bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retained elements of early avoidance training and relearning of forgotten operants
Authors: Sussman Paul S. , Ferguson H. Bruce 
Published: January 2005

AbstractIn a series of 7 experiments we investigated the possibility that juvenile rats show long‐term retention for aspects of early avoidance training and that these retained elements serve to reinforce relearning of the forgotten operants. Rats trained in active or passive avoidance at 23–25 days of age demonstrated the typical juvenile forgetting effect relative to adults after a 28‐day interval. However, both juveniles and adults demonstrated marked reductions in locomotor activity prior to retraining which were specific to the apparatus and not dependent on the opportunity to perform an operant during initial training. Juvenile animals given a reminder exposure plus footshock 27 days after training, then single daily nonshock trials (Days 28–30), showed decreasing crossover latencies across days if trained in active avoidance and increasing latencies if trained in passive avoidance. This reappearance of task‐appropriate crossover latencies was evident in previously trained juveniles only. Finally, young animals' demonstrated change in crossover latency is associated with subsequent superior acquisition performance, and this change depends upon the presentation of the test trials for its appearance. We suggest that the amelioration of “infantile amnesia” associated with the present procedures is a learning process motivated by Pavlovian components of training which are retained well, by juveniles and adults alike, over intervals typical of ontogeny of memory research.
Models of infantile malnutrition in rats: Effects on maternal behavior
Authors: Crnic Linda S. 
Published: January 2005

AbstractThe effects of 6 commonly used methods for producing malnutrition in suckling rats upon the behavior of their dams were examined. In these methods, (1) large litters were fostered on the dams; (2) dams were fed low‐protein diets; (3) dams were fed an inadequate amount of a good quality diet; (4) pups were removed from the dams and kept with a nonlactating female for half of the day; (5) pups were removed from the dams and kept in an incubator for half of the day; or (6) some of the dams' teats were destroyed. Dams that were themselves food deprived showed a shift from resting to exploratory behaviors with some indication of increased attention to the pups compared to controls. Dams whose pups were starved but that were well fed themselves showed lower levels of resting and higher levels of attention to pups but no elevation in exploratory activity. Although the long‐term significance of the behavioral changes of the dams is not known, the immediate effect was to minimize the impact of the experimenter's manipulations on the metabolic energy available to the pups for growth and development.
Dietary influences on the development of sucrose acceptability in rats
Authors: Bertino Mary , Wehmer Francine 
Published: January 2005

AbstractWeanling rats were placed on a high‐fat diet or chow. Beginning at 5 weeks of age, they were tested for acceptability of 4 sucrose solutions of different concentrations once a week until they showed the previously established adult pattern of acceptability. Subjects on the chow diet showed a gradual transition from a juvenile to adult pattern of acceptability, that is, a progressive downward shift in the concentration of solution that is most acceptable. Subjects on the high‐fat diets never showed the adult pattern but continued to display a juvenile pattern of acceptability throughout the experiment. The data obtained from the subjects on the high‐fat diets are similar to those on taste preferences in obese humans.
Canalization of arousal in the preweanling rat: Effects of amphetamine on aggregation with surrogate stimuli
Authors: Campbell Byron A. , Raskin Lisa A. 
Published: January 2005

AbstractPreweanling rats, 15 days of age, were placed in an unfamiliar cage containing 1 of a variety of surrogate conspecific stimuli. The surrogate stimuli consisted of a rat‐sized aluminum tube covered with soft fluffy synthetic fur, a tanned rat pelt, felt, and an aluminum sheet. The surrogate was either maintained at ambient temperature of heated to body surface temperature (37°C). The 1st experiment revealed that both furriness (length and softness of fur) and temperature of the surrogate stimulus are important determinants of conspecific aggregation (huddling). The 2nd experiment demonstrated that preference for the soft, fluffy surrogate was not mediated by temperature conservation by showing that the same huddling behavior was obtained when ambient temperature was raised to thermoneutrality (33°C). The final experiment demonstrated that amphetamine restricted the range of surrogate stimuli that elicited huddling in the preweanling rat. The finding that amphetamine produces a steeper generalization gradient of approach to surrogate stimuli further confirms our previous hypothesis that amphetamine canalizes arousal toward salient environmental stimuli. These findings have implications for the use of amphetamines to treat hyperkinetic children.
Adjustment of weanling and adolescent rats to a reward condition requiring slow responding
Authors: Chen Jaw‐Sy , Gross Keith , Stanton Mark , Amsel Abram 
Published: January 2005

AbstractThe effects of a schedule of discontinuously negatively correlated reinforcement (DNC), in which only approach responses that take 5 sec or longer are reinforced, were studied in weanling rats that began training at 18 days of age and adolescents that began training at 60 days. Yoked partially reinforced subjects (PRF) received rewards on the same trials as corresponding DNC subjects of the same age, whereas continuously reinforced subjects (CRF) were rewarded on all trials. At the end of DNC training (210 trials), the older but not the younger DNC subjects were running slower than their yoked‐PRF controls. The results are consistent with the development of inhibition and suppression related to the developing brain, particularly the hippocampus.
Receiving severe aggression correlates with fetal gender in pregnant pigtailed monkeys
Authors: Sackett Gene P. 
Published: January 2005

AbstractPregnant females were severely bitten in 220 of 2,822 conceptions among pigtail macaques living in harem groups. These pregnancies yielded 58.6% female offspring compared with 48.5% for nonbitten pregnant animals. The fetal gender difference occurred only after midterm, reaching a peak of 70% female fetuses in the 4th gestational month. Fetal gender thus appeared to influence maternal behavior, appearance, or physiology in some way detectable to other monkeys with the consequence of altering risk for receiving severe aggression.
Volume discrimination learning in golden hamsters: Effects of the structure of complex rearing cages
Authors: Thinus‐Blanc Catherine 
Published: January 2005

AbstractGolden hamsters (Mesocricetus auratus) were reared from birth to adulthood in a spatially diversified situation (EG); their performances were compared with those of other hamsters housed in standard laboratory cages (SG). The task was to discriminate between 2 cubic volumes of different sizes followed by various test situations designed to define the respective parts played by the 3 spatial dimensions during perception. The results show that surfaces of volumes were mainly taken into account by EG subjects whereas width, alone, was used by the SG animals.
Single‐dose tolerance to morphine‐induced analgesic and hypoactive effects in infant rats
Authors: Bardo Michael T. , Hughes Richard A. 
Published: January 2005

AbstractA single injection of morphine or isotonic saline was administered to rats at either 1, 5, 9, or 13 days of age. At 26–29 days of age, animals were tested for pain responsivity and activity following either morphine (5 mg/kg) or saline. Animals which received morphine at 1 day of age displayed tolerance at 26 days of age, whereas animals which received morphine at either 5, 9, or 13 days of age failed to display tolerance. This age‐dependent change in susceptibility to single‐dose morphine tolerance may involve alterations in opiate receptor ontogeny.
Motor asymmetries in preterm infants: Effects of prematurity and illness
Authors: Fox Nathan , Lewis Michael 
Published: January 2005

AbstractTwo types of motor asymmetry, postural asymmetry and lateral head turning, were assessed in 3 groups of preterm infants, one of which had experienced respiratory distress syndrome (RDS) in the postnatal period. Results reveal that maintenance of a right postural asymmetry is present as early as 34 weeks conceptional age and is not disrupted by postnatal illness. Lateral head turning after midline placement was evident as early as 36 weeks conceptional age but was disrupted by physiologic condition. Infants who had experienced RDS had poor muscle tonus and did not assume the head right position even at 39 weeks conceptional age. These data argue that lateral responding may be affected by illness and that studies of preterm populations must evaluate postnatal medical condition when assessing both the short‐ and long‐term outcomes of lateral asymmetries.
A quantitative analysis of the feeding behavior of suckling rabbits
Authors: Drewett R. F. , Kendrick K. M. , Sanders D. J. , Trew A. M. 
Published: January 2005

AbstractThree experiments are reported on the feeding behavior of suckling rabbits (“kittens”). In the 1st the latency with which the kittens attached to the nipple, and then left the nipple, was determined. Attachment was very rapid and wholly reliable: on the 80 tests the nipple was seized in every case in under 9 sec, and on 67 of these in less than 3 sec. The kittens also invariably left the nipple within the next minute. If the kittens were 5 or 10 days old speed of attachment was unaffected by the presence or absence of saliva on the nipple, but 15‐ and 20‐day‐old kittens seized the sucked nipples more rapidly than the unsucked nipples. In a 2nd experiment with 12‐day‐old kittens, washing the nipple with solvents did not affect speed of attachment; nor did saliva. The results show that suckling rabbits, in contrast to rat pups, are not heavily dependent on saliva cues. In the 3rd experiment both attachment latency and milk intake were shown to be affected by an internal stimulus, a gastric load of .9% saline, 5 g/25 g body weight: attachment latency was significantly increased and milk intake reduced by 75%.
Effects of early social experience on activity and object investigation in the ferret
Authors: Chivers Susan M. , Einon Dorothy F. 
Published: January 2005

AbstractEarlier experiments have shown that many of the effects of early social isolation in the rat may be due to deprivation of social play. The isolated ferret, like the isolated rat, is hyperactive; further‐more, its hyperactivity appears to be related to deprivation of social play. However, the relationship between object investigation and social rearing is more complex in the ferret than it is in the rat.
Selective resistance to approach: A precursor to fear responses to an alarm call in great tit nestlings Parus major
Authors: Rydéan Olof O. 
Published: January 2005

AbstractThe reactions of 10‐day‐old great tit nestlings to 3 auditory stimuli were studied. The stimuli, presented on a series of feeding occasions, were (1) the species' “seeet” alarm call, (2) a song strophe of the great tit, and (3) a song strophe of the tree‐creeper (Certhia familiaris). In contrast to earlier findings in studies of older nestlings, these younger nestlings did not respond to the alarm call with cessation of begging. However, a significant differential effect of the alarm call was demonstrated when the conditioning rates for the nestlings' begging response to each of the 3 stimuli were determined. Thus, conditioning was significantly slower to the alarm call than to the other stimuli. The results agree with the general conception that responses to species‐specific calls develop gradually during early ontogenesis. Thus fear responses to the alarm call, such as cessation of begging and “freezing,” which are elicited in newly fledged young, are preceded by weaker aversive tendencies that are not obvious from observations of the nestlings' behavior in nature. It is suggested that the nestlings' exposure to contrasting auditory stimulation–their own begging call and the parental feeding call–constitutes the experiential base for withdrawal responses to the “seeet” call.
Control of sleep‐wake states in the infant rat by features of the mother‐infant relationship
Authors: Hofer Myron A. , Shair Harry 
Published: January 2005

AbstractA series of experiments in 2 strains of Wistar rats explored which aspects of maternal separation were responsible for the sleep disturbance of the young. Neither their own mother, after mammary duct ligation, nor constant intragastric infusion of nutrient during the day of separation were found to ameliorate significantly the changes in sleep‐wake state organization. However, a periodic nutrient delivery schedule and a formula closely resembling rat milk each ameliorated, and together entirely prevented, the sleep‐wake disturbance. Decreased ambient temperature during separation tended to exaggerate the disturbance and periodic tactile‐vestibular stimulation tended to reduce it. These findings suggest that the infant rat's normal sleep‐wake pattern is maintained by the thythmicity and composition of the milk delivered to it by its mother, although her warmth and behavioral interaction with it may play subsidiary roles. Separation produces its effects by removing these regulating features of the relationship.
Environmental and biologic interactions on behavior: Effects of artificial rearing in rat pups treated with 6‐hydroxydopamine
Authors: Goldenring James R. , Shaywitz Bennett A. , Wool Robert S. , Batter David K. , Anderson George M. , Cohen Donald J. 
Published: January 2005

AbstractIn order to examine the impact of social environment on the development of motor activity and cognitive performance in rat pups treated with 6‐hydroxydopamine (6‐OHDA), we employed artificial rearing techniques pioneered by Hall. In contrast to 6‐OHDA‐treated mother‐reared pups which exhibit an increase in activity during their first postnatal month, 6‐OHDA‐treated artificially reared animals fail to demonstrate this hyperactivity. The absence of hyperactivity in 6‐OHDA‐treated artificially reared pups may reflect the absence of isolation‐induced motor activity at the beginning of the test period. Both mother‐reared and artificially reared 6‐OHDA pups demonstrated impairment in shock escape and shock avoidance, suggesting that these deficits in maze performance were influenced by an inherent biological lesion following 6‐OHDA treatment while motor activity may depend, to a considerable extent, on environmental manipulations.
Effects of chronic crowding stress on midbrain development: Changes in dendritic spine density and morphology in jewel fish optic tectum
Authors: Wesley Burgess J. , Coss Richard G. 
Published: January 2005

AbstractThis study investigates the effects of a biologically relevant stressor, crowding, on the development of neurons in the major teleostean brain area, the optic tectum. Adult jewel fish were reared for approximately 4 years under conditions of moderate density (3.3 liter/fish), or under uncrowded control conditions (25 liter/fish). Quantitative morphometric measures of Golgi‐stained tissue were used to test whether long‐term crowding at moderate density produced developmental deficits lasting beyond the juvenile period. Chronic crowding did not affect body size or gross tectal growth. However, crowding significantly decreased the density of dendritic spine formation on apical dendrites of pyriform interneurons in the basal region of the tectum (stratum album centrale). Additionally, the shapes of spines on this segment of the apical dendrite were altered by crowding: relative frequencies of overall spine length and spine stem length changed significantly. These results are interpreted in the context of cytoarchitectural changes produced by more extreme developmental stressors in previous studies.
Short‐ and long‐term effects of various milk‐delivery contingencies on sucking and nipple attachment in rat pups
Authors: Brake Stephen C. , Sullivan Regina , Jayne Sager D. , Hofer Myron 
Published: January 2005

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 behavior.
“Conservations” with a chimpanzee
Authors: Muncer Steven J. 
Published: January 2005

AbstractTwo chimpanzees (Pan tryglodytes), Fanny and Jane, were presented with liquid and number conservation problems. One chimpanzee, Jane, was successful in solving both sets of problems in that she was not distracted by irrelevant transformations, being influenced only by changes in quantity. Her success appeared to be based on the ability to make inferences rather than on simple perceptual judgement of the final comparison. The results are compared and contrasted with those of Premack, in G. Woodruff, D. Premack, and K. Kennel [(1978). Conservation of liquid and solid quantity by the chimpanzee. Science, 202:99–994] and J. Mehler and T. G. Bever [(1967). Cognitive capacity of very young children. Science, 158:141–142; (1968). Quantification, conservation and nativism. Science, 162:979–981], and it is suggested that there may be a similarity of conservation development between chimpanzees and man.
Periadolescence: Age‐dependent behavior and psychopharmacological responsivity in rats
Authors: Spear Linda Patia , Brake Stephen C. 
Published: January 2005

AbstractThe behavior and psychopharmacological sensitivity of periadolescent rats are examined in this review. Periadolescent rats are hyperactive and engage in more conspecific play behavior than younger or older rats. When compared with other‐aged rats, periadolescents exhibit enhanced performance in simple active‐avoidance learning tasks, but perform poorly in more complex appetitive and avoidance learning tasks in which increases in locomotor activity do not improve performance, perhaps as a result of age‐specific alterations in selective attention or stimulus processing. Such behavioral “anomalies” of periadolescent animals observed in traditional laboratory situations may be in some way adaptive when considered in the context of the animals' natural habitat. In terms of psychopharmacological responsiveness, periadolescent rats, when compared with younger or older animals, are less sensitive to catecholaminergic agonists but are more responsive to the catecholaminergic antagonist haloperidol. This pattern of psychopharmacological sensitivity suggests that the catecholaminergic systems may be temporarily hyposensitive during the periadolescent period. Evidence is presented that a negative feed‐back system in the form of dopamine autoreceptors may become functionally mature in mesolimbic brain regions during the periadolescent period. The possibility is presented that maturation of these self‐inhibitory autoreceptors might result in a temporary decrease in the efficacy of mesolimbic dopamine projections, perhaps contributing to the psychopharmacological and behavioral characteristics of periadolescent animals. In support of this suggestion, evidence is reviewed indicating that the behavior of adult animals with lesions of the ventral tegmental area, a region containing cell bodies from which these mesolimbic dopaminergic projections originate, resembles that of periadolescent rats.
The influence of siblings on the development of sexual preferences of male zebra finches
Authors: Kruijt J. P. , Ten Cate C. J. , Meeuwissen G. B. 
Published: January 2005

AbstractBroods of young zebra finches were either raised by their own species or cross‐fostered by Bengalese finches. Both were isolated visually from other birds at the age of 2 months. Sexual preferences of males, were examined at maturity, in a choice between 1 zebra finch female and 1 Bengalese finch female, by measuring the number of song strophes directed at each. Males raised by their own species sang exclusively for the zebra finch female. Cross‐fostered males raised without siblings or with only 1 sibling sang exclusively for the Bengalese finch female. A large number of cross‐fostered males raised with 2–4 siblings showed at least 5% singing for the zebra finch female, and a small number did so predominantly. It is concluded the under the conditions of these experiments, the development of sexual preferences of zebra finch males is affected by both parental and sibling influences. It is possible that the earlier evidence for a predisposition to respond to conspecifics put forward by Immelmann could be explained by hitherto uncontrolled differences in experience.
Alleviation of infantile amnesia in rats by internal and external contextual cues
Authors: Richardson Rick , Riccio David C. , Axiotis Renee 
Published: January 2005

AbstractA previous study [Richardson, R., Riccio, D. C., and Jonke, T. (1983). Alleviation of infantile amenesia in rats by means of a pharmacological contextual state. Devel. Psychobiol., 16: 511–518] found that ontogenetic forgetting (“infantile amnesia”) in rats was attenuated by a “contextual matching” manipulation: Subjects trained in a distinct pharmacological state and tested in that state retained learned fear better than saline controls. To determine whether improved retention could be obtained with salient but nonpharmacological contexts, two experiments were conducted employing fear conditioning in preweanling rats. In Experiment 1, an internal context (illness induced by lithium chloride) present at training and testing reduced infantile forgetting. In experiment 2, matching an exteroceptive context (home nest shavings) at training and testing was also found to be sufficient to alleviate infantile amnesia. In both experiments, retention was not improved in controls exposed to the context at training only or testing only, indicating that the contextual effect is not on acquisition or retrieval processes per se. These findings provide indirect support for views that emphasize the role of contextual cues in retrieval (Spear, 1978). In addition, they indicate that contextual matching is not limited to a state dependent drug, but may include a wide range of “distinctive” stimuli.