摘要:

AbstractBy 20 days of age, dehydration produces a clear anorexia, even though weanling rats have had only limited feeding and drinking experience. Their lack of ingestive experience makes weanlings good subjects for studying the physiological mechanisms subserving anorexic phenomena because learned contributions are unlikely to add significant complications. Twenty‐day‐old rats dehydrated by hypertonic saline injection were anorexic when offered milk or solid food (rat chow), but not when offered sucrose solutions (Experiment I). However, when the scent of almond was associated with sucrose solutions, or with water, intake of these solutions was depressed by dehydration (Experiment II). Thus for dehydrated rats, olfactory stimulation may help produce dehydrationinduced anorexia. Making rats anosmic by intransal lavage with ZnSO4(Experiment III) eliminated the anorexia to almond‐scented water and partially eliminated that to milk. For these fluids, an odor cue seems a requirement for the occurrence of dehydration‐anorexia. In Experiment IV, we found that dehydration‐anorexia did not occur when milk was infused directly into pups' mouths. This finding suggests that the inhibitory process mediating dehydration‐anorexia influences the approach to food and not the actual consumatory response that occurs once food is in the mouth. The inhibition of feeding produced by dehydration, therefore, may depend largely on olfactory cues, and seems to operate at a distance, as rats locate and ap

ISSN:0012-1630    

DOI:10.1002/dev.420150602

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe domestic mallard duck embryo must be exposed to its embryonic contact‐contentment call at a repetition rate of 4 notes/sec if the neonate is to show the species‐typical preference for the maternal call at its normal rate (3.7 notes/sec) after hatching. Exposing the embryo to the contact call at either 2.1 notes/sec or 5.8 notes/sec is no more effective than no auditory experience at all. To determine if there is a critical period for exposure, embryos were exposed to the 4 notes/sec call either before or after hatching. Both periods proved equally effective provided only that a 48‐hr “consolidation” period was allowed to intervene between stimulation and testing. That is, the birds tested 24 hr after prenatal or postnatal stimulation behaved as if they were not stimulated at all. The present study was undertaken to determine whether the curious requirement for a consolidation period is a normal developmental phenomenon or a consequence of limiting the birds to exposure to a call with an abnormally invariant repetition rate of 4 notes/sec. To that end, embryos were stimulated with the same call as before but at variable rates of 2.1, 4, and 5.8 notes/sec, as happens under normal conditions of development. In this case, the neonates had no need for a consolidation period and showed the species‐typical preference at 24 hr after hatching. Thus the previous results were a consequence of an abnormally narrow range of embryonic auditory stimulation. A 2nd experiment showed that, if the birds' postnatal perception was to be normal, the embryos could not be merely exposed to the rhythmic component of the contact call, but had to experience the characteristic frequency modulation of the call as well.These results indicate that we require surprisingly detailed information about the sensory stimulation present during the usual course of development of our subject species if we are to give an appropriate interpretation to the results of early experiential and critical period manipulations. Knowledge of usual sensory‐stimulative variations has not been a conspicuous feature of developmental psychobiological studie

ISSN:0012-1630    

DOI:10.1002/dev.420150603

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

年代:1982

数据来源: WILEY

摘要:

AbstractHeart period, heart period variability, and respiration frequency were observed and compared longitudinally in rats from birth to 24 days of age. In addition,V, a quantification of respiratory sinus arrhythmia derived via spectral analysis of the heart period pattern, was observed. It was hypothesized that these heart period parameters would be differentially sensitive to the neural control of the heart and would, therefore, reflect different developmental patterns. Heart period and heart period variability indicated developmental patterns consistent with the literature. The ontogeny ofVsuggests that it may represent the developmental pattern of tonic vagal influences on the heart.

ISSN:0012-1630    

DOI:10.1002/dev.420150604

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

年代:1982

数据来源: WILEY

摘要:

AbstractNutritive deprivation, suckling deprivation, gastronintestinal fill, and milk availability contribute to the control of sucking (as measured by jaw‐muscle electromyograph) and ingestion of milk (provided via a tongue cannula) in 11–13‐day‐old rat pups. Depriving pups of the opportunity to suckle reliably increases subsequent sucking and milk intake. Intraoral delivery of milk also increases sucking, regardless of whether or not pups are suckling‐deprived. Gastrointestinal preloads have no effect on sucking if pups are not receiving milk, but reliably block the increase in sucking which accompanies milk delivery. Finally, milk delivered to the pup's mouth prior to a suckling opportunity can either enhance or attenuate subsequent sucking depending on whether pups are allowed to consume milk while suckling. In all cases, a particular mode of sucking (“rhythmic” sucking) is most affected by experimental manipulation, and appears to be an important component of the pup's inges

ISSN:0012-1630    

DOI:10.1002/dev.420150605

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

年代:1982

数据来源: WILEY

摘要:

AbstractVaried milk delivery contingencies differentially affect sucking in rat pups as measured by jaw‐muscle electromyographic activity. In Experiment I we found that 11–13‐day‐old pups sucked more frequently when receiving tiny intermittent pulses of milk than when receiving no milk, and continued to suck at a high rate for at least 30 min after cessation of milk delivery. In subsequent experiments we found that pups 13–18 days of age engaged in more frequent sucking if receiving milk continuosly rather than intermittently, and that this increased rate of sucking persisted for at least 24 hr after cessation of milk delivery. Pups given experience with continuous milk delivery from 14 to 18 days of age also spent significantly more time attached to the nipple at 19 days of age than did pups in control groups. It was concluded that experience with different milk delivery schedules can affect subsequent sucking and nipple attachment

ISSN:0012-1630    

DOI:10.1002/dev.420150606

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe patterns of distances maintained between 30 children and 15 adult caretakers were measured to determine developmental trends in children's patterns of interpersonal spacing toward adults and playmates. Children's positions during free play were photographed at 60‐sec intervals and analyzed with a computer to determine the mean distances children maintained toward their 1st through 5th nearest adult caretakers and toward their 1st through 5th nearst playmates. Children's distances from adults increased with age, while distances from playmates and spatial variability decreased with age. Only infants (6–18 months) stayed significantly close to any of their adult caretakers; toddlers (19–27 months) and preschoolers (30–60 months) avoided proximity to their 3rd through 5th nearest adult caretakers more than could be expected by chance. All age groups significantly avoided proximity to their 4th and 5th nearest playmates; avoidance of playmates' space decreased w

ISSN:0012-1630    

DOI:10.1002/dev.420150607

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

年代:1982

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420150608

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

年代:1982

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420150601

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

年代:1982

数据来源: WILEY