bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of auditory stimulation on heart rate in premature infants as a function of level of arousal, probability of CNS damage, and conceptional age
Authors: Schulman Carol A. 
Published: January 2005

AbstractIn 2 experiments, heart rate responses of newborn infants to an auditory stimulus as a function of sleep vs wakefulness, probability of perinatal impairment of the central nervous system, and developmental level were compared. All subjects were studied under standard conditions, in their own incubators, using an 80 dB (re 0.02 dynes/cm2) low‐frequency buzzer of 3‐sec duration. Heart rate responses were averaged over 10 trials for each subject in each state. In the first study, which compared the responses of high‐ and low‐risk subjects of 1800 gm or greater weight, it was found that there was no difference between the groups in the response during sleep; or greater weight, it was found that there was no difference between the groups in the response during sleep; during wakefulness, however, a significant difference in the direction of response was found. High‐risk subjects accelerated, as in sleep, whereas low‐risk subjects decelerated. In a developmental study of 4 small premature infants, it was found that the direction of the waking heart rate response changed from acceleration to deceleration at about 35 to 36 weeks conceptional age.
Studies of undernutrition in the young rat: Methodological considerations
Authors: Plaut S. Michael 
Published: January 2005

AbstractThree techniques are generally described as creating a state of undernutrition in the young rat: large litter size, periodic mother‐litter separation, and early weaning. Evidence from studies of maternal behavior and early experience suggests that many of the effects seen in „nutritional deprivation”︁ experiments may be due, in part, to the social, thermal and sensory deprivation coincident with maternal deprivation, or to other factors (such as handling) which are often confounded with maternal deprivation. These other variables must be systematically accounted for before assumptions can be made about the effects of undernutrition per se.
Infantile stimulation and ultrasonic signaling: A possible mediator of early handling phenomena
Authors: Bell Robert W. , Nitschke Werner , Gorry Thomas H. , Zachman Thomas A. 
Published: January 2005

AbstractPeromyscus maniculatus bairdi were either handled or not handled daily during the first 10 days of life. Handling consisted of removing the infant mice from the litter, placing them in small individual compartments where they remained for 3 min, and then replacing them in the nest. Immediately following the handling, simultaneous video and audio recordings were made of nest behavior for two 30‐sec recording sessions. The nonhandled controls were treated comparably except that pups were never removed from the nest. Handled litters differed from nonhandled in terms of the average number of signals per recording session (132.5 vs. 16.5), the average signal duration (0.108 sec vs. 0.045 sec), and the average peak frequency of signals (22.216 kHz vs. 11.990 kHz). During those recording sessions in which no vocalizations were detected no physical interaction appeared between the mother and the infants. During all sessions in which vocalizations were emitted the mother was retrieving and grooming the infants. The data suggest a possible interpretation of the effects of early handling in terms of modified mothering, medidiated by modified vocalizations of infant mice as a function of the handling.
Senile web patterns in Uloborus diversus (Araneae: Uloboridae)
Authors: Eberhard William G. 
Published: January 2005

AbstractElderly females of the spider Uloborus diversus (Uloboridae) spin webs which are different in various respects than those spun earlier in their lives. “Senile” virgins' webs differed from those of “senile” non‐virgins' in several characteristics and in some ways resembled those of first instar nymphs.
Reinforcement value of electrical brain stimulation in neonatal dogs
Authors: Bacon W. Edward , Wong Ira G. 
Published: January 2005

AbstractElectrical brain stimulation in puppies during the first week of life was correlated with crawling from a demonstrably preferred to nonpreferred tactual stimulus. Preferences changed when the structures stimulated were the same as reward areas in adult mammals, thus demonstrating that electrical stimulation in the infant brain has positive reinforcement value.
Mirror self‐image reactions before age two
Authors: Amsterdam Beulah 
Published: January 2005

AbstractThe behavior of 88 children between 3 and 24 months was observed before a mirror, using an objective technique to examine the child's awareness of the image as his own. The results indicate the following age‐related sequence of behavior before the mirror: the first prolonged and repeated reaction of an infant to his mirror image is that of a sociable “playmate” from about 6 through 12 months of age. In the second year of life wariness and withdrawal appeared; self‐admiring and embarrassed behavior accompanied those avoidance behaviors starting at 14 months, and was shown by 75% of the subjects after 20 months of age. During the last part of the second year of life, from 20 to 24 months of age, 65% of the subjects demonstrated recognition of their mirror images.
Environmentally induced changes in the dimensions of the rat cerebrum: A replication and extension
Authors: Walsh Roger N. , Cummins Robert A. , Budtz‐Olsen Otto E. 
Published: January 2005

AbstractIn previous reports exposure to 80 or 90 days of environmental complexity induced a significant increase in the length of the rat cerebrum, whereas 30 days' exposure induced changes which failed to reach significant levels. In the present study after 30 days of differential rearing, cerebral length was 1.2% (p < .005) greater in brains from the enriched animals; the region contributing to this increase lay between the anterior pole and the point of greatest cerebral width. Measurements of cerebral width and brain weight failed to show any significant change, but the body and adrenal weights of the isolated rats were 19.9% (p ≤ .02) greater, respectively, than those of their littermates reared in environmental complexity. However, the ratios of adrenal weight to body weight did not differ significantly between groups.
An investigation of various egg‐opening techniques for use in avian behavioral embryology
Authors: Oppenheim Ronald W. , Levin Hinda L. , Harth Marshall S. 
Published: January 2005

AbstractThe effects of various egg‐opening techniques, including the Kuo Vaseline technique, upon survival, hatchability, and embryonic behavior have been experimentally evaluated in the present study. The major aim was to develop a technique that could be used for long term behavioral studies throughout most of incubation. The Kuo Vaseline technique was found to provide the poorest results in terms of survival and hatchability: none of the embryos in eggs opened by this technique hatched. Two techniques, however, did provide adequate survival and hatchability such that they could easily be used for behavioral observation of the chick embryo from the 2nd day of incubation until hatching. These latter techniques involved partial removal of the inner shell membrane in the air‐space; or the placement of a lateral window over the embryo along the side of the egg. Of all the techniques evaluated only the Vaseline technique resulted in a significant modification of the embryos' movements.
Hypothyroidism and the maturation of the hypothalamo‐hypophyseal‐adrenal axis
Authors: Meserve Lee A. , Leathem James H. 
Published: January 2005

AbstractRats were made hypothyroid by feeding .25% thiouracil in a semipurified casein diet to mothers from the first day of pregnancy through lactation. At 15 days of age, concentrations of adrenal and serum corticosterone were comparable in euthyroid and hypothyroid young, suggesting a basal ACTH release. Ether stress, however, failed to elicit an increased synthesis and release of corticosterone in the hypothyroid rat, but was effective in the euthyroid animal. Exogenous ACTH, on the other hand, did induce corticosterone synthesis and release in hypothyroid and euthyroid rats, indicating a functional adrenal gland. Thus, neonatal hypothyroidism appears to influence the hypothalamus. The retarded maturation of this axis may play a role in behavioral deficiencies seen in hypothyroid animals.
Mother‐infant separation in squirrel monkeys living in a group
Authors: Jones Byron C. , Clark Dennis L. 
Published: January 2005

AbstractTwo female and 3 male infant squirrel monkeys were separated from their mothers at a mean age of 169 days. All had been group reared. The experiment entailed three 5 day periods: (1) preseparation; (2) separation; and (3) reunion. During the experiment, each infant was observed for 10 min per day. Frequency and duration measures were recorded for activity play, locomotion, object manipulation, and disturbance. Social behaviors recorded were contact play, mixed play, competition play, sex play, affiliation, display, and aggression.Changes noted during separation were depression of activity play, contact play, mixed play, object manipulation, and sex play. Affiliative behaviors and locomotion increased during separation.After reunion, locomotion and affiliation returned to baseline levels while contact play, mixed play, and object manipulation remained depressed.
Brain weight changes resulting from enriched rearing conditions: A diallel analysis
Authors: Henderson Norman D. 
Published: January 2005

AbstractHousemice from 6 inbred lines and their F1 crosses were reared in standard or enriched laboratory cages. A genetic analysis of brain and body weights indicated a significant directional dominance effect toward larger brain in F1 crosses among enriched animals only, even when adjustments for body weight were made. The proportion of additive genetic variance was greater in standard caged animals than in enriched animals. Maternal effects played a small but significant role in influencing brain weights apart from those indirectly caused by body weight effects. The use of laboratory reared animals for genetic studies is questioned when environmental influences are known to have a strong effect on the character being studied, and the results are to be used to make inferences concerning the adaptive significance of the character.
Straight‐alley escape behavior in infant mice: Effect of shock intensity
Authors: Nagy Z. Michael , Misanin James R. 
Published: January 2005

AbstractSeparate groups of Swiss‐Webster mice between 5‐15 days of age received 25 training trials in a straight‐alley escape task at 1 of 4 shock intensities, ranging from .1‐.8 mA. An increase in shock level led to better escape performance at all ages, although the amount of improvement varied directly as a function of age. The results supported earlier work suggesting that the competing response measure was the most useful index of improved escape behavior at the early ages. Running speeds did not indicate improved within‐session escape performance at any age or shock level, although speeds clearly reflected maturational and motivational differences between groups.
Novelty induced changes in spontaneous alternation by infant and adult rats
Authors: Egger Garry J. 
Published: January 2005

AbstractPreviously, preweaned rats have been shown to perseverate rather than alternate choices of goal arms over 2 trials in a T‐maze. In this study 16‐day old animals were successfully induced to increase their rate of alternation to chance level in the present experiment by increasing the novelty value on Trial 2 of the previously unchosen goal arm. Similarly, 100‐day old rats were encouraged to decrease their level of alternation by enhancing the novelty value of the previously chosen arm. An explanation for these findings was offered in terms of the escitatory and inhibitory effects of a stimulus, and the gradual development of inhibition in ontogeny.
Maternal vitamin A excess during the early fetal period: Effects on learning and development in the offspring
Authors: Hutchings Donald E. , Gibbon John , Kaufman Mavis A. 
Published: January 2005

AbstractPregnant rats were administered a teratogenic dose of vitamin A excess on Days 14 and 15 of gestation. Intubation controls received the vehicle alone; nontreated mothers were not disturbed; all groups were fostered to untreated mothers after birth. Treated offspring showed a generalized retardation in growth as evidenced by delayed onset of fur growth, eye‐opening, and reduced body weight. Treated subjects acquired the operant S+, S− discrimination during adulthood significantly slower than the controls because of a failure to inhibit responding in S−. Although their proportion of S+ responding eventually reached the level of the controls, they failed to acquire comparably long S− latencies, even during 40 sessions when S− responding was punished with shock. The treated rats evidently were less able to inhibit responding in the signal which indicated nonreinforcement. Histological examination of the brains revealed that the maternal vitamin A excess produced an overall reduction in offspring brain size with obvious microcephaly occurring in 1 animal.
The effects of premature delivery on subsequent development of the rat
Authors: Grota Lee J. , Ambruso Dan 
Published: January 2005

AbstractDelivery of rat fetuses 18 hr prematurely results initially in decreased body weight and delayed development of the negative geotropic response compared to full‐term infants. At adulthood, prematurely delivered rat fetuses were less emotional than full‐term controls, but did not differ in weight, learning, and susceptibility to gastric erosions.
Effect of genotype and practice upon behavioral development in mice
Authors: Fuller John L. , Herman Barbara H. 
Published: January 2005

AbstractPsychomotor development from birth to 18 days of age was observed in 3 lines of mice selected for high (H), medium (M), and low (L) brain weight. Litters were cut to 8 at birth and half of the individuals randomly assigned to a practiced group tested daily; the remainder were assigned to a nonpracticed group and were tested only on selected tests on the day at which their littermates met a predesignated criterion. Significant differences between the lines were found in open field activity, balancing on a rotorod, age of eye‐opening, and edge avoidance. The H‐line was generally more advanced than either M or L. On some measures, righting for example, no strain variation was found. The effects of practice were usually significant, but did not abolish strain differences.Most research on the behavioral effects of genetic variation in the nervous system has been concerned with effects of mutant genes producing major disruption of developmental patterns. Our results indicate that genes affecting the rate and amount of normal brain growth also influence behavioral development. Genes of this type may be responsible for some of the individuality of behavioral phenotype found in natural populations.
Mirror image and self‐recognition in young human infants: I. A new method of experimental analysis
Authors: Papoušek Hanuš , Papoušek Mechthild 
Published: January 2005

AbstractThe infant's responses to his mirror image have been viewed as indices of self'recognition, but a lack of experimental evidence has caused contradictory conclusions on the beginning of self'recognition. The authors suggest that infants may respond to several factors in the mirror image: eye'to'eye contact, contingency of the image on their own behavior, a smiling face, another babyish being or another human being in general, and the identity of the image with their concept of self. A method for the study of these factors is described. The mirror image was replaced with a televised self‐image which was presented simultaneously with another matching image in a 2‐choice preference design. The discriminant variables between both images equate individual factors of the mirror image in individual modifications of the method. In this pilot study of eleven 5‐month‐old infants, the basic methodological questions were solved, and the first attempt was made to evaluate the roles of eye‐to‐eye contact and of mirror‐image contingency.
Escape learning: Acquisition and extinction rates as a function of age in rats
Authors: Egger Garry J. 
Published: January 2005

AbstractAn asymptotic measure of acquisition incorporating both escape latencies and competing responses (180° turns away from the goal box) was used to compare escape learning over ages in rats. Rats aged 24, 50, and 100 days did not differ in the number of trials required to reach acquisition as determined by this criterion. However, the youngest group required significantly more trials than either of the older groups to extinguish responding in this situation. They also performed significantly more competing responses than the older group in the early stages of acquisition.
Ovarian influences on the development of sexual behavior in neonatally androgenized rats
Authors: Hendricks Shelton E. , Duffy John A. 
Published: January 2005

AbstractFemale sexual behavior was studied in male and female rats. Males were castrated on the day of birth (Day 1); some received ovarian implants at that time; others were injected on Day 3 with oil, 5 μg testosterone propionate (TP), or 50 μg TP. Females were ovariectomized at birth, 20, or 60 days of age; on Day 3 all were injected with oil, 5 μg, TP, or 50 μg TP. Prepuberal ovarian tenancy in females tended to counteract the effects on sexual receptivity of TP administered during neonatal life. In males ovarian implants facilitated female sexual behavior at adulthood in oil‐injected animals, but did not significantly influence the effect on neonatally injected TP.
Infant development in two prosimian species: Greater galago and slow loris
Authors: Ehrlich Annette 
Published: January 2005

AbstractInfant development in 2 prosimian species‐‐greater galago and slow loris‐‐was studied in 2 ways. First, the initial appearance and/or the eventual disappearance of various simple motor behaviors in infants was recorded. Second, the time spent by mothers and infants in contact, near, and away from each other was measured during the first 10 weeks of life. The aim was to see how the 2 sets of measures relate to each other and also to compare the 2 prosimian species with each other and with other primates. The results showed that: (1) contrary to the views advanced by some authors, the speed with which simple motor behaviors attain the adult form is not related in any consistent way to phyletic status, age at which sexual maturity is reached, or the mother's ability to provide manual support for her infant; (2) the pattern of mother‐infant interaction is more variable in prosimian than in anthropoid primates; and (3) the disappearance of involuntary foot‐grasping coincides with the initiatior of infant independence from the mother.
Critical periods in the organization of systems
Authors: Scott J. P. , Stewart John M. , De Ghett Victor J. 
Published: January 2005

AbstractThe general theory of critical periods applies to organizational processes involved in the development of any living system on any level of organization and states that the time during which an organizational process is proceeding most rapidly is the time when the process may most easily be altered or modified. Complex organizational processes involving 2 or more interdependent subprocesses may show 1 to several critical periods, depending on the time relationships of the subprocesses. The nature of the relationships between interdependent processes operating on different levels is again dependent on time and is a more meaningful formulation than that of the old “innate‐acquired” dichotomy. These theoretical considerations lead to the conclusion that understanding a critical‐period phenomenon rests on analyzing the nature of the organizational process or processes involved. An example is given in a review of research on the critical period for primary socialization (social attachment) in the dog. Evidence that attachment has taken place consists of discriminative behavior in relation to familiar and unfamiliar objects and rests on a minimum of 3 processes: (1) organization of the separation distress response; (2) visual and auditory sensory capacities; and (3) long‐term associative memory capacities. Once these capacities are developed, the overall attachment process proceeds very rapidly (the critical period for such attachment). Thus the critical periods for the organizational subprocesses precede or slightly overlap that for the overall process. Deeper analyses of these processes must rest on neurophysiological research. The theory of critical periods is a general one that should apply to any developmental organizational process which proceeds at grossly different rates at different times.
Following and visual imprinting in ducklings across a wide age range
Authors: Brown Robert T. 
Published: January 2005

AbstractDucklings ranging in age from 20–125 hr were exposed to a moving silent object in an open circular apparatus until a criterion of 300 sec of following was met. All duckings met the criterion, and age did not correlate with the time required. In subsequent choice tests most ducklings approached the imprinting object over a novel object, and age did not correlate with choice behavior. Results indicate that imprinting can occur over a fairly wide age range, and that the traditional critical period for imprinting may, in part, be an artifact of laboratory methods.
Impairment of conditioned active avoidance in adult rats given corticosterone in infancy
Authors: Olton David S. , Johnson Craig T. , Howard Evelyn 
Published: January 2005

AbstractIntensive corticosterone treatment given to rats during the 1st postnatal week irreversibly decreases DNA accumulation in the cerebrum and cerebellum. After such hypercorticism in infancy rats were tested as adults in 2 conditioned active avoidance tasks. In comparison with litter‐mate controls, the treated rats were impaired in the acquisition of 2‐way active avoidance but not in the acquisition of 1‐way active avoidance. These data are consistent with other observations suggesting a hyperresponsiveness or hyperemotionality following corticosterone treatment in infancy.
Developmental changes in pre‐adult behavior in confined colonies of golden hamsters
Authors: Goldman L. , Swanson Heidi H. 
Published: January 2005

AbstractEight litters of hamsters living in a large enclosure were observed from birth to 120 days. For the first 65 days each litter was confined to a separate compartment. Basic motor coordination was reached by the 3rd week. Marking was seen during the 6th week when males began to mount their mothers sexually, but lordosis was not seen in female pups before the 7th week. Fighting appeared at this time with the females being the more aggressive.At 65 days the litters were combined into 2 groups of 4. A gradual shift followed in the relative aggressiveness of the sexes. Females, which had previously initiated over 90% of attacks, became less aggressive, whereas attacks by males increased to the former female level. This unusual behavior for hamsters, where females are normally dominant, may have been due to crowding. Also, severe disruption of maternal behavior occurred with marked infanticidal tendencies.