bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experience with younger siblings facilitates maternal responsiveness in pubertal norway rats
Authors: Stern Judith M. , Rogers Louise 
Published: January 2005

AbstractThe latency of maternal behavior (MB) onset induced by cohabitation with pups (sensitization) increases in female and male Long‐Evans rats from 24 days of age (1–2 day latency) to 42 days of age (4–5 day latency). This decline in maternal responsiveness at Day 42 did not occur in 50% of rats (“responders”) which lived with their dam and younger siblings (conceived during the postpartum estrus) for either 4 or 11–18 days after their birth. In contrast to cessation of suckling at about Day 25 postpartum in the absence of a 2nd litter, when a 2nd litter was born >Day 26 or <Day 26 postpartum, suckling continued for a mean of 32 and 35.5 days, respectively (and up to Day 40). Also, time spent suckling during the 10 days following the birth of the 2nd litter was more than five times as great if the 2nd litter was born with little or no delay (Day 26). The offspring from the 1st litter spent about 80% of the diurnal observation time in proximity to the dam and younger siblings, and instances of nurturance (retrieving, crouching, licking) toward the young littermates were observed. However, the only dam‐litter interaction significantly related to subsequent maternal responsiveness by 1st litter offspring was a positive relation between the prior incidence of aggression by mothers towards juveniles and sensitization latency.
Effects of lateral displacement of the visual field on the development of visual‐motor abilities in cats
Authors: Hendy Helen M. , Riesen Austin H. 
Published: January 2005

AbstractIn this study, we test the flexibility of the cat's visual system by examining the visual‐motor effects of both moderate and extreme lateral displacement of the visual field. While being reared with masks that provided either 0, 15, or 30 diopters lateral displacement of the visual field, 23 kittens received 3 tests of visual‐motor abilities: a visual cliff task, a visual guiding task, and a five‐alley choice task. No significant differences were found among the 0, 15, or 30 diopter displacement groups for any of the 3 tasks for either the total number of days to reach criterion performance, for the development of performance over time during the early days of testing, or for the development over time to criterion performance. After reaching criterion, kittens readapted to transposed conditions of displacement. The group changed 30 diopters did significantly worse than the group changed 15 diopters, both in error scores and in time to criterion performance. The present results with kittens are compared to those of other investigators and suggestions are made for future research.
Metaphors for development: How important are experiences early in life?
Authors: Klopfer Peter 
Published: January 2005

AbstractThe many students of development have held rather diverse views on the importance of early experience. Some gave early experiences great prominence (e.g., Freud and his followers, Kuo, 1967), while others largely rejected the pivotal importance of particular early events (e.g., Thorndike), and yet others took a more eclectic tack: Some events in certain species but not all events or in all cases (e.g., Hinde, 1974, Lehrman, 1970). The extremes among the prevailing views are often characterized metaphorically. I propose to do this, then to examine the kinds of situations the metaphors describe, and inquire into their generality and usefulness. Clearly this runs the risk of undue simplification, but there is, I believe merit in occasionally ignoring some of the subtleties that usually must concern us.
Body scale and the development of prehension
Authors: Newell K. M. , Scully D. M. , Tenenbaum F. , Hardiman S. 
Published: January 2005

AbstractThis study examined whether common dimensionless ratios define the critical point in the shifts in the grip coordination pattern of preschoolers and adults engaged in a displacement grasping activity with cubes that varied in object size. The findings indicated that there was an interaction between task constraints and organismic constraints in determining the grasping pattern utilized. However, when the object size is scaled to hand size there are common dimensionless rations that correspond to the grasping patterns and the limb orientations employed across the age range utilized. Furthermore, 5 grip configurations accounted for the majority of grip variance in both age groups. The findings suggest a strong role for the impact of body scale on the development of coordination and provide preliminary evidence for the view that the development of prehension is a reflection of the constraints imposed on action.
Maternal behavior of SHR rats and its relationship to offspring blood pressures
Authors: Myers Michael M. , Brunelli Susan A. , Squire Jonathan M. , Shindeldecker Richard D. , Hofer Myron A. 
Published: January 2005

AbstractIn Part I of this study maternal behavior of 15 spontaneously hypertensive (SHR) and 11 Wistar‐Kyoto (WKY) rat mothers was recorded throughout the preweaning period. SHR mothers were observed: 1) in arched‐ and blanket‐nursing postures more often, and in passive‐nursing posture less often, 2) licking their pups more often, and 3) resting less often. Further, SHR mothers retrieved their pups more quickly than did WKY. In the second part of this study we found that a composite maternal behavior score, derived from summing occurrences of motheripup contact, arched‐nursing, and puplicking, was positively correlated with the offspring blood pressures. This relationship, which accounted for 43.5% of the variance in adult blood pressure, suggests that certain types of interactions between mothers and their pups may contribute to individual differences in cardiovascular system development.
Relationships between maternal behavior of SHR and WKY dams and adult blood pressures of cross‐fostered F1 pups
Authors: Myers Michel M. , Brunelli Susan A. , Shair Harry N. , Squire Jonathan M. , Hofer Myron A. 
Published: January 2005

AbstractIn this experiment SHR and WKY dams reared genetically identical F1 pups derived from SHR X WKY matings. We found that a composite maternal behavior score was positively correlated with adult blood pressures of the fostered offspring. This replicated a similar finding from our previous study in which SHR and WKY mothers reared their own pups. Unlike this previous Study, WKY dams rearing F1 pups exhibited maternal behavior patterns similar to SHR dams. Finally, we found their was no effect of the strain of foster mother upon adult blood pressures of the F1 offspring. These results indicate that some aspects of maternal behavior may change as a function of pup characteristics, and support our hypothesis that the cardiovascular system may be shaped by experiences of early life which are embedded in mother/young behavioral interactions.
Male rat pups are more hesitant to urinate in response to anogenital stimulation than are their female sibs
Authors: Clark Mertice M. , Galef Bennett G. 
Published: January 2005

AbstractMale rat pups required more anogenital stimulation before they began to urinate than did their sisters and males produced more urine than their female sibs during a fixed period of anogenital stimulation. These findings are interpreted as consistent with the view that neonatal mammals can manipulate the behavior of their dams.
The role of homecage environmental stimuli in the facilitation of shock‐motivated spatial discrimination learning in rat pups
Authors: Misanin James R. , Hinderliter Charles F. 
Published: January 2005

AbstractIn three experiments we examined the role of homecage environmental stimuli on learning an aversively motivated spatial discrimination task in 11‐day‐old rats. Varying the presence and absence of nest shavings in the correct and incorrect arms of a T‐maze in Experiment 1 revealed that nest shavings had both nondirective facilitation and approach‐eliciting properties. Training the 11‐day‐old rats in the presence or absence of shavings over three daily sessions and comparing their performance on the third day of training with that of a maturation control in Experiment 2 indicated that there is a residual training effect of the approach‐eliciting property of nest shavings on shock‐escape behavior. In Experiment 3, using nest shavings either as an irrelevant stimulus or as a redundant relevant cue in an aversively motivated T‐maze reversal task suggested that 11‐day‐old rats acquire the discrimination task using non‐nest spatial or directional cues as well as those provided by nest shavings. Overall, these results suggest that nest shavings introduced into aversively motivated tasks create a learning environment comparable to that of appetitively motivated instrumental tasks utilizing suckling from an anesthetized dam as a reinforcer.
Measuring rates of sexual development in female Mongolian gerbils
Authors: Clark Mertice M. , Galef Bennett G. 
Published: January 2005

AbstractIn previous experiments, we have shown that age at vaginal introitus predicts adult patterns of reproductive, maternal, and aggressive behavior of female Mongolian gerbils. In the present series of studies, we explored the relationship in gerbils between age at vaginal patency and three other indices of rate of female sexual development: ovarian weight, occurrence of vaginal estrus, and onset of attractiveness to males. We found that female gerbils, classified on the basis of their ages at vaginal introitus as early‐maturing: (a) exhibited greater ovarian weights throughout development than did their late‐maturing, female sibs; (b) exhibited estrus and Diestrus I stage vaginal smears and, by inference, ovulation at an earlier age than did late‐maturing females; and (c) elicited mounting by males at an earlier mean age than did late‐maturing females. The data were consistent with the hypothesis that age at vaginal introitus is a reliable indicator of rate of sexual development in female Mongolian gerbils.
The quantitative relationship between nutritional effects on preweaning growth and behavioral development in mice
Authors: Wainwright Patricia , Pelkman Christine , Wahlsten Douglas 
Published: January 2005

AbstractOur objective was to establish whether nutritional effects on the behavioral development of preweaning mouse pups were linearly related to effects on body and brain growth or whether there was a threshold effect, with behavior being affected only by nutritional extremes. We also used a standardized scale of development to compare the relative magnitude of such effects on morphological and behavioral measures. The level of nutrient availability was manipulated continuously by rearing the pups in litter sizes ranging from 3 to 12. On Day 32 post‐conception, measures were taken of body weight, brain weight, thickness of the cerebellar external granular layer (EGL), and behavioral development. The relationship between litter size and body weight, brain weight, and behavioral development was best described by a linear regression model; no threshold effect was apparent. By comparing measures on animals from different litter sizes at the same age (32 days) to standard developmental curves over a wide range of ages, we found that for every additional pup in a litter, body growth was retarded by the equivalent of 1.28 days, brain weight by 0.44 day, and behavioral development by 0.07 day.Although the variation in nutrient availability provided by this range of litter sizes does result in a linear relationship between growth and behavioral development, there is nevertheless considerable sparing of function.
Dopamine D‐2 receptor mediation of response suppression learning of young rats
Authors: McDougall Sanders A. , Nonneman Arthur J. 
Published: January 2005

AbstractIn three experiments, the effects of augmenting or blocking dopamine (DA) D‐2 receptor activity on the ontogeny of response suppression learning of preweanling rat pups were determined. In the intial experiment, rat pups were trained to traverse a straight alley for nipple attachment to an anesthetized dam. When footshock (0.2 mA, 0.5 sec) was made contingent on responding, younger (11‐and 13‐day‐olds) rat pups were deficient to older (17‐and 19‐day‐olds) pups at withholding punished responding. In the subsequent experiments, response suppression learning was assessed after injecting 11‐and 17‐day‐old rat pups with the specific DA D‐2 agonist, LY 171555 (0.005−, 0.01−, and 0.1−mg/kg, i.p.), or the specific DA D‐2 antagonist, sulpiride (5.0−, 15.0−, and 50.0−mg/kg, i.p.). LY 171555 enhanced the punished responding of both the 11‐and 17‐day‐old rat pups; whereas, sulpiride increased the punished responding of the 17‐, but not the 11‐day‐olds. In four additional experiments, the effects of LY 171555 and sulpiride on the locomotor activity, nociception, and reinforcement processes of 17‐day‐old rat pups was assessed. Rat pups given LY 171555 (0.01 mg/kg, i.p.)exhibited enhanced locomotor activity and a trend towards hyperanalgesia using a hot plate task. Sulpiride (15.0 mg/kg, i.p.) completely antagonized LY 171555′s activity enhancing effects and had hyperalgesic properties. In two experiments, sulpiride did not affect the nonpunished appetitive responding of the 17‐day‐olds; whereas, haloperidol‐treated pups responded on fewer reinforced trials than did saline‐treated pups. Therefore, these results indicate that the response suppression learning of 17‐day‐old rat pups is mediated, at least partially, by a DA D‐2 receptor system, and that D‐2 receptors are also involved in the locomotor activity and nociceptive responses of young rat pups.
Nursing interaction of Wistar rats is modified by prior experience of altered nursing bout length
Authors: Hofer Myron A. , Zmitrovich Ann , Shair Harry N. 
Published: January 2005

AbstractWe tested the capacity of 2 week postpartum Wistar rat litters and their dams to adapt to experimental shortening and lengthening of the time available for nursing while maintaining the frequency of bouts constant, using manual transfer between cage compartments. In 8‐hr and 24‐hr experiments, the short bout group (10 min/hr) gradually came to show normal litter weight gain, short latency milk ejections, and increased high arched nursing position, while the 40‐min/hr group showed increased latency to attachment and longer latency to ME compared to the 20 min/hr control group. Pup body temperature did not vary between groups. Although pups in the 10‐min group showed increased dam‐directed behaviors in the first 8h, this difference vanished thereafter. In a twenty‐fifth cycle, after dams and litters were exchanged, the prior experiences of the dams and not of the litters were found to determine the dynamics of milk exchange.
Rat pup isolation distress and the brain benzodiaze pine receptor
Authors: Insel Thomas R. , Gelhard Robert E. , Miller Leonard P. 
Published: January 2005

AbstractPharmacologic studies have demonstrated that benzodiazepines can modulate the ultrasonic vocalizations (USV) associated with social separation of rat pups. In this study, in vivo receptor autoradiography was used to determine if brain benzodiazepine receptors were functionally less available to bind an exogenous ligand during social separation. The labeled benzodiazepine receptor antagonist, 3H‐RO 15‐1788, was given to 10‐day‐old rat pups with varying schedules of social separation. In initial studies with homogenized and solubilized tissue, we found a 30% reduction in binding to cortex when pups were separated for 25 min beginning 5 min prior to tracer injection. In subsequent autoradiographic studies with this same separation schedule, the binding of 3H‐RO 15‐1788 was examined in 21 brain regions. Again binding was decreased in neocortex (frontal, motor, and somatosensory). In addition, we found significantly decreased binding in hippocampus, dentate gyrus, and superior and inferior colliculi. These same regions showed no alteration of in vitro binding of 3H‐RO 15‐1788. Therefore, these decreases in in vivo binding do not reflect changes in receptor number. The interpretation of decreased in vivo binding and implications of these results for defining the neural substrates of separation behavior are discussed.
Effect of maternal presence on the cardiac and behavioral responses to shock in rats as a function of age
Authors: Richardson Rick , Siegel Michael A. , Campbell Byron A. 
Published: January 2005

AbstractIn two experiments the effects of the presence of an anesthetized lactating dam on the developing rat's response to a series of midly painful shocks was examined. Both cardiac and behavioral responses to the shock stimulus were recorded. In the first experiment animals were tested at either 16, 20, or 24 days of age. The presence of the anesthetized dam markedly reduced the behavioral response to shock of the 16‐day‐old but not the older rats. A similar pattern of results was obtained with the shock‐elicited tachycardia. The second experiment replicated these results with the 16‐day‐old rat and also demonstrated that being shocked in the presence of a lactating dam influences the animal's reaction to a subsequent series of shocks given when it is alone. The results of these two experiments are discussed in terms of other studies that have examined the influence of maternal presence on the developing animal's response to stressful or painful stimuli.
Stimulus duration and repetition rate influence newborns' head orientation toward sound
Authors: Clarkson Marsha G. , Clifton Rachel K. , Swain Irina U. , Perris Eve E. 
Published: January 2005

AbstractThree experiments evaluated the effects of stimulus duration and repetition rate on newborns' head orientation responses. In Experiment 1, 28 infants turned toward a 20‐sec continuous rattle sound but not toward 14‐and 500‐msec rattle sounds. Signal energy as a possible explanation for the infants' difficulty orienting toward brief sounds was explored in Experiment 2. Twenty neonates did not turn toward a single 90 dB, 14‐msec rattle sound, although a longer duration (10 sec) sound containing less energy (70 dB) did elicit reliable head orientation. In Experiment 3, 16 neonates heard trains of repeated 14‐msec rattle sounds (2/sec, 1.3/sec, and 1/sec) lasting 10 sec as well as a 10‐sec continuous rattle sound. They turned toward the most rapidly repeating brief sound and the continuous one, while the slowly repeating sounds elicited little head movement in any direction. These results suggest that newborns' head orientation is selectively deficient for brief sounds, that the difficulty does not result from lessened energy in the brief sounds, and that the efficacy of repeated brief sounds depends upon their repetition rates.
Task constraints and infant grip configurations
Authors: Newell K. M. , Scully D. M. , McDonald P. V. , Baillargeon Renée 
Published: January 2005

AbstractThe prehensile grip configurations of infants aged 4 through 8 months were examined as they grasped objects that varied in size and shape. The findings revealed that infants as young as 4 months systematically differentiate grip configurations as a function of the object properties in essentially the same way that 8‐month‐old infants do. However, the younger 4‐month‐old infants predominantly used the haptic system in additional to the visual system for information pick‐up regarding object properties, whereas 8‐month‐old infants predominantly used information from the visual system alone to differentiate grip configurations according to the object properties. Infants apparently percive the same action‐relevent information through different emphases of the sensory modes to drive the action system with a similar grip configuration for a given object. It is proposed that the traditional description of an orderly sequence to the development of infant prehension (e.g., Halverson, 1931) is too conservative and inflexible to capture the functionally adaptive prehensile behavior of infants to changing task constraints.
Premature visual stimulation accelerates intersenory functioning in bobwhite quail neonates
Authors: Lickliter Robert 
Published: January 2005

AbstractRecent evidence from both altricial and precocial neonates suggests that premature stimulation of a later developing sensory system may alter the functioning of earlier developing sensory systems. The present study examined the influence of prenatal visual stimulation on postnatal auditory functioning in precocial bobwhite quail chicks. Hatchlings that experienced patterned light during the 24–36 hr prior to hatching did not exhibit a naive auditory preference for their species‐specfic maternal call at 24 hr or 48 hr following hatching, a reliable phenomenon in chicks not receiving embryonic visual stimulation. To examine whether this lack of responsiveness resulted from enhanced intersensory functioning, hatchlings were tested for preference for both auditory and visual features of the bobwhite hen. Results indicate that prematurely stimulated chicks require species‐typical auditory and visual stimulation earlier in postnatal development than do normally reared chicks to direct their filial behavior. These findings point to the importance of normally occurring developmental limitation of sensory input to early species‐typical sensory/perceptual organization.
Development of head position preference during early infancy: A longitudinal study in the daily life situation
Authors: Hopkins Brian , Lems Yvonne L. , Palthe Titia Van Wulfften , Hoeksma Jan , Kardaun Otto , Butterworth George 
Published: January 2005

AbstractWe studied developmental changes in supine head position preference in a group of 14 healthy full‐term infants from age 3 to 18 weeks. The infants assumed an initial head‐right position until 12 weeks. For the maintenace of a head position, a loglinear analysis revealed a developmental trend from and initial head orientation to the right to one with the head in the midline at around 12 weeks. The maintenance of a midline head position was preceded by a marked improvement in postural stabilization, defined as the ability to hold the head upright when seated in an infant chair. The relationship between head position preference and behavioral state changed with age: At 3 weeks all infants maintained the same position regardless of state, but by 18 weeks this situation held for only 64% of those who cried. The implications of these findings for the development of handedness are discussed.
A new method for delivering a taste without fluids to preterm and term infants
Authors: Maone Teresa R. , Mattes Richard D. , Bernbaum Judith C. , Beauchamp Gary K. 
Published: January 2005

AbstractA new method for administering a taste to preterm and term infants has been developed that does not necessitate the delivery of sapid solutions. Sucrose, a sugar that in solution was shown to potentiate sucking behavior, was embedded in gelatin‐based nipples that continuously release sweet taste when mouthed or sucked. The gelatin nipple and comparable latex nipples were adapted to measure sucking behavior and were tested in a within‐subject design. The gelatin nipples potentiated sucking in preterm and term infants by increasing the frequency and strength of the responses. Few sucking measures varied significantly for preterm and term infants. Those that did vary might be attributable to differences in physical stamina, rather than to orosensory orhedonic factors. It was concluded that the flavored gelatin nipple provides an effective method for studying taste in infants and offers the possibility of routine chemosensory stimulation for research and clinical applications.