摘要:

AbstractPrevious research has indicated that preexposing animals to intense stimulation leads to subsequent decrements in exploratory behavior. The present study was an attempt to determine if early handling could “buffer” animals against intense stimulation effects. At birth, rat pups were assigned to either a handling or a nonhandling condition. As adults, they received either intense, moderate, or no stimulation prior to being allowed 3 min of visual exploration. The predictions were: (1) handled animals will show significantly more exploration than nonhandled animals; (2) intensely stimulated animals will show significantly less exploration than animals receiving lower amounts of stimulation; (3) handled animals, under intense stimulation, will show significantly more exploration than nonhandled animals under intense stimulation. The results supported the 2nd and 3rd predictions. The first prediction was supported, but was complicated by a Sex x Handling interact

ISSN:0012-1630    

DOI:10.1002/dev.420070502

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe authors attempted to isolate tactile stimulation as a major independent variable treatment and to investigate the effects of 2 levels of neonatal tactile stimulation on the ontogenesis of emotional reactivity in BALB/c mice. The findings of this study strongly indicate differential reactivity as a function of intensity of tactile stimulation, with moderate levels of intensity producing the lowest levels of emotionality and the highest levels producing the highest emotionality.

ISSN:0012-1630    

DOI:10.1002/dev.420070503

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

年代:1974

数据来源: WILEY

摘要:

AbstractPregnant female rats were induced to show maternal behavior by continuous exposure to 5‐10 day old pups. Prepartum suckling continuing into the immediate postpartum period (when the new litter was present) resulted in a high rate of mortality among the newborn. Preventing suckling by the older pups by sealing their mouths with collodion or removing them within 17 hr before parturition restored the normal low rate of pup mortality. Examination showed that pre‐ and early postpartum suckling by the older pups had damaged the mother's nipples preventing the delivery of milk to the newborn. Presumably, the mother's nipples are hormonally conditioned to respond to the sucking of newborn at parturition and become gradually adapted to the increased suckling strength of older pups as nursing proce

ISSN:0012-1630    

DOI:10.1002/dev.420070504

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

年代:1974

数据来源: WILEY

摘要:

AbstractIn 4‐12 month human infants a briefly applied hand sock frequently resulted in marked prehensile disuse of the socked arm (SA) in excess of the sock's mechanical restriction. Most infants failed to reach with the SA for midline objects on a majority of trials while continuing to use the unsocked arm (UA). The SA grasp and manipulation efforts were also reduced. The onset of disuse was rapid, as was resumption of use after sock removal. The SA disuse was attributed to the effect of excess contactual input from the SA. The character of the disuse differed with age. Whereas younger infants often appeared not to recognize the option to attempt prehension with the SA, older ones were capable at times of deliberate disuse of the arm and could reverse existing patterns of SA disuse. Older infants also displayed: (1) better awareness of the handicapping effects of the sock in the framework of an improved concept of arm structure and function, and (2) better adaptive and compensatory responses including substitute use of the UA. These data were interpreted to suggest a general transition from peripheral to central control of prehensile intention during the 2nd half of the 1st yea

ISSN:0012-1630    

DOI:10.1002/dev.420070505

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

年代:1974

数据来源: WILEY

摘要:

AbstractWeanling and adult rats were exposed to either 0 or 10 conditioned stimulus (CS) presentations prior to 1‐way active‐avoidance (AA) training. Although CS exposure retarded avoidance acquisition in the adults, it produced no effect in the pups during avoidance learning. Neither adult nor young rats demonstrated preexposure effects in extinction. A general extinction analysis showed that pups had less resistance to extinction than the adults, despite a comparable avoidance learning criterion between age groups. The lack of preexposure influences on performance by the pups was compared to previous findings of response inhibitory deficits in immature rats. The results were considered in light of selective attention interpretations of latent inhibit

ISSN:0012-1630    

DOI:10.1002/dev.420070506

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

年代:1974

数据来源: WILEY

摘要:

AbstractOffspring of C57BL/6J mice injected with d‐amphetamine sulfate during the last third of pregnancy had slightly reduced body weight at birth, altered concentrations of catecholamines (CA's) in their brains during development, and increased activity after they had matured. Norepinephrine concentrations were depressed at birth, returned to control values by Day 3, and were elevated at 21 and 30 days after birth. Dopamine values were elevated at 30 days after birth. At 75 days of age, animals prenatally exposed to the drug had CA concentrations similar to controls, but had heightened activity levels compared to controls tested in the open field. The results of these experiments demonstrate that d‐amphetamine sulfate administered to mice during the last third of pregnancy produce transient alterations in CA concentrations and long‐lasting changes in beh

ISSN:0012-1630    

DOI:10.1002/dev.420070507

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

年代:1974

数据来源: WILEY

摘要:

AbstractInfant development in 2 prosimian species‐‐greater galago and slow loris‐‐was studied in 2 ways. First, the initial appearance and/or the eventual disappearance of various simple motor behaviors in infants was recorded. Second, the time spent by mothers and infants in contact, near, and away from each other was measured during the first 10 weeks of life. The aim was to see how the 2 sets of measures relate to each other and also to compare the 2 prosimian species with each other and with other primates. The results showed that: (1) contrary to the views advanced by some authors, the speed with which simple motor behaviors attain the adult form is not related in any consistent way to phyletic status, age at which sexual maturity is reached, or the mother's ability to provide manual support for her infant; (2) the pattern of mother‐infant interaction is more variable in prosimian than in anthropoid primates; and (3) the disappearance of involuntary foot‐grasping coincides with the initiatior of infant independence from

ISSN:0012-1630    

DOI:10.1002/dev.420070508

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

年代:1974

数据来源: WILEY

摘要:

AbstractTwelve clinically normal neonates were presented with a battery of sound stimuli while their behavior was assessed live by 2 sound‐masked observers and simultaneously videorecorded. This procedure was performed for the baby's whole body aspect and also for the head aspect only in a 31/2X “close‐up”. Later, the same observers assessed the behavior from the videorecords. In both situations, observers were permitted to see the babies for 10 sec at each trial. The first 5 sec was a prestimulus observation period and the second 5 sec usually contained a sound stimulus. Between trials the observers were allowed 20 sec in which to note (1) prestimulus activity; (2) confidence in response; and (3) facial, digit, and limb movements and “wholistic” impressions (e.g., “stilling”). The agreement between live and video assessments was slightly better than the level of interobserver agreement (Pearson's contingency coefficients). The use of videorecording caused, at most, slight losses of relevant information and, apparently, did not generally disto

ISSN:0012-1630    

DOI:10.1002/dev.420070509

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

年代:1974

数据来源: WILEY

摘要:

AbstractRats 6, 10, and 15 days of age were tested on acquisition and reversal of position and tactile discrimination tasks in a 2‐choice situation using access to the home cage as reinforcement. In the early trials the 6‐day group often failed to respond due to locomotor immaturity. But, despite the missed opportunities, they mastered the position habit in about the same number of choice trials as the 10‐day group. However, the 15‐day group was superior to the 2 younger groups. In tactile discrimination these subgroups differed significantly in learning to select the rough or smooth surfaces both in acquisition and reversal. On both the spatial and the tactile discrimination tasks the animals older than 2 weeks showed improvement in learning

ISSN:0012-1630    

DOI:10.1002/dev.420070510

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe activity of indolethylamine‐N‐methyltransferase (INMT) from the rabbit lung is relatively high in the newborn and increases rapidly after birth, attaining its maximum level at 15 days of age. Between the 15th and 19th postnatal days, INMT activity declines to the mature level and remains fairly constant thereafter. The decrease in the activity of the enzyme may be due to the presence of dialyzable endogenous inhibitor(s). The inhibition of the enzyme from lungs of rabbits of varying ages byS‐adenosylhomocysteine (SAH),N, Ndimethyltryptamine (DMT), and chlorpromazine (CPZ) is rep

ISSN:0012-1630    

DOI:10.1002/dev.420070511

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

年代:1974

数据来源: WILEY