bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aggressive behaviors in adult rats deprived of playfighting experience as juveniles
Authors: Potegal Michael , Einon Dorothy 
Published: January 2005

AbstractMatched litter mates were reared in one of three conditions: in pairs or in isolation with or without one hour of daily playfighting experience from 20 to 50 days of age. The rats were then regrouped within condition so that they lived with identically reared cagemates for a month. This regrouping eliminated the transient effects of isolation such as increased fearfulness. When tested as adults, there was no effect of early rearing condition on the probability of intraspecific aggression or muricide, although isolation‐reared rats were less likely to retrieve the mice. However, isolation rearing reduced the latency to initiate shock‐induced defensive aggression and increased both its frequency and intensity. Isolated animals which had been given daily playfighting during development did not show the effects of early social deprivation. The mechanisms through which playfighting experience shapes later defensive behavior remain to be determined.
Sensory processing in the term and preterm infant: Use of reflex modification procedures
Authors: Anday Endla K. , Cohen Michelle E. , Kelley Nancy E. , Hoffman Howard S. 
Published: January 2005

AbstractThe present study uses the glabellar reflex and reflex modification procedures to assess acoustic and tactile sensory processing capabilities in the human neonate. Fourteen term infants and 28 clinically stable preterm infants were given identical test paradigms. Augmentation testing consisted of a 16 V dc tap presented simultaneously with a 90 dB SPL tone; inhibition testing consisted of a 16 V tap preceded 900 msec. by an identical tap. All 14 term infants showed augmentation with 8 of 14 at p < 0.05 level and eleven of 14 showed significant inhibition at the 900 msec intertap interval. However, only 12 of 28 preterm infants demonstrated significant augmentation and none showed reliable inhibition. These data indicate that areas of the central nervous system that process sensory stimuli are not fully developed at the time of birth even in the term infant. Further, the neural system for augmentation and inhibition may be independent of each other.
Anterior and posterior, but not cheek, intraoral canulation procedures elevate serum corticosterone levels in neonatal rat pups
Authors: Spear Linda Patia , Specht Steven M. , Kirstein Cheryl L. , Kuhn Cynthia M. 
Published: January 2005

AbstractImplantation of intraoral cannulas is a procedure that has been typically assumed to be relatively unstressful in neonatal rat pups. To test this assumption, endocrine responses to such implantations were compared with those of other standard procedures. In Experiment 1, corticosterone and growth hormone (GH) levels were assessed in 4‐day‐old rat pups placed in an incubator for 15 or 60 min following either: no treatment, subcutaneous (sc) injection of 0.9% NaCl, anterior or posterior intraoral cannulation, ice anesthesia or ether anesthesia. Corticosterone levels were elevated relative to nontreated controls 15 min after all treatments except sc injection. These levels remained elevated after 60 min in both cannulation groups and the ice anesthesia group. In Experiment 2, the ability of ether anesthesia to reduce the hormonal response to the cannulation procedures was assessed in addition to examining the hormonal response to intraoral cannulations through the cheek in 4‐day‐old rat pups. Ether did not attenuate the corticosterone response to either anterior or posterior cannulations. Pups subjected to the cheek cannulation procedure did not exhibit any significant alterations in serum corticosterone levels when compared with nontreated control pups. GH levels were found to differentiate less among the various procedures than corticosterone levels, with GH levels generally being low in all groups, including nontreated control animals. These data suggest that cheek placement is less stressful than anterior and posterior placements and may provide a viable alternative in studies necessitating the implantation of a cannula into the buccal cavity during the early postnatal period.
Changes in sensitivity to the odor of androstenone during adolescence
Authors: Dorries Kathleen M. , Schmidt Hilary J. , Beauchamp Gary K. , Wysocki Charles J. 
Published: January 2005

AbstractWhile it has been reported that most, if not all, very young children are able to detect the odor of 5α‐androst‐16‐en‐3‐one (androstenone), approximately 40–50% of human adults cannot detect its odor. The present study focused on changes in sensitivity to androstenone was determined in 247 subjects aged 6 to 50. There was a significant increase in the number of males anosmic to androstenone between 9–14 and 15–20 years of age, and a significant increase in threshold with age among males able to detect the odor. We infer that a smaller percentage of females than males becomes anosmic to the odor of androstenone during development, and those able to detect it apparently show a decrease in threshold with age. No age‐related changes were observed in tests of pyridine or d, l, ‐β‐phenylethylmethylethyl‐carbinol (PEMEC).
Isolation distress and maternal comfort responses of two‐week‐old rat pups reared in social isolation
Authors: Hofer Myron A. , Shair Harry N. , Murowchick Elise 
Published: January 2005

AbstractIn 2‐week‐old rats, isolation from social companions in an unfamiliar place elicits ultrasonic vocalization rearing and locomotor behavior. These responses are prevented and close body contact is maintained if littermates or the dam are present. It has generally been believed that such isolation distress and comfort responses develop as a result of prior social experience. We reared pups in isolation from the third postnatal day and found essentially normal responses. A second experiment replicated and extended these results to pups reared in isolation from the day of birth. Isolation‐reared pups did have higher levels of ultrasonic vocalization than their normally reared littermates, lower body weight, and lower post‐test temperatures. We conclude that a lenghthy period of close body contact and frequent social interactions with conspecifics are not necessary for the development of attachment responses in this species.
Effects of undernutrition and handling during suckling on shuttle avoidance and footshock escape behavior and on plasma glucose levels of young rats
Authors: Rocha Joao B. T. , Vendite Deusa 
Published: January 2005

AbstractThe present report examined the effects of undernutrition and handling on shuttle and footshock escape avoidance behavior of female rats. Rats were undernourished by feeding their dams a 7% casein diet from birth until 23 days of life. During this period rats were separated from their dams for 4 to 10 min. On days 23 and 24 after delivery, young rats were subjected to sessions in a two‐way shuttle avoidance task. The results demonstrated that nonstimulated and stimulated undernourished and stimulated well‐nourished rats escape faster than nonstimulated well‐nourished animals from footshock during the first session of shuttle avoidance. Further, undernutrition interacted with early stimulation, disrupting the shuttle avoidance behavior of female rats. These results suggest that both undernutrition and early handling can change the footshock behavior of young rats. Undernourished rats presented lower basal glucose levels than well‐nourished animals, but responded to shuttle avoidance testing in the same way as do normal rats, increasing the glucose levels.
Maternal behavior variations and adaptations, and pup development within litters of various sizes in Wistar rat
Authors: Deviterne Dominique , Desor Didier , Krafft Bertrand 
Published: January 2005

AbstractVariations of two maternal behavior components (time spent with litter and rapidity of pup retrieving) as well as certain physical and developmental characteristics of pups (weight, relative weight gain, and neuromotor maturation) in rats were simultaneously studied in 29 various‐sized litters in which interindividual variations were not experimentally amplified. Results showed mothers' behavioral adaptations to littes' characteristics (size and weight). Time spent with young was linked to litter size, whereas rapidity of pup retrieving was related to the pups' physical characteristic. Beyond these adaptive variabilities, residual variations subsisted between mothers. These variations were determinant for differences in pup development for only one component: the time that mothers spent with their litters, while pup retrieving component variations did not have any effect.
Inhibition of infant glucocorticoid stress response: Specific role of maternal cues
Authors: Stanton Mark E. , Levine Seymour 
Published: January 2005

AbstractPrevious work from this laboratory has shown that passive contact with ananesthetized lactating dam eliminates the corticosteroid stress response to novelty in 12‐, 16‐, and 20‐day‐old rat pups. In the present study, we further examined some of the sensory and developmental aspects of this phenomenon. In two experiments, we asked whether inhibition of the corticosteroid stress response is related exclusively to contact with a maternal stimulus as opposed to other social stimuli. Experiment I compared the effectiveness of contact with an anesthetized dam vs. an anesthetized adult male rat. At 12 and 16 days of age, contact with an adult male was some what effective in reducing stress responsiveness, whereas at 20 days, contact with an adult male was entirely ineffective. At all ages, contact with an anesthetized dam was an effective inhibitor of the stress response. Experiment II compared the relative effectiveness of contact with an anesthetized dam vs. an anesthetized pup was entirely ineffective in inhibiting the glucocorticoid stress response. In Experiment III, the effect of maternal contact was assessed during a period of development when the biological, and presumably social, significance of the lactating‐dam stimulus is changing. In this study, 20‐, 24‐, and 28‐day‐old rat pups revealed a progressive decrement in the ability of maternal contact to inhibit stress responsiveness. These findings replicate and extend our previous ones by showing that maternal stimuli play a special role in the modulation of pituitary‐adrenal activity during development.
Control of intake by human‐milk‐fed infants: Relationships between feeding size and interval
Authors: Matheny R. J. , Birch L. L. , Picciano M. F. 
Published: January 2005

AbstractDiurnal feeding behavior of 24 exclusively breast‐fed infants was examined at 2, 4, 6, 8, and 12 weeks to assess whether milk intake at a feeding was related to previous (preprandial) or subsequent (postprandial) intervals between feedings. Amount of human milk consumed per feeding and intervals between feedings were measured over a 72‐hr period. Correlation analyses revealed that volume of milk ingested at a feeding (meal size) was positively related to preprandial interval at all 5 ages (r =0.39–0.47, p < 0.0001). Meal size was likewise related, but not as strongly, to postprandial interval at 4 of the 5 time points examined (r=0.17–0.25, p < 0.01). Results of the correlational analyses revealed clear, consistent preprandial correlations, providing evidence for a reactive type feeding pattern among the solely breast‐fed infants. Postprandial correlations, possibly reflect and anticipatory feeding pattern, were present but remained consistently low over the 3 months examined, providing little evidence of Aa developmental shift. This study provides a preliminary foundation for future fongitudinal studies that address the regulation of food intake among infants.
Proximity measures of social play in the laboratory rat
Authors: Hole Graham 
Published: January 2005

AbstractLitters of laboratory rats (Rattus norvegicus) were filmed between 21 to 60 days of age, and data on 700 social play bouts obtained. These were analyzed for information on how play bouts ended and on the spatial relationship between the players and their physical environment.The results suggest that social play in this species (a) does not appear to be a covert means of securing priority of access to resources such as food, females, or territory; and (b) does not appear to represent practice for behaving in the contexts within which “serious” adult aggression occurs (e.g., practicing being “territorial,” etc.).Players showed a strong preference for playing close to cover and away from exposed areas; if this is also true for wild rats, it would minimize the potential costs of play in terms of increased conspicuity to predators.
Time‐dependent effects of peer separation on lymphocyte proliferation responses in juvenile squirrel monkeys
Authors: Friedman Elliot M. , Coe Christopher L. , Ershler William B. 
Published: January 2005

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 are transient.
A descriptive analysis of the postnatal development of contact‐righting in rats (Rattus norvegicus)
Authors: Pellis Vivien C. , Pellis Sergio M. , Teitelbaum Philip 
Published: January 2005

AbstractThe development of contact‐righting by rats was studied from birth to weaning. Such righting involved both vestibular and tactile forms, which matured at different rates. At birth, only righting triggered by snout contact with the ground (i.e., trigeminal righting) had the adult form of cephalocaudal axial rotation in which the limbs flex to accommodate placement on the ground while the body is rotated to prone. Vestibularly triggerd righting from the supine position initially only activated head and neck rotation, and failed to recruit the shoulders and pelvis to rotate to prone. In the fully adult form, achieved by about 12 days, vestibularly triggerd righting activated shoulder‐led roration which passively carried the head and neck to prone, and then recruited the pelvis to rotate to prone. Asymmetrical contact of the body surface with the ground triggered both body‐on‐head (forequarter‐led) and body‐on‐body (hindquarter‐led) forms of righting. At birth, both involved limb righting movements (foreleg and hindleg, respectively), without rotation of the axial musculature: For both, the fully mature forms involved axial rotation by the shoulders and pelvis, respectively. In the adult, the body‐on‐body form of righting only occurs when the head is restrained by the experimenter; whereas in the infant it also occurs when the head is unrestrained, and thus simultaneously with those forms of righting which involve the forequarters. The simultaneous occurrence and differential rate of maturation of these forms of righting produce complex, seemingly bizarre, patterns of righting during development, which are unlike those present in adults. This study clearly shows that the postnatal development of contactrighting involves a complex interaction of righting subsystems.
Sex steroids at birth: Genetic and environmental variation and covariation
Authors: Sakai Laura M. , Baker Laura A. , Jacklin Carol Nagy , Shulman Ira 
Published: January 2005

AbstractThree sex‐steroids (estradiol, progesterone, & testosterone) were assayed from the umbilical cord blood of 58 same‐sex twin pairs in an investigation of the effects of sex, as well as genetic and environmental factors, on neonatal hormone levels. Although significant mean differences were found between boys and girls for both testosterone and progesterone, sex appeared to account for very little of the total variation for any of the hormones. Results showed that genetic influences significantly affected within‐sex variation in both estradiol and progesterone levels, while variations in the intrauterine (shared twin) environment accounted primarily for differences in levels of testosterone. Moderate correlations were also found among the three hormones. Multivariate biometrical analyses revealed these relationships to be explained by an underlying general factor of nonshared environmental influences affecting all three hormones. Genetic factors appeared to be specific to each hormone rather than correlated across hormones. These results suggest not only that genes are operating at this early age, but also that maternal and other prenatal factors (e.g., placental effects, uterine position) have a significant role in variations of sex‐steroids and possibly on later behaviors.
Neonatal 6‐OHDA lesions and rearing in complex environments: Regional effects on adult brain 14C‐2‐deoxyglucose uptake revealed by exposure to novel stimulation
Authors: Nobrega José N. , Saari Matti J. , Armstrong John N. , Reed Trudy 
Published: January 2005

AbstractBehavioral and neuromorphological data have suggested at least a partial interaction between the effects of norepinephrine‐depleting neonatal 6‐OHDA lesions and the effects of rearing in enriched environments. The present study examined the impact of both of these early manipulations upon regional brain uptake of 14C‐2‐deoxyglucose (14C‐2DG) in adulthood. Newborn rats received 6‐OHDA (50 mg/kg s.c.) or vehicle and, after weaning at 25 days, were reared in isolated versus enriched conditions. Regional brain 14C‐2DG uptake was then examined at 70–80 days of age—either in the home cage or while animals were being exposed to novel, presumably arousing, stimulation. Ninety‐seven brain regions were examined in eight separate groups. Results indicated that (1) Under baseline conditions, neither neonatal 6‐OHDA nor differential rearing conditions produced widespread alterations in regional brain 14C‐2DG uptake profiles. An overall enrichment effect was on only five brain areas, with rats reared in enriched environments showing lower levels of 14C‐2DG uptake (−20% to −30%) than isolated rats. Neonatai 6‐OHDA produced no main effect on 14C‐2DG uptake in any brain region. (2) In contrast, when 14C‐2DG uptake was assessed during exposure to a novel environment, five brain areas showed differential 14C‐2DG uptake in 6‐OHDA‐treated rats, and 20 brain areas showed differential uptake in rats reared in enriched conditions. (3) No significant interaction effect on brain regional 14C‐2DG uptake was observed between neonatal 6‐OHDA and environmental complexity factors. These results are consistent with the notion that enduring effects of rearing and early 6‐OHDA treatment may, independently, relate to a general reactivity factor. They also indicate that some effects of early neurochemical injury and subsequent experiential factors may not be apparent under normal resting conditions, but only become evident in the presence of appropriate “activating” stimulation. © 1992 Wiley & sons. Inc.
Mobile surrogate mothers and the development of exploratory behavior and radius of action in infant long‐tailed macaques (Macaca fascicularis)
Authors: Duijghuisen John A. H. , Timmermans Paul J. A. , Vochteloo Johan D. , Vossen Jo M. H. 
Published: January 2005

AbstractOne of the effects of rearing young monkeys on surrogate mothers is a delay in the development of exploratory behavior. An important question is which difference between mother and surrogate mother caused this delay. We hypothesized that the mothers' carrying the infant through the environment promotes the development of exploratory behavior and the radius of action of infant macaques. Using surrogate mothers, we reared 9 infants in a peer group with immobile surrogates and 10 infants in another peer group with mobile surrogates.During the 3rd to the 6th month, we observed each infant for 30 min weekly, collecting observational data on several behavioral parameters and on time spent in several areas in the cage. Results showed that exploratory behavior and an increase in radius of action developed more rapidly in the mobile‐reared infants. © 1992 Wiley & sons. Inc.
Oral capture and grasping of an artificial nipple by rat fetuses
Authors: Robinson Scott R. , Hoeltzel Thomas C. M. , Cooke Kristin M. , Umphress Sarah M. , Smotherman William P. , Murrish David E. 
Published: January 2005

AbstractAlthough born blind and deaf, newborn rats exhibit a remarkable capacity to recognize and gain access to the nipples of the lactating mother. However, it is well‐known that full‐term rat neonates will not attach to an artificial nipple. In the present study, an artificial nipple fashioned from soft vinyl was presented to rat fetuses from E17‐E21 of gestation. Fetuses showed side‐to‐side head movements that resulted in oral capture of the nipple on E18 and exhibited a direct nipple‐grasping response from E19 through term. Frame‐by‐frame analysis of videotape records of E21 rat fetuses revealed that tactile contact with the artificial nipple elicited mouthing, licking directed at the nipple, forelimb treadling, and grasping of the nipple. Fetuses also exhibited components of aversive behavior, including facial wiping and head turning, that appeared to terninate oral contact with the nipple. Morphine pretreatment reduced the expression of aversive responses and promoted licking and grasping of the artificial nipple. In addition to documenting the prenatal ontogeny of this important neonatal behavior, these findings imply a role for endogenous opioids in the newborn rat's first suckling episode. © 1992 Wiley & sons. Inc.
Reactivation of nonassociative memory
Authors: Richardson Rick , Wang Peiyin , Campbell Byron A. 
Published: January 2005

AbstractThe orienting response to an auditory stimulus, as measured by a decrease in heart rate, habituates rapidly, and at the same rate in preweanling and adult rats. Although adult rats retain this nonassociative memory for at least 7 days, prewealing rats show extremely rapid forgetting. In the preweanling, forgetting of this nonassociative memory appears to be complete after just 24 hr (Richardson & Campbell, 1991b). The results of several experiments in the present study with preweanling rats demonstrated that this type of nonassociative memory could be reactivated by presenting a fractional component of the original eliciting stimulus just prior to testing. The effectiveness of the reactivation treatment was critically dependent upon both the number of reactivating stimuli presented and the duration of those stimuli. Reactivation was also found to be stimulus‐specific in that presentation of an auditory stimulus qualitatively different from that used in training (white noise instead of a pure tone) did not reactivate the memory. Control groups in each experiment demonstrated that the reactivation treatment facilitated retrieval of the prior nonassociative memory and did not produce new learning. A possible process through which nonassociative memories can be reactivated is discussed. © 1993 Johan Wiley & Sons, Inc.