摘要:

AbstractIn these studies, descriptive information on the diet and feeding behavior of ring dove squab is considered in the context of an analysis of the mechanisms underlying the development of eating. Experiment I shows that squab begin to peck at grain around Day 13 and both the rate and efficiency of pecking increase through Day 21 when the squab are weaned. Experiment II shows that squab reared without seed in their home cage do not develop normal levels of pecking unless exposure to seed is followed in close temporal proximity by interaction with parents. It is concluded that an association between some aspect of squab's interaction with seed and a parentally provided unconditioned stimulus is sufficient for normal pecking ot develop. The nature of these associations and their contribution to the ontogeny of independent feeding are discussed.

ISSN:0012-1630    

DOI:10.1002/dev.420180602

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

年代:1985

数据来源: WILEY

摘要:

AbstractInnate susceptibility to audiogenic seizures develops and declines at varying rates and ages, depending upon genotype and environmental conditions. Auditory dysfunctions have been experimentally produced which induce susceptibility in otherwise nonsusceptible mouse strains. In order to more closely correlate cochlear functions and audiogenic seizures in genetically susceptible mice, both measures were obtained from LP/J mice, at ages ranging from 8 to 120 days. Susceptibility to sound‐produced convulsions was first noted at 12 days, was maximal from 18 to 32 days, declined rapidly by 40 days, and disappeared by 120 days of age. Cochlear nerve‐evoked potential thresholds were very high at 12 days, were lowest between 18 and 32 days and increased thereafter. The correlation between susceptibility and cochlear thresholds was greatest for high frequencies (r= −.93), intermediate for midfrequency (r= −.77), and poorest for low frequencies (r= −.56). It was concluded that either genetic or environmental factors which produce an intermediate level of high frequency cochlear damage in the young mouse will produce susceptibility to audiogenic

ISSN:0012-1630    

DOI:10.1002/dev.420180603

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

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper reports changes in maternal behavior of rats following progestin treatment of the neonates. There have been recent reports that hormonial treatment of pups can alter maternal behavior, particularly licking of pups, and that such effects might have implication for the later development of those pups. Accordingly, the major objective of the experiments described was to test the hypothesis that the effects of neonatal progestins on later behavioral development that we have previously described (Birke&Sadler, 1983; 1984) might in part be mediated by changes in maternal behavior. This was done by investigating the behavior of dams, including pup‐directed behavior, following the hormone treatments that we have used previously. In the first experiment, medroxyprogesterone acetate (MPA), given via maternal milk, was found to increase rates of pup licking by dams. In the second experiment, anogenital licking was increased to litters containing pups that had received either MPA or progesterone by direct injection. No significant changes in licking following pup treatment with the antiserum to progesterone were observed, however. The results are discussed in relation to our previous work on progestin effects on later behavior, and in relation to the suggestion that hormonal effects on sexually dimorphic behaviors might, at least partly, be mediated through interactions with the mother during the neonatal perio

ISSN:0012-1630    

DOI:10.1002/dev.420180604

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

年代:1985

数据来源: WILEY

摘要:

AbstractShock‐induced aggressive behavior is absent or very weak in C57BL/6 mice at the age of 12 weeks, increases at the age of 16 weeks and reaches the highest levels at the age of 20 weeks. This age‐dependent increase of aggressive responses is absent in BALB/c and DBA/2 mice at the three ages examined in our experiments. Social isolation induces a clear age‐dependent increase of aggressive behavior in BALB/c and DBA/2 mice (the highest level being evident at 20 weeks of age) but not in C57BL/6 mice which are characterized by the lowest or absence of aggressive responses. These results are discussed in terms of the role of developmental and genetic factors in the expression of shock‐ and isolation‐induced aggressive behavior in the laborat

ISSN:0012-1630    

DOI:10.1002/dev.420180605

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

年代:1985

数据来源: WILEY

摘要:

AbstractYoung rats with lesions to either the globus pallidus, substantia nigra, median raphe, or pontine reticular formation have previously been reported to be deficient in learning a wide variety of laboratory tasks. In the current study, weanling rats subjected to one of these lesions were rested for three weeks, then examined for acquisition and extinction of a water‐motivated straight alley task, and finally tested on luminous flux discriminations of increasing difficulty. All brain‐damaged groups were slower than the controls in extinguishing the alley task and only the median raphe group failed to show an impairment on the discrimination problems. These results and others suggest that the foregoing lesions produce deficits in inhibitory and attentional processes. The possibility is discussed that young rats bearing these lesions might serve as a model for the investigation of the neurobiological and cognitive disturbances underlying certain classes of mental retardation in child

ISSN:0012-1630    

DOI:10.1002/dev.420180606

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn humans, a dominant somatosensory consequence of extensive unilateral neocortex damage is “simultaneous extinction,” which is an interhemispheric perceptual interaction that is operationally distinguishable from neglect. A tactile stimulus presented on the contralateral side of the body is detected when presented singly, but is completely masked during bilateral stimulation. Analogous tests designed to calibrate somatosensory asymmetries in rats were used to determine the long‐term effects of hemidecortication sustained on postnatal Day 1. These data were compared with that observed in adult operated rats at a comparable postoperative period. In one respect the neonatal brain was more vulnerable than the adult brain. That is, unlike adult operated rats which were tested at 3 postoperative months, a sensory asymmetry appeared to be permanent in the neonatally operated rats, at least for the duration of testing (3–9 months). Further analysis suggested that in another way the neonates were more resistant to the effects of hemidecortication than were the adults. Neonatally operated rats appeared to be capable of processing input from both sides of the body simultaneously, even during markedly asymmetrical input. In other words, the early occurrence of brain damage may have spared them from a condition reminiscent of “simultaneous extinction.” Finally, the adult operated and neonatally operated rats both displayed a subtle motor abnormality. Thus, depending on the test used, the neonatal operation yielded more severe, less severe, or comparable behavi

ISSN:0012-1630    

DOI:10.1002/dev.420180607

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

年代:1985

数据来源: WILEY

摘要:

AbstractFollowing placement into a test cage filled with pine shavings, a litter of 7–8 golden hamster pups (aged 3–18 days postnatal: P3‐18) initially displays a period of locomotion which ends reliably in huddling. The latency to establish a huddle (i.e., the duration of locomotion) is significantly longer in the presence of novel odors (fresh or lemon shavings) than more familiar odors (slightly soiled fresh or lemon shavings) but only in pups aged P12 or older. Pups aged P9 or younger do not locomote differentially in the presence of novel or familiar odors. This age difference represents the emergence of olfactory exploration in hamsters between P9 and P12. Exploration of novel odors interferes with initial attempts to establish a single huddle site by a litter, but does not preclude the ultimate aggregation of all pups at a single site as guided by conspecific odors and possibly thermotactile cues as well. Such shifts in the control of behavior by non‐nest and nest‐related, conspecific stimuli correspond well with the first occurrence of nest exits at P11‐12 (e.g., Dieterlen, 1959) coupled with the persistent return of hamster pups to the maternal nest for as long as it is maintained (Ro

ISSN:0012-1630    

DOI:10.1002/dev.420180608

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

年代:1985

数据来源: WILEY

摘要:

AbstractA U‐shaped function of behavioral growth characterizes the early ontogeny of face grooming in mice. In the first few postnatal days (0–100 hr), mice groom their face by using temporally isolated strokes, or bouts of strokes, which vary in amplitude and symmetry. Later on (100–200 hr), bouts disappear, asymmetry is eliminated, and the amplitude of strokes is gradually restricted; the infants engage in stereotyped, double‐handed, temporally isolated strokes. Finally (200–300 hr), bouts reappear, including both short and long, symmetrical and asymmetrical, strokes. These changes, are accompanied by unidirectional changes such as an increasing participation of the trunk, the neck, and the head in grooming, which lead to the flexible organization of face grooming seen in adults. Instead of describing development in terms of emerging unitary “acts,” we have recorded from high‐speed films three simultaneous aspects of movement: the movements of the separate limb and body segments, the resultant paths which are traced by the forepaws, and the paths of contact which are traced on the face. This method of description disclosed (a) reversible changes, and (b) a change in the relative stability of each of these aspects of face grooming, in the course of

ISSN:0012-1630    

DOI:10.1002/dev.420180609

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

年代:1985

数据来源: WILEY

摘要:

AbstractPhasic changes in heart rate were used to evaluate sensory reactivity and habituation in 5‐ and 12‐day‐old normal and decerebrate rats. Twenty‐four and forty‐eight hours after thalamic transection, temporally paired auditory or vibrotactile stimuli were repeatedly presented in a sensory disparity paradigm. While tone stimuli failed to evoke consistent cardiac change, vibrotactile stimuli produced cardiac decelerations, characteristic of the orienting response, in all subject groups. The magnitude of this response was comparable in both normal and decerebrate subjects at 5 days of age, but demonstrated a more notable increase with age in the normal subjects. Habituation of the cardiac response was apparent in all groups, and was not significantly different in the normal and decerebrate subjects. No consistent responses were apparent in any group to the unexpected omission of the second stimulus of the pair. Results indicate that orienting and habituation processes can persist in the absence of the cerebral hemispheres and support the view that lower levels of the neuraxis are capable of mediating a range of adaptive

ISSN:0012-1630    

DOI:10.1002/dev.420180610

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn three experiments the specificity of an effective reactivation stimulus, or reminder, was examined. Two weeks after learning to produce movement in a crib mobile by footkicking, 3‐month‐old human infants showed no retention of the response‐reinforcer contingency. A reactivation procedure 24 hours prior to the long‐term retention test was effective if the reminder was a brief noncontingent exposure to the original 5‐component training mobile or a mobile containing one novel substitution. When more than one novel component were substituted into the original mobile, the reminder was ineffective. This was predicted by the discrimination function 24 hours following training. A reminder containing only a single familiar (predictive) component and four novel ones was also moderately effective. In subsequent studies, we explored different interpretations of the reminder specificity effect. We hypothesize that reminder specificity is of particular adaptive value for developing organisms in providing a buffer against memory retrieval in inappropriate

ISSN:0012-1630    

DOI:10.1002/dev.420180611

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

年代:1985

数据来源: WILEY