摘要:

AbstractResponses of recently parturient ewes to their familiar versus separated (i.e., unfamiliar) twin lambs were observed in an attempt to elucidate further the characteristics of the phenotypic traits (signatures) mediating maternal recognition and bonding. Ewes responded more positively to their familiar lamb than to its twin that had been isolated at birth. Nonetheless, those same mothers also discriminated between their separated twin and unfamiliar alien lambs. Alien lambs elicited similar rejection behavior regardless of whether they had been housed with their own mother or in isolation prior to testing. Lambs appear to have individually distinct (olfactory) signatures; however, the signatures of twin siblings may be sufficiently similar to enable the mother to detect a resemblance. No evidence suggests that acquired maternal labels play a role in either the acceptance of the ewe's own lamb(s) or rejection of aliens.

ISSN:0012-1630    

DOI:10.1002/dev.420240302

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis study evaluated the immunological, hormonal, and behavioral responses of juvenile squirrel monkeys to repeated social separations of varying length. Following a 3‐hr separation, lymphocyte responses to stimulation with the mitogen concanavalin A (Con A) declined significantly, and these alterations were sustained after a 24‐hr separation period. The responses to Con A and to a second mitogen, phytohemagglutinin (PHA), were suppressed after 2 days. At the end of a 7‐day separation period, immune responses were not significantly different from basal values. Plasma cortisol levels were elevated above basal levels in all animals after the 3‐hr, 24‐hr, and 2‐day separations, but were not elevated after the 7‐day separation. While we observed no statistivally significant changes in locomotor activity or calling behavior during any of the separations, the monkeys tended to be most active and to call most immediately following separation. Our findings concur with earlier reports indicating that social strressors can influence lymphocyte proliferation in nonhuman primates and that certain cell types might be differentially sensitive to stress, but also indicate that these influences

ISSN:0012-1630    

DOI:10.1002/dev.420240303

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

年代:1991

数据来源: WILEY

摘要:

AbstractNine isolate and 6 socially reared adult rhesus monkeys were examined in a standard blocking procedure. A tone was paired with a startle stimulus (US) during Phase 1. A tone‐light compound CS was paired with a US during Phase 2. In Phase 3, the light was presented alone to test for blocking. Results showed that learning about the light was blocked in social controls, but not in isolates. These data suggest isolates processed information atypically, in that they developed an association to a redundant cue. A second group of isolates (n=3) underwent the identical procedures. However, conditioned reactions to the tone were extinguished before testing. Test responding was significantly reduced in this group, that is, blocking was obtained. These data suggest the within‐compound association developed during Phase 2 mediated the isolate blocking deficit. Together, these findings imply long‐term intellectual consequences of early social impoverishment. Such deficits may be mediated by alterations in central dopamine sy

ISSN:0012-1630    

DOI:10.1002/dev.420240304

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

年代:1991

数据来源: WILEY

摘要:

AbstractContextual stimuli may influence conditioned behavior in at least two ways (e.g. Bouton&Bolles, 1985). By becoming associated with the unconditioned stimulus (US), context cues can acquire excitatory strength that facilitates responding to a phasic conditioned stimulus (CS). The context also function to clarify the meaning of an ambiguous CS. Data obtained with an appetitive Pavlovian conditioning paradigm suggest that the processes mediating these two influences of context are dissoci‐ during development. Evidence of context‐US associations was observed in rats that began training Postnatal Day 17, but no evidence for a disambiguation function was found until pups were 20‐ to days‐old. Evidence for a context‐US association was obtained by demonstrating that US alone presentations in the training context restored conditioned responding to an extinguished CS. Evidence disambiguation function was obtained by demonstrating that a context shift, concurrent with extinction of responding to a phasic CS, preserved responding to the CS when the subjects were subsequently tested in the training context. These findings were discussed in relation to (a) the development of the rat's ability to use relational representations, and (b) Nadel and Zola‐Morgan's (1984) hypothesis linking hippocampal maturation to the role of context during

ISSN:0012-1630    

DOI:10.1002/dev.420240305

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

年代:1991

数据来源: WILEY

摘要:

AbstractFischer 344 (F344) rats and Syrian hamsters, unlike rats of the Sprague‐Dawley or Wistar strains, exhibit an aversion to dilute NaCl solutions as adults. In the present studies, using the anterior intraoral infusion method, it is shown that both F344 rats and hamsters accept more dilute NaCl than either water or concentrated NaCl (i.e., show a “single bottle” preference/aversion function identical to Sprague‐Dawley rats) at both 6 and 18 days of age. At 18 days of age, they also show a preference for dilute NaCl over water in a simultaneous choice paradigm. In contrast, only 1‐3 days later when these animals are weaned, they strongly reject NaCl solutions from sipper tubes in favor of water. It is unlikely that an abrupt discontinuity in neurosensory development can fully explain this dramatic reversal in salt a

ISSN:0012-1630    

DOI:10.1002/dev.420240306

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

年代:1991

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420240301

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

年代:1991

数据来源: WILEY