摘要:

AbstractThis study investigated the possibility that one function of the human infant's cry is to convey individual identity across distance. Six‐hundred adults, having been exposed to 30 s of an infant's crying, were asked to identify this infant on the basis of other, experimentally altered, cries. The cries were altered naturally by rerecording across distance in the out‐of‐doors, and artificially by bandpass filtering and temporal reorganization. The individuality of cries proved remarkably robust to degradation: Only when frequencies were limited to the range of 8 to 10 kHz was recognition performance significantly impaired. It is argued that the human infant's cry, a complex signal with multiple markers of individuality, may have among its functions the communication of infants' identities across distance.© 1994 John Wiley&Son

ISSN:0012-1630    

DOI:10.1002/dev.420270102

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

年代:1994

数据来源: WILEY

摘要:

AbstractThere is increasing concern that environmental stimuli in the Neonatal Intensive Care Unit (NICU) may be detrimental to the preterm infants hospitalized there. Separately, there is longstanding recognition that preterm infants at 40 weeks postconceptional age habituate less reliably than full‐term infants. This study uses a relevant animal model to test whether exposure to NICU sounds, as a single departure from normal neonatal experience, can alter habituation. Chicks were incubated, hatched, and reared in either a quiet or a NICU‐sound environment. Habituation was measured by the length of time that chicks delay their ongoing peeping upon hearing a white noise stimulus. NICU‐sound‐reared 4‐day‐olds failed to habituate, showing as much responsiveness at the end of repeated stimulation as at the beginning. This is, to our knowledge, the first demonstration that atypical sound exposure alone can alter this fundamental aspect of neurosensory competence in an otherwise healty neonate.© 1994 John Wil

ISSN:0012-1630    

DOI:10.1002/dev.420270103

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe examined the influence of the amniotic sac on spontaneous movement in late gestation fetal rats. Using techniques for in vivo observation of fetal behavior, Day 21 rat fetuses were exteriorized from the uterus, with umbilical connections to the dam intact, and videotaped for 15 min either: (a) through the intact amniotic membranes, or (b) following removal of the membranes. Analysis of fetal behavior categories replicated the findings of previous investigators: Movements of the head, forelimbs, and rearlimbs were significantly increased by sac removal, as was the total frequency of behavior categories and the simultaneous occurrence of different behavior categories. Frame‐by‐frame analysis of videotaped behavior revealed that amniotic sac removal increased the frequency of movement bouts without altering the overall amount of time that fetuses spent moving. Movement bout durations ranged from 50 msec to 70 s. The average duration of movement bouts was significantly reduced for fetuses lacking the amniotic sac as compared to fetuses within the sac, as was the overall distribution of movement bout durations. Frequency distributions of movement bout durations and interbout interval (IBIs) revealed that sac removal significantly increased the occurrence of short (1–2 s) movement bouts and reduced the frequency of protracted movement bouts and interbout intervals (>10‐s duration). Taken together, these findings indicate that the quantitative dimensions of fetal rat movements are influenced by proximal features of the uterine environment. During prenatal life, the amniotic sac appears to sustain movement, possibly by providing proprioceptive feedback or physical support to the fetus, or by regulating the chemical milieu.© 1994 John Wiley&S

ISSN:0012-1630    

DOI:10.1002/dev.420270104

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe present series of experiments was designed to determine the dose—response characteristics of the cholecystokinin suppression effect on rat pups ingesting through suckling and adult modes. Pups at 10–22 days of age were deprived of their dam and food for 6 hr. At test time, the subjects received intraperitoneal injections or intravenous infusions of CCK‐8 at 2, 4, 8, or 16 μg/kg in saline, or the saline vehicle alone. The pups were permitted to ingest for 30 min immediately after the injection or during the infusion. Ingestion included taking milk from the dam by suckling or feeding from the substrate. Regardless of the route of administration, CCK‐8 elicited a low level of suppression across all doses and all ages when pups ingested within the natural suckling situation. In marked contrast, pups ingesting from the substrate in the adult mode suppressed their intake of bovine light cream or chow pellets in a dose‐related manner following injections of the peptide. The blockade of the CCK dose‐related suppression effect during suckling indicates that a different set of mechanisms governs intake of milk from the mother. The results may be related to the level of arousal required to sustain motivated behaviors while pups engage in the different modes of ingestion.© 1994 John Wi

ISSN:0012-1630    

DOI:10.1002/dev.420270105

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

年代:1994

数据来源: WILEY

摘要:

AbstractYoung rat pups are dependent on the dam for their survival, thus isolation of the neonatal rat pup from the dam presents the young organism with a variety of stressors. The question examined in this study concerns the ability of the young rat pup to modify its response to isolation following repeated exposure to that isolation as well as the role played by endogenous opiates in this process. Following repeated isolations, pups were seen to decrease vocalization rates. Altering the context in an attempt to dishabituate animals failed to reverse the decreased vocalization rate. However, opiate receptor blockade attenuated this decrease when administered subsequent to the first isolation period but not prior to the last isolation period. These results suggest that the development of this attenuated response to isolation stress is opiate‐mediated but that once established, its expression is not dependent on endogenous opiate release.© 1994 John Wiley&Sons, I

ISSN:0012-1630    

DOI:10.1002/dev.420270106

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

年代:1994

数据来源: WILEY

摘要:

AbstractSeparation‐induced calling in the young of many species can be modulated by the opioid system. Morphine reduces ultrasonic vocalizations (USVs) produced by isolated rat pups, an effect blocked by naltrexone. Central administration of the mu and delta opiate receptor agonists DAMGO and DPDPE reduce USV; kappa receptor agonist U50,488 increases them. We now find that peripheral U50,488 not only boosted calling rates in isolated 3‐, 10‐, and 18‐day‐old rat pups, but also induced calling in pups of these ages tested in the home cage with their littermates, where USVs are seldom heard in nature. U50,488 lowered rectal temperature, although temperature loss and USV were not correlated within drug treatment groups.© 1994 John Wiley

ISSN:0012-1630    

DOI:10.1002/dev.420270107

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

年代:1994

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420270101

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

年代:1994

数据来源: WILEY