摘要:

AbstractRats whose mothers were maintained on either a 25% casein diet or an 8% casein diet and who were provided the same diet after weaning were tested on delayed spatial alternation or on one of a series of spatial localization problems using the Morris maze (Morris, 1981). Malnourished rats demonstrated perseverative deficits in the form of strings of consecutive errors on the delayed spatial alternation. Performance in the Morris maze indicated spatial localization ability and spatial memory processes were not impaired by chronic malnutrition in rats. The data suggest that complex processing of spatial information that includes flexible use of place cues over short intervals is impaired by malnutrition, while spatial localizationper seand spatial mapping are not affected.

ISSN:0012-1630    

DOI:10.1002/dev.420190102

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

年代:1986

数据来源: WILEY

摘要:

AbstractHuman infants less than 4 months of age ingested water and moderate concentrations of sodium chloride solution (0.10–0.20M) in equal amounts. In contrast, infants 4–24 months of age exhibited heightened acceptance of saline solution relative to water. Such a developmental change in salt acceptability is consistent with a hypothesis of postnatal maturation of peripheral and/or central structures underlying this response. Children 31–60 months of age tended to reject saline solution relative to water. This change may in part reflect the effects of exper

ISSN:0012-1630    

DOI:10.1002/dev.420190103

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

年代:1986

数据来源: WILEY

摘要:

AbstractPrevious research has demonstrated that exposure to 90 sec of hind paw shock activates an endogenous pain control system that involves cholinergic sites. The purpose of the present investigation was to examine the development of function of this nonopioid analgesic system. Research on the ontogeny of the cholinergic system suggests that this receptor system exhibits an extended period of postnatal development, with various neurochemical indexes reaching maturity between 30 to 50 days of age. Results revealed that exposure to hind paw shock produced very low levels of analgesia in 10‐ and 28‐day‐old rats. The analgesic response was more evident in 2‐month‐old rats, but the degree of hind paw schock‐induced analgesia was not at its maximum until 3 months of age. Systemic injection of naltrexone had no effect on the degree of analgesia induced by hind paw shock, while a systemic injection of scopolamine significantly attenuated the analgesia displayed by the 28‐day‐old and 2‐ and 3‐month‐old rats. Thus, the neurochemical indexes of cholinergic development overestimated the degree of functional maturity of the endogenous analgesia system activa

ISSN:0012-1630    

DOI:10.1002/dev.420190104

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of home cage environmental stimuli on learning and the effects on retention of the presence or absence of these familiar contextual training stimuli during the retention test (Experiment 1) or during the retention interval (Experiment 2) were examined using 10‐day‐old rats, a multidirectional active avoidance task, and a 30‐min retention intrval. Home cage environmental stimuli were found to improve learning. A change in stimuli immediately after training, during the 30‐min retention interval, was found to have a greater impact on retention performance than stimulus change introduced at the time of the retention test. The implications of these findings are discussed in relation to ontogenetic differences in retention performance and theories of for

ISSN:0012-1630    

DOI:10.1002/dev.420190105

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

年代:1986

数据来源: WILEY

摘要:

AbstractIndividually reared mother‐infant dyads of crab‐eating monkeys (Macaca fascicularis) were observed cross‐sectionally in their mother‐infant relationship. In infants aged from 0 to 5.0 months, rather drastic changes were found both at 0.5–1.0 and 2.0–3.0 months of age. For an explanation of these changes, developmental processes of discrimination between mother and infant were analyzed cross‐sectionally by exchanging mother‐infant combinations. The results indicated that the first 0.5 months postpartum was characterized as a behaviorally nondiscriminating stage where nipple discrimination by infants was the only exception. The latter half of the first month was the beginning of a nonaggressive discrimination stage by mothers, indicated by lipsmacking and sniffing and in infants by clinging. When infants reached the age of 2.0–3.0 months, the mothers' nonaggressive discimination with lipsmacking decreased, and her aggressive discrimination of alien infants increased. In addition to maternal visual discrimination of infants' physical appearances, differences in infants' odor and/or their method of nipple contact were suggested to affect the mothers' diffe

ISSN:0012-1630    

DOI:10.1002/dev.420190106

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

年代:1986

数据来源: WILEY

摘要:

AbstractTwo studies examined the theory that early limitations on sensory functioning contribute to the organization of a structure for perceptual development and intersensory functioning. Rat pups' eyelids were surgically opened on Day 7, following which the development of homing to their nest site was investigated, with each animal alone in its living cage. Control pups increased homing until Day 14, and then decreased. Experimental pups showed no such decline, with the highest rate of homing evident on the last day of testing. The importance of visual cues for this altered development of homing was examined. Visual cues for the home were reduced by removing all shavings during testing, while leaving an odorous substrate in place. Under these conditions, both groups showed the characteristic increase and decline in homing, suggesting that premature eyelid opening results in a modification of the distribution of attention to visual and olfactory characteristics of the nest.

ISSN:0012-1630    

DOI:10.1002/dev.420190107

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

年代:1986

数据来源: WILEY

摘要:

AbstractPostural control skills and quadrupedal locomotor pattern in infant rolling mice, a neurological mutant, were observed in the following situations: hindlimb support when suspended, rope descent, narrow path traverse, quadrupedal locomotion on an inclined corridor, and swimming behavior when entirely submerged. Until the second week of age, rolling mice developed primitive responses similar to, or somewhat slower than, their unaffected littermates, but failed to show mature adaptive and coordinated movements from Days 16–18 onward in hinblimb support and rope descent tests. The gait was broadbased and they frequently lurched, rolled over on the side in the narrow‐path and incline situations. Also, swimming behavior was extremely clumsy with varying degrees of disturbed rhythm and inconsistent movement of hindlimb paddling. These findings might result from an immature development of hindlimb muscle tonus control system and distortion of smooth and orderly sequence of hindlimb muscular contractions which characterize skillful quadrupedal locomot

ISSN:0012-1630    

DOI:10.1002/dev.420190108

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

年代:1986

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420190109

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

年代:1986

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420190101

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

年代:1986

数据来源: WILEY