摘要:

AbstractWhen the rat mother is permanently removed from her litter at 14–15 days postnatally, weight loss in the pups routinely occurs. We now describe a method by which normal weight gain can be achieved at this age in the absence of the mother. Liquid flowing in a continuous stream down a glass surface in the home cage elicits spontaneous licking from the rat pups. If the liquid is a high fat milk formula, the rat pups maintain normal body weight. They do not maintain normal weight if low fat (bovine) milk is presented in this way or if the high fat milk formula is merely available in a reservoir on the cage floo

ISSN:0012-1630    

DOI:10.1002/dev.420110502

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe developmental course of respiration rate and variability during sleep states and waking was measured in chronically prepared kittens. Kittens had higher respiration rates during active sleep (AS) as compared to quiet sleep (QS) at all ages, with rates declining developmentally in both sleep states. Compared to waking, respiration rate and variability were decreased during sleep. The decrease was greatest in the youngest animals and during QS. Minute‐to‐minute respiratory variability declined from 10 to 40 days of age for each state, whereas breath‐to‐breath variability declined during the same period only during QS. Respiratory variability was higher in AS than QS in older kittens. Heart rate and variability were found to be correlated with respiratory parameters only during QS. These observations support the hypothesis that the control and development of respiration during sleep is achieved by different processes in QS

ISSN:0012-1630    

DOI:10.1002/dev.420110503

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe effects of d‐amphetamine (4 mg/kg), scopolamine (1 mg/kg), methylscopolamine (1 mg/kg), and parachlorophenylalanine (400 mg/kg) on exploration were studied in male rats at 16, 21, and 28 days of age. Amphetamine elicited stereotypy at all ages tested, reduced exploration (measured by the time spent head‐dipping during a 10‐min trial in a holeboard) from Day 21, but did not significantly increase rearing at the ages tested. (Reduced head‐dipping, accompanied by stereotypy, is the pattern of results previously seen in adult rats with this dose of amphetamine.) An interesting difference emerged with scopolamine, which reduced head‐dipping at all the ages tested, whereas in adults it produced an increase. The age‐related difference in drug effects suggests that muscarinic pathways are functioning from Day 16, but that the system concerned with exploration functions differently in mature and immature rats. Both scopolamine and methylscopolamine reduced rearing which suggests that the change is due to peripheral actions of the drugs. Parachlorophenylalanine, which decreases serotonin levels, increased head‐dipping, as it has been found to do

ISSN:0012-1630    

DOI:10.1002/dev.420110504

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

年代:1978

数据来源: WILEY

摘要:

AbstractPups of primiparous and multiparous Sprague Dawley rats received 0‐, 2‐, or 5‐min cold stress on Days 2–6 postpartum. Stressed offspring of primiparous mothers had shorter latencies to move in an open field than did control offspring of primiparous mothers. However, stressed offspring of multiparous mothers had longer latencies than did the controls. The results suggest differences in maternal responsiveness immediately following return of stressed pups to t

ISSN:0012-1630    

DOI:10.1002/dev.420110505

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

年代:1978

数据来源: WILEY

摘要:

AbstractConditioned auditory discrimination and extinction of the skin potential response were attempted in 4‐month‐old infants using interstimulus intervals of 1500, 3500, 5500, and 7500 msec. Half of the infants in each of the interstimulus interval groups were defined as high magnitude orienters and half were low magnitude orienters. Conditioning was successful with the 5500‐ and 7500‐msec interstimulus intervals, but not with the 1500‐ and 3500‐msec intervals. Analysis of individual subject data indicated that individual differences in conditionability were related to interstimulus interval and orienting response magnitude. Also, those subjects discriminating at the longer intervals tended to be high magnitude orienters. In other words, longer interstimulus intervals interacted with a high magnitude of orienting to facilitate conditioning. The results were taken as evidence that individual differences in the magnitude of the orienting response reflect different individual needs in stimulus information proc

ISSN:0012-1630    

DOI:10.1002/dev.420110506

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

年代:1978

数据来源: WILEY

摘要:

AbstractThree pigtail infant monkeys (Macaca nemestrina) were separated from their mothers shortly after birth and raised in social isolation on cloth surrogates. At about 24 weeks of age they were surgically implanted with multichannel biotelemetry systems. Following the collection of baseline behavioral and physiological data, the cloth surrogates were removed for 4 days, then returned. The behavioral and physiological (heart rate, body temperature, sleep patterns) reaction to separation from the surrogate was much less intense than is the case in group‐living pigtail infants that are separated from their mothers, suggesting that the attachment bond to a cloth surrogate may well be different than the bond to a living mother in a social group. Heart rate mean values and variability were similar in surrogate‐reared and mother‐reared infants, suggesting a degree of environmental independence in heart rate regul

ISSN:0012-1630    

DOI:10.1002/dev.420110507

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe presence of a thermal gradient in the home cage and its use in home orientation was studied in kittens from shortly after birth to 2 weeks. Responses on a thermal gradient outside the home cage were also studied. With the home region and a freshly washed cage floor either cooled or warmed, kittens were placed in the adjacent corner or the home. In one study kittens chose between a cooled home and a warmed diagonal region. On a thermal gradient kittens exhibited thermotaxic turning and thermokinetic response. Kittens initially used either thermal or olfactory cues to reach the home but began to use only olfactory cues towards the end of the 1st week. Similarly, warmth in the home region caused “settling” during the 1st week but thereafter warmth and olfactory cues were most effective. Kittens chose the cooled home region more often than the warmed diagonal corner responding to olfactory over thermal c

ISSN:0012-1630    

DOI:10.1002/dev.420110508

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe specificity of maternal‐home cage odors governing home orientation was tested in 8‐ to 11‐day‐old kittens. Kittens were first tested for home orientation from the adjacent corner in their own home cages and cages of other mothers with litters of the same age. The majority of kittens oriented successfully in their own cages but not in strange mothers' cages. They then lived for 48 hr in the strange mothers' cages. At the end of this time they showed no improvement in orientation in their own home cages. Moreover, after an additional 24 hr in their own home cages they showed no improvement in their own home cage. Home orientation involves 2 odor components: 1 general to different mothers and 1 specific to each

ISSN:0012-1630    

DOI:10.1002/dev.420110509

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

年代:1978

数据来源: WILEY

摘要:

AbstractAlthough the influence of light on the infant rat before Day 14, when its eyelids open, are presumed to be minimal, we have shown that as early as postnatal Day 6, male and female albino rats demonstrate negative phototaxis. Bilateral enucleation eliminates negative phototaxis. whereas unilateral enucleation does not. Rearing in the dark does not prevent the expression of the behavior. Knife cuts on postnatal Day 5, which undercut the dorsal midbrain involving the superior colliculus, prevent the expression of this response to light. Unilateral dorsal midbrain knife cuts and posterior cortex lesions have no effect. These results call attention to an early period in the postnatal development of the rat when it is capable of exhibiting negative phototaxis. The superior colliculus in the dorsal midbrain appears to be crucial for demonstrating this behavior.

ISSN:0012-1630    

DOI:10.1002/dev.420110510

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

年代:1978

数据来源: WILEY

摘要:

AbstractStumptailed monkeys were reared from 1 week after birth to 6 months of age in either a colony condition with the mother or in partial social isolation that allowed visual contact with the colony animals, but not physical contact. At 6 months of age the animals were killed and selected areas of the neocortex stained by the Golgi‐Cox method. Relatively nonspiney cells of Layer IV were drawn and analyzed for complexity of dendritic branching. Isolation‐reared animals had significantly decreased branching complexity in Motor I cortex when compared to the control animals. A transform of the data that related the number of branches to the number of previous branches showed a slight rearing effect in Somatosensory I cortex with the deprived animals having a lower rate of branching than the controls. We conclude that social isolation also includes a motoric deprivation that could account for these d

ISSN:0012-1630    

DOI:10.1002/dev.420110511

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

年代:1978

数据来源: WILEY