bluuebunny/crossref_metadata_2025 huggingface dataset:
Reaction time and the psychological refractory period in children and adults
Authors: Surwillo Walter W. , Titus Thomas G.
Published: January 2005

The psychological refractory period–the prolonged reaction time RT to the second of 2 closely‐spaced stimuli–was investigated in groups of 13 children and 13 adults. Subjects responded as fast as possible to the 2nd of 2 loud clicks that were presented after a soft click which served as a ready signal. The inter‐stimulus interval ISI, or time between loud clicks, was investigated as an independent variable. The results for ISIS of 50, 100, 250, and 500 msec confirmed the existence of an inverse relationship between RT and ISI. In accordance with the hypothesis investigated, RT was more prolonged in children than in adults as ISI decreased. Findings were consistent with the view that refractory period RP of aninformation‐processing element in the central processor is longer in children than in adults. A single‐channel model of information processing was proposed which could explain the inverse relationship between RT and ISI; could account for the slope differences between the RT vs ISI curves from children and adults; and could account, in part, for the overall longer RTs of children than of adults.
Actions of atmospheric ionization on spontaneous activity of an amphibian larva
Authors: Olivereau Jean‐Michel , Aimar Christian
Published: January 2005

In Pleurodeles waltlii (Urodela) larvae, spontaneous activity and the tendency to leave water are significantly influenced by artificial air ionization. Atmospheric ions of negative and positive polarities have opposite effects: the latter reduce spontaneous activity by 48% whereas negative ions increase it by 39%. This difference must be considered the result of a specific behavioral effect rather than attributable to the stage of development of the larvae. A comparison of our results with data in the literature indicates that the action of the air ions on amphibian activity may involve the modulation of serotonin and prolactin releases.
Ontogeny of behavior in two inbred lines of selected mice
Authors: Van Abeelen J. H. F. , Schoones A. H.
Published: January 2005

The development over 11 ages of 14 reflex responses, 26 behavioral components, jumpiness, and left‐right discrimination learning was studied in 2 strains of mice genetically selected for high (SRH) and low (SRL) rearing response frequency. Significant age‐dependent differences between the strains were found mainly, but not exclusively, in the behavioral components, e.g., rearing, jumping, scratching, defecating. Two‐week‐old pups of both strains showed good acquisition and retention in learning tests without shock, but the „jumpy”︁ behavior disturbed performance to a certain degree in the SRH strain. Although less active initially, SRH mice were ahead at later developmental stages. Whether these differences are determined by the gene controlling rearing frequency or by other genes remains undecided.
Effects of thyroxine on infant development of undernourished rats
Authors: Jen Catherine Kai‐Lin , Wehmer Francine
Published: January 2005

The rehabilitative effects of exogenous thyroxine on infant development of undernourished animals were examined. Thyroxine injection accelerated the rate of body growth, age at eye opening, tooth eruption, and several emitted behaviors in undernourished infant animals. The data indirectly support previous findings that undernutrition induces hypothyroidism and that exogenous thyroxine might be an effective rehabilitative agent.
Mirror‐image response during the first two years of life
Authors: Schulman Allan H. , Kaplowitz Cheryl
Published: January 2005

Children aged 1–24 months viewed themselves in planar or distorted mirrors that were either clear or partially occluded. Analysis of videotaped records revealed that interest in viewing one's face did not vary with age among the 1‐ to 24‐month‐old subjects. All performed the simple behaviors of observing themselves although the older ones performed more complex (related) behaviors. Neither the flat nor the distorted mirror exposure was preferred suggesting that the infant observes the general configuration of the face for its intrinsic interest. Specific developmental trends were noted in the kind and amount of activity during the 1st 2 years of life culminating in a sequence of behaviors that suggested self‐recognition.
Paternal effects on the development of social behavior in Mus musculus
Authors: Smith Meredith L. , Simmel Edward C.
Published: January 2005

In order to extend the determination and description of effects of the father's phenotype on the development of social behavior in male mice, we tested 24 males from each of 2 highly inbred strains of Mus musculus, A/J and C57BL/6J. Approximately 1 week before the birth of the subjects, we replaced natural fathers with a foster parent such that, within each strain, 8 subjects had preweaning experience with same‐strain males, 8 with other‐strain males, and 8 with same‐strain females, in addition to their natural mothers. Observations of social behavior were conducted at 21, 50, and 60 days of age. The results showed effects of the foster parent's phenotype on the development of social exploration in both strains and, possibly, on agonistic behavior in C57BL/6J mice. The different effects in the 2 strains indicate mechanisms dependent on genotype.
Is hippocampal function in the adult rat impaired by early protein or protein‐calorei deficiencies?
Authors: Hall Robert D.
Published: January 2005

Much of the development of the rat's hippocampal formation occurs postnatally which suggests that this structure, like the cerebellum, may be especially vulnerable to early postnatal malnutrition. Radial‐maze performance and spontaneous alternation, two kinds of behavior requiring the integrity of the hippocampus, were assessed to determine whether hippocample function in the adult rat is mipaied as a result of protein restriction in either the prewaning, the postweaning or both stages of development. In three experiments the perormance of protein‐malnoruished rats in 8‐ and 12‐arm mazes did not differ significantly from that of well‐nourished rats. In a fourth experiment levels of spontaneous alternation in protein‐malnourished rats were like those of normal well‐nourished animals. Thus, The present experiments provide no evidence that hippocampal function is impaired as a consequence of early experiments provide no evidence that hippocampal function is impaired as a consequence of early protein deprivation. For the most part, a critical review of earlier studies of undernourished rats supports a similar conclusion.
Perceptual imprinting: Genetic influences and genotype‐environment interactions
Authors: Kovach Joseph K. , Wilson Gregory
Published: January 2005

One‐day‐old visually naive and experienced quail chicks (C. coturnix japonica) were mass‐screened for approach preferences by pairs of stimuli that were identical in size and luminance but different in color, or patter, or both color and pattern Subjects were drawn from the 18th generation of quail lines that were bidirectionally selected for color preferences, and from and unselected genetic control line. Experience consisted of 12 hr of unreinforced perceptual exposure to colored or white stimuli, with and without associated pattern. Data indicated strong genetic influences in the preferences of colors, which were partially generalized unselected preferences between colors and patterns. Joint exposure to color and pattern resulted in selective learning of color but not pattern. Systematic variations in postexposure choices between composite stimuli of colors and patterns were traced to variations of genotype, experience, and genotype‐experience interactions.
Individual recognition of human infants on the basis of cries alone
Authors: Green James A. , Gustafson Gwene E.
Published: January 2005

Human parents were asked to identify their infants on the basis of tape‐recorded cries that they had not previously heard. The cries of twenty 30‐day‐old infants were recorded just prior to a feeding, then rerecorded onto a test tape containing cries from three other infants. Eighty percent of mothers were able to recognize their infants's cries, as were 45% of fathers. An additional 140 adults (non‐‐parents) were tested in order to determine if the process of dubbing cries into test tapes had left extraneous auditory cues to infants' identities and if the foil infants were equally discriminable. The results indicated that parents' recognition was not based on extraneous cues and that, overall, the foils were appropriate distractors in the parents' task. Thus, the majority of parents can recognize their 30‐day‐old infants on the sole basis of acoustic cues contained in the infants' cries. The acoustic features that underlie this recognition are now being investigated.
Maturation of autonomic control in preterm infants
Authors: Fox Nathan A.
Published: January 2005

In order to investigate the development of autonomic control and its relation to postnatal illness, healthy term, healthy preterm, and preterm infants who had recovered from respiratory distress syndrome (RDS) were seen around the expected date of their birth, 40 weeks conceptional age (C.A.), and again at 3 months conceptional age. Three minutes of resting EKG were collected at each age point while the infant was in a quiet, alert state. Measures of resting heart period and heart period variability were derived. Results revealed the influence of maturity and illness on autonomic activity. RDS and healthy preterm infants, at 40 weeks C.A. exhibited a pattern of small heart period compared to healthy term. RDS preterm infants at 40 weeks C.A. exhibited less overall variability than either healthy group and across age displayed less short‐term variability than the healthy infants. The data suggest that autonomic activity during the early months of life may be affected by both pre‐maturity and postnatal illness. The significance of these data in understanding term/preterm differences in the neonatal period is discussed.
Early brain insult and cognition: A comparison of malnutrition and hypothyroidism
Authors: Strupp Barbara J. , Levitsky David A.
Published: January 2005

The effects of two biological insults, hypothyroidism and malnutrition, incurred during pre‐ and postnatal development were compared using a newly developed test of observational learning in rats. Whereas, early hypothyroidism produced a significant impairment in observational learning in recovered rats, no indication of any impairment was observed in rats recovered from early malnutrition. These results are important in that they demonstrate that tests of advantageous learning such as observational learning are sensitive to the kinds of early biological insult that lead to permanent cognitive impairment in humans. Moreover, these data further support the concept that the cognitive impairment observed during periods of malnutrition in humans and animals is not permanent.
Role of the caudate nucleus in recovery from neonatal mediofrontal cortex lesions in the rat
Authors: Vicedomini John P. , Isaac Walter L. , Nonneman Arthur J.
Published: January 2005

Ablation of medial prefrontal cortex impairs spatial discrimination learning in adult but not in neonatally lesioned rats. Orbital prefrontal cortex and adjacent convexity neocortex need not be left intact to observe this sparing of function. This study examined the possibility that the caudate nucleus, remaining intact after early medial prefrontal cortex lesions, might be involved in the observed behavioral sparing. Neonatal rats given combined lesions of the medial prefrontal cortex and head of the caudate nucleus were compared to age/litter‐matched sham‐operated controls on spatial alternation and place response acquisition and “reversal” tests. The results show that the performance of these neonatally lesioned subjects was deficient on both tests. The discussion centers on possible recovery mechanisms in rats given prefrontothalamic system damage early in life.
Maternal discrimination of pup sex in rats
Authors: Richmond Gail , Sachs Benjamin D.
Published: January 2005

In recent studies (Moore, 1981, 1982; Moore & morelli, 1979) it has been found that maternal female rats spend more time licking the anogenital region of male than female offspring. This discrimination of pup sex has important implications for the development of a number of sex differences in behavior later in life, and the present study was designed to re‐examine Moore' observations while allowing each pup to be individually identified. Litters of Sprague‐Dawley rats were delivered by Caesarean section, and the footpads of each animal were tattooed with India ink to permit identification throughout testing. Each litter was then fostered to a maternal female and remained with her except when observations of maternal licking were made–on the fourth, seventh, and tenth days after delivery. On each of these days, the foster mother was placed in a test chamber for 30 min, and each pup was then presented individually for a 10‐min session. During this time the number and duration of anogenital licking episodes were recorded. We found, as did Moore, that adult females do distinguish between their male and female pups, spending significantly more time licking the anogenital region of the males in their litters on all but the first day of testing. The posssibility that the attentional bias toward male young has important consequences for behavior later in life and contributes to behavioral differences between the sexes (Beach, 1979; Moore, 1982) makes the identification of individual animals throughout development important in the analysis of these effects.
Effects of social experience on the corticosterone response of adult rats to pup cues
Authors: Vogt Jerry L. , Hennessy Michael B. , Levine Seymour
Published: January 2005

Rat mothers whose pups have been removed show greater plasma corticosterone elevations when the pups are shocked and returned in a wire‐mesh basket that when only the wire basket is returned. For mothers housed with an adult male or virgin female, this differential adrenocorticoid responsiveness between the shocked‐pup and empty‐basket conditions was not observed unless the adult partner was removed 18 hr before testing. Nonlactating adults housed with pups and mother for up to 2 weeks exhibited corticoid elevations equivalent to the shocked‐pup and empty‐basket conditions whether tested with the mother or 18 hr after her removal. These results indicate that the differential pituitary‐adrenal responsiveness that female rats show to pup cues during lactation cannot be accounted for by the length of the mother's exposure to pups, and, further, that this relative responsiveness during lactation appears to be largely due to the suppression of adrenocorticoid reactivity to a nonsocial environmental disturbance.
Mother‐infant visual interaction in Japanese macaques
Authors: Ehardt C. L. , Blount B. G.
Published: January 2005

Pattern of visual interaction in mother‐infant dyadic behavior have been reported for human and nonhuman primates, including age and gender differences among rhesus macaques. Such findings are tested with data from two developmental periods (Weeks 1–8 and 21–36) on Japanese macaque mother‐infant visual behavior. Rates for look, infanct facial‐fixation, and eye contact are greater during the first period than in the second. In Weeks 1–8, infants interact visually with their mother significantly more than with any other kinship class. This pattern continues in the second period, with the exception of eye contact for female infants, and with relatively more attention to nonmatrilineal animals. In Weeks 1–8, all instances of eye contact between mothers and their female, but not male, infants are initiated by the mother. In Weeks 21–36, male, but not female, infants direct significantly more looks to their mother than they receive from her.
Short‐term exposure to an odor increases its subsequent preference in preweanling rats: A descriptive profile of the phenomenon
Authors: Caza Patricia A. , Spear Norman E.
Published: January 2005

Five experiments assessed the change in preference for an ambient odor after a brief period of exposure to that odor. Three minutes of exposure to a novel odor consistently increased subsequent preference for that odor. This effect occurred in preweanling rats 10 and 15 days of age even though, relative to the nest, the conditions of exposure were probably aversive tactually and thermally. There was relatively little variation in this effect between the ages of 10 Days postnatal and adulthood and over exposure durations ranging between 3 and 81 min. Substantial retention of this exposure effect was found for the 10‐day‐old rat, with no decline in induced preference over a 24‐hr period. The effect was unchanged by brief familiarization with the testing situation, but was eliminated by prior aversive experience with the testing situation. These results have implications for the design and interpretation of experiments that test learning and memory of odors, and emphazise generally the facility of the developing rat for processing olfactory information.
Acceleration of puberty in female mice by a urinary chemosignal from pregnant or lactating females: Timing and duration of stimulation
Authors: Drickamer Lee C.
Published: January 2005

Six experiments were designed to test the acceleration of puberty in young female mice treated with urine from pregnant or lactating females. Manipulations involved varying the age of onset for and duration of treatment with urine. For both urine sources the findings were similar: 1 day of treatment was insufficient to accelerate puberty, but a minimum of about 3 consecutive days of urine exposure begun before the mice were 30 days of age did hasten the onset of first vaginal estrus.
Radial arm maze performance in rats following neonatal dopamine depletion
Authors: Pearson David E. , Raskin Lisa A. , Shywitz Bennett A. , Anderson George M. , Cohen Donald J.
Published: January 2005

Neonatal dopamine (DA) depletion produces learning impairments both during development and throughout adulthood in the rat. The present experiment further investigated the memory capabilities of the dopamine‐depleted rat by assessing performance in the radial arm maze. Results showed that, following neonatal injection of 6‐hydroxydopamine and desmethylimipramine, lesioned rats perperformed more accurately than controls. In this paradigm, DA‐depleted rats tended to enter each arm to obtain a food pellet and not enter unbaited, incorrect arms. The difference in performance of control and treated rats could not be accounted for by differences in locomotor activity, body weights, or motivational factors. A computer analysis of the data revealed that DA‐depleted animals adopted a strategy of choosing adjacent arms consecutively, which probably accounted for their superior performance. Results are discussed in terms using algorithms versus extra‐maze cues to complete the maze following early brain injury.
Development of visually controlled maternal preferences in peking ducklings
Authors: Johnston Timothy D. , Gottlieb Gilbert
Published: January 2005

The interaction between natural visual and auditory stimulation in the control of filial behavior was studied in domestic mallard (Peking) ducklings during the first 3 days of postnatal life. Visual imprinting at 24 hr resulted in a visual preference for the familiar model over an unfamiliar model in each of two choice tests, one at 48 hr and one at 72 hr, but only if both models were silent. If both models emitted a recording of the mallard maternal call, the visual preference was found only in the later (72‐hr) test. Visuomotor experience between training and testing was found to be essential for the development of the visual preference at 72 hr, but the required experience was of a very general nature. Either a choice test with silent models or a period of social rearing (between 24 and 72 hr) provided effective experience. Thus, the ability to show a visual preference in the presence of the maternal call at 72 hr depends on experience, but not necessarily on further exposure to the imprinting object or to any specific aspects of the test situation. These results demonstrate the importance of normal visual, motor and/or social experience to the development of the visual control of filial behavior in ducklings.
Effects of a commercial soy lecithin preparation on development of sensorimotor behavior and brain biochemistry in the rat
Authors: Bell Joanne M. , Lundberg Paula K.
Published: January 2005

Pregnant rat dams and offspring were exposed to a 5 or 2% soy lecithin preparation or a control diet. Enrichment was either lifelong beginning at gestation, limited to the time preceding, or the time following weaning, or absent (constituting a “pure” control group). The most marked early sensorimotor deficits (reflex righting and swimming development) were seen in the 5% soy lecithin preparation group, although all soy lecithin preparation‐exposed offspring had elevated brain/body weight ratios and choline acetyltransferase levels. Later, animals exposed to lifelong 5 or 2% soy lecithin preparations were hypoactive, had poor postural reflexes, and showed attenuated morphine analgesia. The results indicate that dietary soy lecithin preparation enrichment during development leads to behavioral and neurochemical abnormalities in the exposed offspring.
Measures of growth, development, and sexual maturation in mongolian gerbils (Meriones unguiculatus): Effects of photic period during ontogeny
Authors: Clark Mertice M. , Galef Bennett G.
Published: January 2005

We examined, in Mongolian gerbils, the adequacy of two commonly used indices of rate of development, age at eye‐opening and age at vaginal introitus, as predictors of biologically important events: initiation of feeding on solid food and age at first parturition. We then enquired as to the interrelationships among body weight, eye‐opening, and vaginal introitus in Mongolian gerbils whose rates of development were manipulated by altering the extent of their exposure to illumination during ontogeny. We found that (1) age at vaginal introitus was significantly, but weakly, correlated with age at first parturition (Experiment I); (2) age at eye‐opening strongly predicted age of initiation of gnawing on solid food (Experiment II); (3) eye‐opening occurred at markedly different ages, but at the same body weight in gerbils reared under 0/24‐, 6/18‐, 12/12‐, and 24/0‐hr day–night cycles (Experiment III); and (4) vaginal introitus occurred at both different ages and different body weights in females reared under different day–night cycles (Experiment III).
The role of feeding regimens in the growth of neonate broad‐banded water snakes, Nerodia fasciata confluens, and possible effects on reproduction
Authors: Schudder Roy M. , Burghardt Gordon M.
Published: January 2005

The effect of different feeding regimens on the growth pattern of Nerodia fasciata confluens was tested using a litter of 18 captive‐born neonates. The snakes were divided among three feeding group: one group fed once per week, another fed twice per week, and the third fed on alternate days. The once per week and the twice per week groups were offered the same weight of food each week, while the alternate‐day group was offered food in excess of ingestion levels during each feeding session. The results indicate that there is a shift in the allocation of energy for growth in weight, snout‐vent length, and tail length with a change in the feeding regimen. Females were affected more than the males. The results are discussed in relation to their possible effect on reproduction.
Cue significance and response regulation in 3‐ to 6‐year‐old children's learning of multiple choice discrimination tasks
Authors: Bell J. A. , Livesey P. J.
Published: January 2005

The learning of multiple choice discrimination tasks of 3‐, 4‐, 5‐, and 6‐year‐old children was compared using the components of learning of cue significance and response regulation. No significant differences between age groups were found in the occurrence of cue significance learning, although the younger children's cue significance responses were less accurately related to task solution. On the two easier tasks, the component of response regulation improved significantly over the age range of 3–5 years. On the two more difficult tasks 6‐year‐olds' response regulation was significantly better than that of 4‐ and 5‐year‐olds. In a second experiment involving two different training procedures, 5‐yearqolds performed better than 4‐yearqolds. Only for 5‐year‐olds was performance with the procedure emphasizing response regulation superior to performance with the procedure emphasizing cue significance. These results are discussed in terms of an association between development of response regulation and maturation of hippocampal‐prefrontal cortex systems.
Effects of social experience on visually imprinted maternal preferences in peking ducklings
Authors: Johnston Timothy D. , Gottlieb Gilbert
Published: January 2005

If Peking ducklings are given social experience with agemates after their initial exposure to a maternal imprinting model (a stuffed mallard hen) their subsequent maternal preferences in simultaneous choice tests are different from those of isolate‐reared ducklings. Early in development (at 48 hr after hatching), they show a visual preference for the mallard over a redhead model, a difficult discrimination that isolated birds do not make (Experiment I). However, later in development (at 72 hr after hatching) the social experience interferes with the birds' maternal preferences, in that socially reared birds do not show a visual preference for the mallard over a pintail model, a preference that isolated birds do show at that age (Experiment II). It was found that it is the later social experience with agemates (between 48 and 72 hr) that actively interferes with the preference for the mallard model, because birds that have had only early social experience with agemates (between 24 and 48 hr) prefer the familiar mallard to the pintail model at both 48 and 72 hr (Experiment III). The conventional view of visual imprinting is that it serves to establish a maternal bond that does not require further experience with the mother to be maintained. Our results suggest that in the natural situation, where potentially interfering social stimulation is provided by siblings, continual exposure to the mother may be necessary to maintain the maternal bond even after it has been established.
Individual differences in mood in early childhood: Their relation to gender and neonatal sex steroids
Authors: Marcus Janet , Maccoby Eleanor E. , Jacklin Carol Nagy , Doering Charles H.
Published: January 2005

Predominant mood states were assessed for 104 children via 24‐hr mother diaries during the first 2 years of life. Consistent sex differences were found across ages and across cohorts: boys were more often reported to be in a happy/excited mood, girls in a quiet/calm mood. The sexes did not differ in the frequency of negative moods (including crying), however. Scores for happy/excited and quiet/calm mood states were quite stable across the ages sampled: 6, 9, 12, 18, and 26 months. These stabilities were generally greater for boys. Negative moods showed only borderline stability. Relationships between the mood scores and five sex‐steroid hormones (progesterone, androstenedione, testosterone, estrone, and estradiol), assayed from umbilical cord blood at the time of the children's birth, were assessed. For boys small, but significant, positive relationships were found between happy/excited moods and androstenedione, estrone, and progesterone. Correlations of opposite sign were found between these hormones and boys' scores for quiet/calm mood. For girls, the correlations were low and insignificant, but generally of opposite sign from those found for boys, and a number of hormones showed significant sex‐b‐hormone interactions in their relation to children's mood scores. The implication of these findings for the understanding of sex differences is discussed. Also discussed are the problems of interpretation posed by the intercorrelations among hormones when hormone scores are used for prediction of aspects of later development.
Early weaning does not accelerate the expression of nursing‐related taste aversions
Authors: Melcer Ted , Alberts Jeffrey R. , Gubernick David J.
Published: January 2005

Preweanling rat pups do not display an aversion to a flavor conditioned stimulus (CS) paired with illness if the CS is presented during the act of suckling. In contrast, 20‐day‐old pups do form such a conditioned taste aversion while suckling (Martin & Alberts, 1979). The dissolution of the nursing‐related “blockade” of toxiphobia correlates with the onset of solid food intake. Moreover, prevention of weaning prolongs the blockade; ingestive experience with solid food is necessary for the expression of nursing‐related taste aversions in 26‐day‐old “food naive” pups (Gubernick amp;Alberts, 1984). The present experiments tested the possibility that premature weaning to solid food might accelerate the onset of nursing‐related toxiphobia. Pups were weaned at 13 days of age and ingested only food and water. These prematurely weaned pups received taste aversion conditioning while suckling on Day 16, but showed no aversion to the CS flavor during a later food test. Thus, conditions that lead to early weaning (ingestion of solid food) do not accelerate the onset of taste aversions to mother's milk.
Adrenocortical and behavioral responses to limb restraint in human neonates
Authors: Malone Stephen M. , Gunnar Megan R. , Fisch Robert O.
Published: January 2005

Two experiments were conducted on human neonates examining their behavior and adrenocortical activity in response to physical restraint. In both experiments, newborns (9 per condition in Experiment I; 10 per condition in Experiment II) were tested in one of three conditions: Restraint, which involved strapping newborns to a circumstraint board for 20 min; Strapping Control, which involved strapping newborns to the board and then immediately taking them off the board and returning them to their cribs; and Control, which did not involve any restraining manipulation. In Experiment I, blood samples for plasma cortisol determination were obtained via heel‐stick immediately prior to the assigned manipulations and 30 min later. In Experiment II, only the postmanipulation blood sample was taken. Two behavioral states, Active Awake and Crying, were examined as indices of behavioral distress. In Experiment I, the effects of the blood sampling procedure on behavioral distress and plasma cortisol were significant; however, no significant effects of restraint were observed. In Experiment II, restraint was associated with small but significant increases in behavioral distress and in plasma cortisol levels.
Do newborn rabbits learn the odor stimuli releasing nipple‐search behavior?
Authors: Hudson Robyn
Published: January 2005

Rabbit pups do not need to learn postnatally the pheromonal cues releasing nipple‐search behavior. Pups delivered by caesarian section were able to attach to nipples as quickly as normally delivered controls in their first encounter with a lactating doe (Experiment I), and pups hand raised to Day 5 without postnatal experience of the nipple‐search pheromone even showed an improvement in their reactivity to it similar to normally raised controls (Experiment II). However, 1‐day‐old pups could be conditioned during the first nursing episode to respond with nipple‐search behavior to artificial odors painted on the mother's ventrum (Experiment III). Finally, pups conditioned on Day 1 but subsequently raised by hand or normally nursed showed retention of the conditioned responsiveness when tested on Day 5 (Experiment IV). These experiments suggest that although rabbit pups are capable of rapidly associating odors with suckling, they do not appear to depend on this ability under normal nursing conditions.
Environmentally induced analgesia: Ontogeny of a nonopioid system
Authors: Knisely Janet S. , Hamm Robert J.
Published: January 2005

Previous research has demonstrated that exposure to 90 sec of hind paw shock activates an endogenous pain control system that involves cholinergic sites. The purpose of the present investigation was to examine the development of function of this nonopioid analgesic system. Research on the ontogeny of the cholinergic system suggests that this receptor system exhibits an extended period of postnatal development, with various neurochemical indexes reaching maturity between 30 to 50 days of age. Results revealed that exposure to hind paw shock produced very low levels of analgesia in 10‐ and 28‐day‐old rats. The analgesic response was more evident in 2‐month‐old rats, but the degree of hind paw schock‐induced analgesia was not at its maximum until 3 months of age. Systemic injection of naltrexone had no effect on the degree of analgesia induced by hind paw shock, while a systemic injection of scopolamine significantly attenuated the analgesia displayed by the 28‐day‐old and 2‐ and 3‐month‐old rats. Thus, the neurochemical indexes of cholinergic development overestimated the degree of functional maturity of the endogenous analgesia system activated by hind paw shock.
Acceleration and delay of puberty in female mice via urinary chemosignals: Age of the urine stimulus
Authors: Drickamer Lee C.
Published: January 2005

Five experiments were conducted to test the effects of the age of urine on the acceleration and delay of puberty in female mice resulting from treatment with urinary chemosignals. The chemosignal in the urine of male mice that accelerates female puberty was not affected by remaining exposed to the air at room conditions for up to 7 days, or when dried in air and reconstituted with water. The chemosignal in the urine of grouped, female mice that delays puberty in females and the chemosignal present in the urine of pregnant and lactating female mice that accelerates female puberty were affected to varying degrees by exposure to room conditions; at 5‐to‐7 days exposure the urine samples lost their capacity to delay or accelerate sexual maturation. These results are in agreement with earlier work indicating that the male chemosignal is not volatile, whereas the substances in urine from grouped females and pregnant or lactating females are more volatile. The results also have implications for interpretations of how the urinary chemosignals may affect the population biology of house mice under natural conditions.
Vocal perception: Brain event‐related potentials in a chimpanzee
Authors: Berntson Gary G. , Boysen Sarah T. , Torello Michael W.
Published: January 2005

We describe the first brain event‐related potential (ERP) study of cognitive processes in the chimpanzee. In an extension of our studies on the ontogeny of vocal perception, ERP measures were obtained during the presentation of simple nonsignal stimuli as well as conspecific and human vocalizations. We initially confirmed findings from humans and monkeys of the appearance of a longlatency positivity in the ERP waveform to a rare stimulus in an oddball paradigm. This ERP component is reminiscent of the P3a reported in humans under similar (passive) experimental conditions. We further demonstrated that both conspecific and human vocal stimuli having affective significance also enhanced late positive components of the ERP. These late positive components displayed a predominant fronto–central distribution, with a maxima at Cz. Additionally, responses to adaptively significant vocal stimuli showed a right hemisphere laterality, whereas no significant laterality was observed with the rare stimulus in the oddball paradigm. Results document the feasibility of ERP measures in chimpanzees and their potential utility in the study of the ontogeny and phylogeny of vocal perception. © 1993 John Wiley & Sons, Inc.
Differential effects of SCH 23390 on immobility behaviors in developing rats
Authors: Van Hartesveldt Carol , Meyer Merle E.
Published: January 2005

The effects of a single injection of a dopamine D1 antagonist, SCH 23390, at doses of 0, 0.05, 0.1, and 0.2 mg/kg on three different kinds of immobility behavior were tested in rats of 10, 15, 20, and 30 days of age. Each animal was tested for the dorsal immobility response (DIR), vertical cling catalepsy, and bar catalepsy. A different pattern of results was found for each of the three immobility behaviors. SCH 23390 significantly increased the DIR at each age except 15 days; there was a progressive increase in effect from 10 to 20 to 30 days of age. At the lowest dose, drug‐induced bar catalepsy peaked at 15 days of age and declined at 20 and 30 days of age. The effect of SCH 23390 on vertical cling catalepsy increased with age, plateauing at 20 days. Thus, the developmental pattern of immobility responses to this dopamine D1 antagonist differs with each behavior measured. © 1993 John Wiley & Sons, Inc.
U50, 488 increases ultrasonic vocalizations in 3‐, 10‐, and 18‐day‐old rat pups in isolation and the home cage
Authors: Carden Susan E. , Davachi Lila , Hofer Myron A.
Published: January 2005

Separation‐induced calling in the young of many species can be modulated by the opioid system. Morphine reduces ultrasonic vocalizations (USVs) produced by isolated rat pups, an effect blocked by naltrexone. Central administration of the mu and delta opiate receptor agonists DAMGO and DPDPE reduce USV; kappa receptor agonist U50,488 increases them. We now find that peripheral U50,488 not only boosted calling rates in isolated 3‐, 10‐, and 18‐day‐old rat pups, but also induced calling in pups of these ages tested in the home cage with their littermates, where USVs are seldom heard in nature. U50,488 lowered rectal temperature, although temperature loss and USV were not correlated within drug treatment groups.© 1994 John Wiley & Sons, Inc.
Maternal sensitivity as an external organizer for biobehavioral regulation in infancy
Authors: Spanglar Gottfried , Schieche Michael , Ilg Ursula , Maier Ursula , Ackermann Claudia
Published: January 2005

Recent findings from both animal and human research have clearly demonstrated connections between behavioral coping mechanisms and adrenocortical function. The aim of this study was to address the role of maternal sensitivity as an external organizer of psychobiological function in infants during the first year of life. Forty‐one infants and their mothers were observed during play at 3, 6, and 9 months of age. Age‐specific patterns of relation between maternal sensitivity and infant behavioral organization were found indicating contextual dependence of infant behavior at 3 months and experience‐related behavioral function at 9 months. An affect of maternal sensitivity on adrenocortical function during the free play was demonstrated at 3 and 6 months, because an increase in cortisol was most frequently observed in infants of highly insensitive mothers. The findings indicate the importance of maternal behavior for infant biobehavioral organization.©1994 John Wiley & Sons, Inc.
Plasma cortisol and vocalization responses of postweaning age guinea pigs to maternal and sibling separation: Evidence for filial attachment after weaning
Authors: Hennessy Michael B. , Nigh Carolee K. , Sims Millie L. , Long Stacey J.
Published: January 2005

Postweaning guinea pigs housed with their mother and littermates since birth vocalized more and exhibited greater increases in plasma cortisol levels when placed for 1 hr into a novel test cage alone than they did when tested in the identical fashion with the mother present. These responses were apparent beyond 50 days of age, but had waned by 90 days of age. When tested with a familiar sibling cagemate, postweaning guinea pigs emitted fewer vocalizations than when tested alone but exhibited no less of an elevation of plasma cortisol levels. These results were obtained regardless of whether the subjects had been housed with mother and littermates from birth until the time of testing or with mother and littermates until weaning and then just the single sibling cagemate until the time of testing. The present findings closely approximate those seen in preweaning guinea pigs during tests of maternal and sibling separation, and indicate that guinea pigs can continue to exhibit a specific attachment to the mother beyond the time of weaning. © 1995 John Wiley & Sons, Inc.
Ontogeny of orientation and spatial learning on the radial maze in mices
Authors: Chapillon Pierre , Roullet Pascal , Lassalle Jean Michel
Published: January 2005

The development of the orientation capacities of C57BL/6 mice has been studied on the radial maze in several procedures allowed to dissociate the different types of cues used by the mouse for solving the task with two intersession delays (2 and 24 hr). The results of the first two studies show that performance is independent of intersession delay regardless of the age of the subject. Mice as early as 23 days old obtain good performances when they can develop an algorithmic strategy or when they dispose of both proximal and distal cues during learning. At 37 days of age, however, mice can efficiently solve the radial maze task with distal cues alone. However, in the third experiment, 23‐day‐old mice were able to use distal cues for orientation at the end of the learning session if, at the onset, they also had access to proximal cues. These results suggest that, on weaning, mice use several types of information for task performance and that, as they mature, they turn more often to distal cues for orientation. © 1995 John Wiley & Sons, Inc.
The structure of carbon trioxide
Authors: Pople John A. , Seeger Ute , Seeger Rolf , Schleyer Paul V. R.
Published: January 2005

Open (1) and cyclic (2) singlet forms of CO3 were investigated by means of ab initio calculations. At the highest level of theory employed, MP2/6‐31G* (which includes the effects of electron correlation), 2 was indicated to be much more stable than 1 and thermodynamically stable toward dissociation into CO2 and O(3P). The open form 1 has a long OO bond and can be regarded as a weak dative complex between CO2 and a singlet oxygen atom.
A comparative study of the structure and bonding of HOO, HOS, HSO, and HSS radicals by CNDO/2 and INDO methods
Authors: De B. R. , Sannigrahi A. B.
Published: January 2005

Equilibrium geometries, force constants, barriers to linearity, charge distributions, dipole moments, and electron spin density of HOO, HOS, HSO, and HSS radicals are calculated by CNDO/2 and INDO methods using respectively the original and some recently introduced scheme of parametrization. Three sets of calculations, namely, CNDO/2(sp), CNDO/2(spd), and INDO, are performed, and the results are compared with the ab initio and experimental values, wherever available. A good agreement is obtained for geometry in the case of CNDO/2 (sp) and INDO calculations. The performance of CNDO/2 (spd) calculations in this regard is quite unreliable. The stretching force constants are considerably overestimated by all the methods, while the bending force constants are in reasonable agreement with the ab initio values. With respect to dipole moments, the CNDO/2 values are in better agreement with the ab initio results than the INDO values. In all the cases, the dipole moment vector directions are in complete disagreement with the ab initio predictions.
INDO‐Type calculations on the ground state and various ionic states of transition metal tricarbonyls
Authors: Böhm Michael C. , Gleiter Rolf
Published: January 2005

By means of the ΔSCF and transition operator (TO) methods based on a recently developed INDO extension to the first transition metal series, the first ionization potentials of benzene—chromium tricarbonyl (I), cyclopentadienyl manganese tricarbonyl (II), the iron—tricarbonyl complexes with trimethylenemethane (III), and cyclobutadiene (IV) have been calculated and compared with experimental data. It is shown that the electronic structure of I to IV can be rationalized by Hoffmann's fragment approach in both the ground state and the cationic hole states. Within the series I—IV there are remarkable energy differences in the ground state for MOs derived from the 1a1 and 1e orbitals of the M(CO)3 fragment. The observation that only one band is associated with the ionization events from MOs predominantly localized at the metal site is traced back to large relaxation effects. In the cationic hole states the split of the M(CO)3 fragment orbitals 1a1 and 1e is minute in all four compounds.
Basis set and correlation effects on computed lithium ion affinities of some oxygen and nitrogen bases
Authors: Del Bene Janet E.
Published: January 2005

Basis set expansion and correlation effects on computed lithium cation affinities have been evaluated for the oxygen and nitrogen bases CH3OH, H2CO, CO, CH3NH2, CH2NH, and HCN. The presence of diffuse functions on nonhydrogen atoms is found to be the most important single enhancement of double‐ and triple‐split valence plus polarization basis sets. With the triple‐split basis, enhancement effects are nearly additive. Correlation usually decreases computed lithium ion affinities, with the second order Møller‐Plesset correlation term being the dominant term.
Theoretical studies of O2−:(H2O)n clusters
Authors: Curtiss Larry A. , Melendres Carlos A. , Reed Alan E. , Weinhold Frank
Published: January 2005

The interaction of superoxide ion O2− with up to four water molecules [O2−: (H2O)n, n = 1, 2, 4] has been investigated using ab initio molecular orbital theory. The binding energy of O2−: H2O is calculated to be −20.6 kcal/mol in good agreement with gas phase experimental data. At the MP3/6‐31G* level the O2−:H2O complex has a C2v structure with a double (cyclic) hydrogen bond between O2− and H2O. A Cs structure with a single hydrogen bond is only 0.7 kcal/mol less stable. Interaction of H2O with the doubly occupied π* orbital of O2− is preferred slightly over interaction with the singly occupied π* orbital. Natural bond orbital analysis suggests that both electrostatic and charge transfer interactions are important in anionic complexes. The charge transfer occurs predominantly in the O2− → H2O direction and is important in determining the relative stabilities of the different structures and states. Singly and doubly hydrogen‐bonded structures for the O2−: (H2O)2 and O2−: (H2O)4 clusters were found to be similar in stability and the increase in binding of the cluster becomes smaller as each additional water molecule is added to the cluster.
Ab initio studies of H2PXYH molecules (X, Y = O, S)
Authors: Boatz Jerry A. , Gordon Mark S.
Published: January 2005

Ab initio molecular orbital theory is applied to the study of PO and PS bonding in the hypervalent phosphinic (H2POOH), phosphinothioic (H2POSH), and phosphinodithioic (H2PSSH) acid molecules. Intramolecular proton exchange reactions are followed using the intrinsic reaction coordinate and Self‐Consistent‐Field energy localized orbitals. The PO and PS bonds are characterized via force constants, phosphorus d orbital populations, and localized orbitals and are best described as either normal single bonds or dative bonds augmented by π back donation from the oxygen or sulfur lone pairs. The anions of these acids are also investigated, and they are found to contain only dative bonds to sulfur and oxygen.