/dev.420090103

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

年代:1976

数据来源: WILEY

摘要:

AbstractSamples of mice from each of 6 inbred strains were tested for audiogenic and electroconvulsive seizures at 5 ages (14, 21, 28, 35, and 42 days). A moderately large within‐strain correlation (.67) was found, indicating that developmental patterns of susceptibility to audiogenic and electroconvulsive seizures are similar within each strain. The finding of an even larger between‐strain correlation (.91) indicated that strains which are highly susceptible to audiogenic seizures are also likely to be highly susceptible to electroconvulsive seizures.In a 2nd experiment, whole brain norepinephrine and serotonin were assayed in each of 5 inbred strains at 21 and 42 days of age. Results were consistent with the hypothesis that levels of these amines are inversely related to seizure susceptibility. Mice from strains which were susceptible to seizures at 21 days of age had significantly lower levels of norepinephrine and serotonin in brain than did 42‐day‐old, seizure‐resistan

ISSN:0012-1630    

DOI:10.1002/dev.420090104

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

年代:1976

数据来源: WILEY

摘要:

AbstractMice given a single large dose of corticosterone at 2 days of age, and tested when adult, have shown lasting alterations in operant behavior, associated with reductions in cerebral weight and DNA content. When mice were given corticosterone at 22 days, no changes appeared in cerebral weight, DNA, or in operant behavior, but an apparent decrease did occur in open‐field activity. The results suggest that the effects of corticosterone treatment at 2 days on the developing brain are mediated by one or more types of sensitivity to the steroid that have been largely lost by 22 day

ISSN:0012-1630    

DOI:10.1002/dev.420090105

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

年代:1976

数据来源: WILEY

摘要:

AbstractA single eye of young chicks was sewed shut for various times. Regions contralateral to and primarily or secondarily innervated by the sutured eye had a reduced rate of cerebral blood flow in comparison to the corresponding ipsilateral regions. However, upon reopening the sutured eye after 2 days, these contralateral regions (optic lobes and cerebral hemispheres) exhibited a rapidincreasein cerebral blood flow to a level significantly above that in control ipsilateral areas. The duration of this effect was considerably prolonged in chicks that were monocularly sutured immediately after hatching without prior exposure to light. Chicks that had 1 week of normal vision before monocular suture did not show this overcompensatory effect. If the period of monocular suture was extended to 7 days before restoration of vision to the occluded eye, the overcompensatory vascular effect was delayed. The maximal effect was apparent only upon the 1st exposure of an eye to major visual input. A possible relation exists between this rapid increase in regional blood flow and the period when visual imprinting could normally be expected to be maximal.

ISSN:0012-1630    

DOI:10.1002/dev.420090106

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

年代:1976

数据来源: WILEY

摘要:

AbstractRat pups were undernourished from birth by placing them for 12 hr/day with a normal lactating mother and 12 hr/day with a nipple‐ligated mother each day for 25 days. The method resulted in a marked delay in the body growth of the undernourished pups, especially during the first 2 weeks of life. Observations of the behavior of the mothers towards the underfed pups were made at different times of the day and compared to the behavior of the mothers suckling well‐fed pups. The results show that (1) nipple‐ligated mothers are able to provide adequate maternal care for undernourished pups, and (2) both ligated and nonligated mothers caring for underfed pups spend more time with those pups than mothers caring for well‐f

ISSN:0012-1630    

DOI:10.1002/dev.420090107

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

年代:1976

数据来源: WILEY

摘要:

AbstractIncubating chicks were presented with a high‐intensity or low‐intensity photic flicker stimulus, or with no photic stimulation. The chicks were tested at 16 hr posthatching for approach behavior, or at 96 hr for imprinting performance to the 2 visual flicker stimuli. The data were analyzed in accord with the arguments of whether those stimuli that effectively elicit approach behavior are determined by interaction between maturation and experience or by a genetic program. The results show that prehatch exposure to photic flicker stimuli affects initial approach behavior and imprinting performance, supporting the interaction position in opposition to the genetically programmed posit

ISSN:0012-1630    

DOI:10.1002/dev.420090108

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

年代:1976

数据来源: WILEY

摘要:

AbstractC57BL/6J mice, not susceptible to audiogenic seizures (AGS) on the 1st exposure to an acoustic stimulus, were exposed to the acoustic stimulus for 1 min and then tested at some later date (acoustic priming). They were first exposed at either 8, 16, 19, 22, or 28 days of age, and then tested for AGS 2‐16 days after priming. DBA/2J mice, susceptible to AGS on the 1st exposure to intense noise, were exposed to the acoustic stimulus at 26 days of age, and then again 2‐14 days later. Data indicate that the incidence of AGS upon the 2nd exposure to the acoustic stimulus is a function of age at priming, the prime‐to‐test interval in days, and the index of seizures. In the case of DBA mice, later effects are also dependent on the initial level of

ISSN:0012-1630    

DOI:10.1002/dev.420090109

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

年代:1976

数据来源: WILEY

摘要:

AbstractFive groups of female rats which were exposed to thiouracil for varying periods around the time of birth were compared with a 6th group of untreated controls in motivational, metabolic, and hormonal test situations during adolescence and adulthood. The thiouracil‐treated rats displayed reduced fearfulness in lever‐touching and lever‐pressing tasks in operant conditioning chambers and in their initial adaptation to activity‐wheel and maze apparatuses. These rats also showed hyperactivity in asymptotic running‐wheel performance, increased spontaneous recovery of extinguished lever‐pressing, and elevated responding in lever‐pressing for variable‐interval food reinforcement. A supplemental study revealed significantly greaterad libitumfood and water intake and oxygen consumption in male thiouracil‐treated rats and elevated serum thyroxine levels in thioracil‐treated females. In general the results indicate that perinatal thyroid deficiency engenders a chronic hypermetabolic state in both sexes which may be associated with a persistent, mild hyperthyroid condition in the

ISSN:0012-1630    

DOI:10.1002/dev.420090110

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

年代:1976

数据来源: WILEY

摘要:

AbstractFour juvenile rhesus monkeys responded to the coo‐type vocalization of their respective mothers by increasing dramatically their own vocalization rate and their locomotor activities. The juveniles appeared quite disturbed when they heard their mothers voices and this disturbance was, with one exception, apparently specific to their own mother

ISSN:0012-1630    

DOI:10.1002/dev.420090111

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

年代:1976

数据来源: WILEY