bluuebunny/crossref_metadata_2025_split huggingface dataset:
Timing of dispersal in juvenile jewel fish during development is unaffected by available space
Authors: Chen Michael J. , Coss Richard G. , Godthwaite Ronald O. 
Published: January 2005

AbstractThe spatial distributions of 2 groups of sibling juvenile jewel fish were examined between 58 and 99 days of age to determine the effects of spatial experience on the timing of dispersal from a more aggregative behavioral mode. One group was provided a seminatural 1000‐liter aquarium, the other with 70% less space per fish, but both groups were able to observe the same number of fish. Using a computer and digitizing tablet, distances between 1st–6th nearest neighbors were measured from time‐sampled video recordings of spatial distributions in either overhead or underneath plan views. Both groups exhibited changes in aggregative behavior that were remarkably similar. Between 65 and 92 days of age, both groups showed gradual dispersal, which accelerated abruptly at 93–99 days of age. These results suggest that the timing of dispersal is regulated by developmental processes operating independently of spatial experience.
Changes in appetitive behavior in weanling‐age rats: Transitions from suckling to feeding behavior
Authors: Stoloff Michael L. , Blass Elliott M. 
Published: January 2005

AbstractTo help identify determinants of rat appetitive behavior during the weanling period, rat pups 17–32 day of age were studied in a Y‐maze. One arm of the maze provided pups with the opportunity to suckle a lactating or nonlactating anesthetized female. The other arm always contained a familiar food, either liquid diet or ground laboratory chow. In some experiments the dam was separated from the food compartment by a thin gauze screen. In other tests maternal contact could be maintained in the feeding goal but suckling in that compartment was prevented by nipple involution. Age was the major determinant of choice, with more older animals choosing the food arm. Availability of maternal contact in the feeding compartment increased the percentage of rats that chose to feed by about 20% at all ages studied. Food quality, but not quantity, affected choice at each age, as did lactational status. Prior food, water, and maternal deprivation (2 or 24 hr) did not affect choice behavior at any age but did influence behavior in the goal box. These findings are discussed within the context of the changing demands faced by the rats during the weaning period.
Developmental changes in head‐circumference and mental‐performance growth rates: A test of epstein's phrenoblysis hypothesis
Authors: McCall Robert B. , Meyers Edmund D. , Hartman John , Roche Alex F. 
Published: January 2005

AbstractEpstein's phrenoblysis states that brain growth and mental growth occur in correlated spurts at 3–10 months and 2–4, 6–8, 10–12 or 13, and 14–16 or 17 years of age. The present study was the first to test statistically such spurts in head‐circumference and mental‐age growth rates and to assess any correspondence in individual differences between spurts in the two variables in a single sample of children measured serially between 2.5 and 17 years of age. While the statistically significant spurts observed in each variable did fall within the hypothesized age periods, the chance rate for such theoretical concordance was high and several hypothesized spurts were not supported. Moreover, no relationship existed within individuals between head‐circumference and mental‐age growth‐rate patterns.
Dietary effects on rhesus social behavior: Altered amino acid diets
Authors: Chamove A. S. 
Published: January 2005

AbstractTwenty‐one monkeys continuously fed one of five diets high in tyrosine, histidine, alanine, glycine, or tryptophan between the ages of 1 and 12 months were compared with 20 controls. Social behavior either (a) while on the diet and tested in familiar groups of four or (b) while on a normal diet and paired with unfamiliar monkeys showed no effects of the high amino acid diets, confirming a previous analysis of learning ability.
Parabrachial nuclei damage in infant rats produces residual deficits in gustatory preferences/aversions and sodium appetite
Authors: Hill David L. , Almli C. Robert 
Published: January 2005

AbstractTen‐day‐old rats sustained bilateral electrolytic lesions of the parabrachial nuclei in the pons (PBN). Growth measures and tests of sensorimotor, feeding and drinking behaviors, sodium appetite, and gustatory capacities were made between age 1 and 150 days. PBN rats displayed a transient period of attentuated suckling, as evidenced by body weight loss. When tested soon after weaning, PBN rats were hyperdipsic in response to cellular dehydration and during food deprivation. This effect, however, was temporary. When tested as adults, PBN rats were hypodipsic in response to extracellular fluid volume depletion, they displayed alterations in sodium appetite, showed “exaggerated” preferences and aversions to saccharin and NaCl solutions, and they displayed attentuated quinine aversions. These results are generally similar to the behaviors of rats sustaining more central gustatory pathway lesions as adults. The functional significance of the PBN in the developing rat for preference/aversion and sodium appetite behaviors are discussed.
Sex and strain differences in the developmental activity profile of the rat tested over clean vs home cage bedding
Authors: Buelke‐Sam J. , Sullivan P. A. , Kimmel C. A. , Nelson C. J. 
Published: January 2005

AbstractIn the first of two experiments, CD rat litters were used to characterize activity patterns obtained in a size‐adjustable, single photodetector chamber. Beginning on postnatal Day 10 or 12, pups were tested repeatedly over clean bedding (C) or over bedding removed from each pup's home cage (HC). In C rats of both sexes and in HC females, short‐term activity levels peaked on Day 16. However, HC males displayed and earlier and even greater elevation in activity from Day 12 to 16. This overall pattern was found in rats tested either every second or every fourth day. In the second experiment, Long‐Evans pups were assigned to each testing condition (C vs HC) and activity measured beginning on Day 12. Peak levels were seen in all Long‐Evans rats on Day 16 and only females showed significant alterations as a function of bedding condition. When overall activity levels of the two strains were compared, significant differences were found on Days 12, 24, 30, and 120 in males, and 12, 24, and 30 in females. Significant differences between strains in activity as a function of bedding condition were found in males on Days 12, 20, 24, and 120 and in females on Days 12, 30, and 60. These data confirm the generality of a developmental hyperactivity phase in isolated juvenile rats. However, different patterns of hyperactivity were found in male vs female rats across strains. CD males were more active in the presence of HC olfactory cues, while in Long‐Evans rats, female activity was affected more by bedding condition.
The mother‐litter relationship in developmental rat studies: Cannibalism vs caring
Authors: DeSantis Darlene T. , Schmaltz Leonard W. 
Published: January 2005

AbstractThis incidence of cannibalism was studied in a series of developmental studies (on neonatal lesions, prenatal stress, prenatal surgery, unoperated controls) in which rats were manipulated during either the prenatal or early postnatal periods. Cannibalism during the preweaning period occurred in from 0 to 33% of the litters, dependig on the treatment group. It was found in most cases, however, that mothers who cannibalized were also good caretakers of their remaining pups. The same litters were also involved in preweaning tests of mother‐young interactions to determine if experimental treatments altered the maternal‐filial relationshi. It was found that as early as postnatal Day 4, nursing episodes were predominantly pup‐initiated in the lesioned litters but mother‐initiated in control litters.
Neonatal sex‐steroid hormones and muscular strength of boys and girls in the first three years
Authors: Jacklin Carol Nagy , Maccoby Eleanor E. , Doering Charles H. , King David R. 
Published: January 2005

AbstractFive sex‐steroid hormones were assayed in umbilical cord blood. Strength was assessd in children in three samples at several ages from birth to 33 months. At defferent ages, differents strength measures were tatken, viz., at birth, prone head responses; at 3 months, leg strength; from 6 to 33 months, grip strength. Boys had higher average strength scores than girls but the sex differences were small and did not increase or decrease over the age period studied. Across‐age strength scores showed a significant relation to androstenedione and a significant interaction of sexc and progesterone. Both boys and girls with higher strength scores had lower androstenedione. Girls with high cord blood progesterone showed low strength with boys with high progesterone showed high strength. There were no sex differences in androstenedione or progesterone level. The androstenedione finding did not replicate across samples but the Progesterone × sex interaction was replicated in all three sample. No relationship was found between strength and other hormones assayed: Tstosterone, estradiol, and estrone.
Conditioning of aversion to an odor paired with peripheral shock in the developing rat
Authors: Kucharski David , Spear Norman E. 
Published: January 2005

AbstractFour experiments examined an apparent inability to associate, or severe deficiency in associating, an odor and a footshock during the first 2 weeks of life in the rat, a cue‐to‐consequence relationship that had formerly seemed age‐dependent. With a particular classical conditioning procedure, however, significiant conditioning occurred on postnatal Days 6 and 10 with relatively few conditioning trials; the procedure employed an odor explicitly unpaired with footshock (CS−), as well as an odor paired with footshock (CS+) (Experiment I). Experiment II assessed the contribution of a CS− exposure in the conditioning of rats 8, 15, or 50 days of age. For 8‐day‐olds, exposure to both the CS+ and CS− resulted in conditioned aversion to the CS+ after eight but not one conditioning trials, but neither 1 nor eight trials with only a CS+ produced conditioning. For 15‐ and 50‐day‐olds, conditioning to the CS+ odor was significant after one trial with, but not without, a specific CS− with eight trials, however, conditioning was significant with or without the specific CS−. It was verified with the 50‐day‐olds in Experiment III that aversion to the CS+ was conditioned with a single trial only if a CS− had been presented, with a slight trend toward superior conditioning if the CS− preceded rather than followed the CS+ during conditioning. Experiment IV tested the hypothesis that exposure to the distinctive CS− odor sensitzes the animal to the specific properties of the CS+ odor. Fifteen and 50‐day‐old rats were given one conditioning trial with a CS+ odor that was either unaccompanied by a CS− or that was presented with a CS− odor in the same context as the CS+ or in a different context. For both 15− and 50‐day‐old rats, conditioning to the CS+ occurred only for animals given the CS− in the same context as the CS+, indicating that the hypothesis should be rejected. The results generally indicate rapid and substantial odor‐footshock conditioning in rats as young as 6 days of age, with CS‐exposure established as perhaps especially significant for conditioning early in life, but important for rats of all ages tested, from infancy to adulthood.
Influence of neonatal handling on blood pressure, locomotor activity, and preweanling heart rate in spontaneously hypertensive and Wistar Kyoto rats
Authors: Tucker Diane C. , Johnson Alan Kim 
Published: January 2005

AbstractThis experiment tested the hypothesis that increased stimulation early in development would (a) alter developmental changes in heart rate and behavioral reactivity and (b) affect the level at which blood pressure was regulated in adulthood. For this purpose, the effects of daily handling and maternal separation (3 min per day) on both behavioral and cardiovascular measures were examined in spontaneously hypertensive (SHR) and normotensive control Wistar Kyoto (WKY) rats. Prior to weaning, elevated heart rates in pups handled during the first postnatal week were most pronounced among 4‐week‐old prehypertensive SHR pups. Early handling affected behavior observed during openfield testing similarly in young adult rats of the SHR and WKY strains (e.g., increased locomotor activity on the first day of testing). In female rats of the WKY strain, early handling resulted in a lower baseline blood pressure; the blood pressure; the blood pressure of SHR rats was not affected by increased stimulation in infancy. Examination of longitudinal data yielded no support for a direct association between behavioral reactivity or preweaning heart rate and high blood pressure. These findings demonstrate the influence of both early environmental conditions and genetic factors on maturation within the cardiovascular system and suggest that genetic models of pathological conditions may provide a productive means of examining environmentally shaped aspects of individual differences in physiological regulation.
Home odor preferences in young hares (Lepus capensis syriacus): Effects of age and role of maternal presence
Authors: Stavy M. , Goldblatt A. , Terkel J. 
Published: January 2005

AbstractThe odor preferences of mother‐reared and hand‐reared young hares between 1–30 days of age were studied. Subjects were exposed daily to three choice tests in which the following pairs of odors were presented: home cage odor (HCO)‐neutral odor (NO); HCO‐strange cage odor (SCO); SCO‐NO. All young strongly preferred their HCO over SCO throughout the 30‐day period. HCO was preferred over NO until the age of 20 days, while avoidance of SCO was shown during the first 10 or 20 days. The same experiment conducted on postweaned hares (31–50 days of age) revealed a strong preference for SCO over both HCO and NO.These findings may be interpreted with respect to the natural history of the hare and its unusual mother‐young relationship, which, in the wild, is limited to a single daily meeting for nursing. It is suggested that the highly precocial hare recognizes and prefers its home odor independently of any maternal contribution to that odor, possibly relying on odor cues from its own body to return to its nursing site. Other possible advantages of these olfactory preferences, including predation avoidance and facilitation of social relationships, are discussed.
The organization and stability of sleep states in fullterm, preterm, and small‐for‐gestational‐age infants: A comparative study
Authors: Watt Jan E. , Strongman K. T. 
Published: January 2005

AbstractSleep state organization in the neonatal period was compared for groups of fullterm, preterm, and small‐for‐gestational‐age infants. Preterm and small‐for‐gestational‐age groups were found to have greater rates of state change than the fullterm group, and maternal perception of the infants was found to be negatively correlated to rates of state change in the preterm infants. Small‐for‐gestational‐age infants had more active sleep without rapid eye movements than fullterm or preterm infants. The findings are discussed with regard to implications for CNS organization and possible early identification of infants at risk of developmental problems.
Perinatal dietary supplementation with a commercial soy lecithin preparation: Effects on behavior and brain biochemistry in the developing rat
Authors: Bell J. M. , Slotkin T. A. 
Published: January 2005

AbstractRats exposed perinatally to dietary commercial soy lecithin preparation (SLP) showed alterations in sensorimotor development and brain cell maturation. Latencies for righting responses (measured on postnatal Days 1–4) and negative queotaxis (measured on postnatal Days 5–8) were shorter in the SLP treated animals. This pattern was accompanied by specific alterations in cerebellar development; biochemical markers for cellular maturation indicated a compression of the ontogenetic time course, as assessed by ornithine decarboxylase (ODC) activity, and levels of nucleic acids and proteins. In contrast, cellular development in the cerebral cortex indicated a generalized slowing of the time course of maturation and a deficit in the number of cells which persisted into adulthood. Behavioral abnormalities also did not disappear in adulthood, as morphine analgesia was markedly reduced in the SLP group. These results indicate that exposure of the fetus and neonate to dietary SLP during development leads to regionally specific alterations in brain cell maturation associated with disruption or behavioral patterns.
Maternal behavior in rats and the effects of neonatal progestins given to the pups
Authors: Birke Lynda I. A. , Sadler Dawn 
Published: January 2005

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 period.
Maturation of olfactory exploration in golden hamsters
Authors: Schoenfeld Thomas A. , Corwin James V. 
Published: January 2005

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 (Rowell, 1961).
An experimental study on developmental changes of maternal discrimination of infants in crab‐eating monkeys (Macaca fascicularis)
Authors: Negayama Koichi , Honjo Shigeo 
Published: January 2005

AbstractIndividually reared mother‐infant dyads of crab‐eating monkeys (Macaca fascicularis) were observed cross‐sectionally in their mother‐infant relationship. In infants aged from 0 to 5.0 months, rather drastic changes were found both at 0.5–1.0 and 2.0–3.0 months of age. For an explanation of these changes, developmental processes of discrimination between mother and infant were analyzed cross‐sectionally by exchanging mother‐infant combinations. The results indicated that the first 0.5 months postpartum was characterized as a behaviorally nondiscriminating stage where nipple discrimination by infants was the only exception. The latter half of the first month was the beginning of a nonaggressive discrimination stage by mothers, indicated by lipsmacking and sniffing and in infants by clinging. When infants reached the age of 2.0–3.0 months, the mothers' nonaggressive discimination with lipsmacking decreased, and her aggressive discrimination of alien infants increased. In addition to maternal visual discrimination of infants' physical appearances, differences in infants' odor and/or their method of nipple contact were suggested to affect the mothers' differential behaviors.
Postnatal locomotion development in a neurological mutant of rolling mouse nagoya
Authors: Tamaki Yoshitaka , Oda Sen‐Ichi , Kameyama Yoshiro , Kameyama Yoshiro 
Published: January 2005

AbstractPostural control skills and quadrupedal locomotor pattern in infant rolling mice, a neurological mutant, were observed in the following situations: hindlimb support when suspended, rope descent, narrow path traverse, quadrupedal locomotion on an inclined corridor, and swimming behavior when entirely submerged. Until the second week of age, rolling mice developed primitive responses similar to, or somewhat slower than, their unaffected littermates, but failed to show mature adaptive and coordinated movements from Days 16–18 onward in hinblimb support and rope descent tests. The gait was broadbased and they frequently lurched, rolled over on the side in the narrow‐path and incline situations. Also, swimming behavior was extremely clumsy with varying degrees of disturbed rhythm and inconsistent movement of hindlimb paddling. These findings might result from an immature development of hindlimb muscle tonus control system and distortion of smooth and orderly sequence of hindlimb muscular contractions which characterize skillful quadrupedal locomotion.
Development of auditory localization in dogs: Single source and precedence effect sounds
Authors: Ashmead Daniel H. , Clifton Rachel K. , Reese Ellen P. 
Published: January 2005

AbstractThe development of auditory localization in dogs was investigated in a litter of 12 pups. Behavioral auditory localization consisted of orienting responses to dog vocalizations presented from loudspeakers 90 degrees to each side. Sounds were presented in two configurations, single source (only one loudspeaker) and precedence effect (both loudspeakers, with one slightly leading the other). Localization began around 16 days after birth, for single‐source sounds. This is consistent with previous observations and with findings on dogs' auditory neural development. Single‐source sounds were localized earlier during development than precedence‐effect sounds. This ordering resembles findings on human infants and can be related to neuroanatomical investigations of mammalian brain structures mediating single source versus precedence effect localization.