bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of species identification in ducklings: IX. The necessity of experiencing normal variations in embryonic auditory stimulation
Authors: Gottlieb Gilbert 
Published: January 2005

AbstractThe domestic mallard duck embryo must be exposed to its embryonic contact‐contentment call at a repetition rate of 4 notes/sec if the neonate is to show the species‐typical preference for the maternal call at its normal rate (3.7 notes/sec) after hatching. Exposing the embryo to the contact call at either 2.1 notes/sec or 5.8 notes/sec is no more effective than no auditory experience at all. To determine if there is a critical period for exposure, embryos were exposed to the 4 notes/sec call either before or after hatching. Both periods proved equally effective provided only that a 48‐hr “consolidation” period was allowed to intervene between stimulation and testing. That is, the birds tested 24 hr after prenatal or postnatal stimulation behaved as if they were not stimulated at all. The present study was undertaken to determine whether the curious requirement for a consolidation period is a normal developmental phenomenon or a consequence of limiting the birds to exposure to a call with an abnormally invariant repetition rate of 4 notes/sec. To that end, embryos were stimulated with the same call as before but at variable rates of 2.1, 4, and 5.8 notes/sec, as happens under normal conditions of development. In this case, the neonates had no need for a consolidation period and showed the species‐typical preference at 24 hr after hatching. Thus the previous results were a consequence of an abnormally narrow range of embryonic auditory stimulation. A 2nd experiment showed that, if the birds' postnatal perception was to be normal, the embryos could not be merely exposed to the rhythmic component of the contact call, but had to experience the characteristic frequency modulation of the call as well.These results indicate that we require surprisingly detailed information about the sensory stimulation present during the usual course of development of our subject species if we are to give an appropriate interpretation to the results of early experiential and critical period manipulations. Knowledge of usual sensory‐stimulative variations has not been a conspicuous feature of developmental psychobiological studies in the past.
Chicken muscular dystrophy: An inherited disorder of flight
Authors: Provine Robert R. 
Published: January 2005

AbstractDystrophic (University of California, Davis, line 413) and normal control (Davis, 1. 412) chicks (Gallus domesticus) between 7 and 49 days old were tested for flight‐related pathology and righting ability. Drop‐evoked lateral flight developed in control chicks between 7 and 13 days. Dystrophic chicks never developed lateral flight. Both dystrophic and control chicks showed drop‐evoked wingflapping on the day of hatching. Also, dystrophic chicks had a normal but slightly higher drop‐evoked flapping rate than controls at 13 days. Thus, the neural circuits that initiated and generated the rate of drop‐evoked wing‐flapping, present in dystrophic chicks at birth, were intact at 13 days, when deficiencies in lateral flight and righting ability were already present. The righting behavior of control chicks was superior to that of dystrophic chicks at all ages from 7 to 49 days.
Pup recognition in Mus musculus: Parental discrimination between their own and alien young
Authors: Ostermeyer Malcolm C. , Elwood Robert W. 
Published: January 2005

AbstractThe responses of male and female mice each presented with a sequence of 4 pups from their own litter, a pup from another litter but of the same age and strain, and finally their own pup were noted. Both sexes spent longer sniffing the alien pup than the preceding own pup regardless of the ages of pups at testing, and more time licking the alien pup on some test days. Young pups (Days 0–3; birth = Day 0) emitted fewer ultrasounds in the presence of a male than a female, but there was no quantitative difference in the vocalizations of own and alien pups. These data indicate that adult mice are able to discriminate between their own and alien offspring; this discrimination appears to be based upon olfactory and possibly gustatory cues rather than auditory ones.
Appetitive instrumental training in preweanling rats: I. Motivational determinants
Authors: Smith Gregory J. , Bogomolny Alice 
Published: January 2005

AbstractTwo experiments tested learning and retention of preweanling rats (10, 15, and 23 days of age) with an appetitive T‐maze spatial discrimination task, using 3 different reinforcers for training (Mother Alone, Mother + Milk, and Milk Alone.) The hypothesis was that immature rats are prepared to select and generate effective hypotheses for learning in an environment bearing some similarity to the home nest prior to their exhibiting similar capacities in other contexts. In Experiment I, we found support for this hypothesis in that 10‐ and 15‐day‐old rats were able to acquire the maze task when reinforced with Mother Alone or Mother +Milk, but not when reinforced with Milk Alone. In Experiment II, we report that 23‐day‐old rats weaned at 19 days postpartum were better at learning the maze task with milk as the reinforcer than littermates raised until training with the dam. We hypothesize that the development of foraging strategies might be necessary for the expression of maze behaviors reinforced with milk alone.
The ontogeny of delta‐9‐tetrahydrocannabinol responsiveness in the rabbit
Authors: Fish Barbara Schneiderman , Consroe Paul 
Published: January 2005

AbstractAn autosomal receissive (thc/thc) in our closed colony of New Zealand White rabbits (Uaz:NZW‐thc) results in nonfatal, behavioral convulsions following intravenous (i.v.) injections of delta‐9‐terahydrocannabinol (THC) and other psychoative cannabinoids of marijuana. The ontogeny of the convulsive response was evaluated in potential THC‐seizure‐susceptible (SS) rabbits from postnatal Days (PN) 15–548. Ages of nonsusceptibility (PN 15–23), partial susceptibility (PN 24–38), and complete susceptibility (PN 39–548) were found. Also, open‐field activity was determined in PN 14–25 THC‐SS and THC‐seizure‐resistant (SR) rabbits. Administration of THC during the seizure‐insensitive period resulted in genotype‐dependent alternations in photocell activity and sprawling.
Species discrimination in infant pigtail macques with pictorial stimuli
Authors: Swartz Karyl B. 
Published: January 2005

AbstractTwo experiments used a visual fixation habituation‐dishabituation paradigm to study the ability of young, socially restricted pigtail macaques to discriminate among adults of 3 macaque species (pigtail, cynomolgus, and stumptail) with pictures as stimuli. The results of the 1st study demonstrated that 3‐month‐old pigtail infants could discriminate among faces of adult females of all 3 species. The 2nd study was methodologically similar to the 1st, with the exception that the face stimuli were presented upside‐down. The results of Experiment II demonstrated no species discrimination, suggesting that the socially relevant discrimination demonstrated in Experiment I was a function of cues unique to the upright face and not a function of abstract cues unique to the upright face and not a function of abstract cues available in both upright and upside‐down facial stimuli.
A developmental look at an auditory illusion: The precedence effect
Authors: Clifton Rachel K. , Morrongiello Barbara A. , Dowd John M. 
Published: January 2005

AbstractInfants aged 2 and 6 months were tested with the precedence effect, an auditory phenomenon involving sound localization. Each infant was tested with two types of stimuli: sound from a single loudspeaker and precedence‐effect sounds produced by the same sound put through two loudspeakers, with one output leading the other by 7 msec. Older infants localized precedence‐effect stimuli as they did single‐source stimuli, indicating that they perceived this phenomenon as expected. Two‐month‐olds turned their heads toward single‐source sounds, but did not localize precedence‐effect sounds, suggesting that that more difficult perceptual task had not been achieved at this age. In general, headturning toward sound proved far more difficult to elicit in younger infants. A click train was ineffective, but a tape‐recorded human voice elicited above‐chance low‐level turning. The developmental changes in auditory behavior are discussed in terms of the rapid growth of the auditory cortex.
Different mechanisms for social transmission of diet preference in rat pups of different ages
Authors: Galef Bennett G. , Kennett Deborah J. 
Published: January 2005

AbstractWe examined the role of simple exposure to a diet in the development of preference for that diet in rat pups 21, 28, 38, and 45 days of age. We found: (1) that 21‐day‐old rat pups exhibited a preference for a diet to which they were simply exposed for 30 min; (2) that 28‐, 38‐, and 45‐day‐old pups failed to exhibit simple‐exposure induced preference for a diet; and (3) that pups at all ages examined, exposed for 30 min to an anesthetized conspecific whose face had been dusted with a diet, subsequently exhibited a preference for that diet. We interpreted these data as indicating that socially‐induced diet preference in 21‐day‐old pups can be explained by effects of simple exposure, while socially‐induced diet preference in older rats cannot. Pups older than 21 days of age appear more sensitive to the social context in which diet‐identifying olfactory cues are experienced than do 21‐day‐old pups.
The effects of maternal isolation and light and feeding cycles on the growth of rat pups
Authors: Anderson Veanne N. , Smith Grant K. 
Published: January 2005

AbstractRat pups were implanted with intragastric catheters and reared in isolation from their dams and siblings from 3 to 18 days postnatally. They were kept in 12:12 LD or DL, constant light, or constant darkness and were fed with one of three feeding schedules: (1) equal amounts of food delivered during the light and dark periods, (2) 65.3% of the food delivered during the light period, or (3) 65.3% of the food delivered during the dark period. At 18 days postnatally the body, spleen, and kidney weights of all isolated pups did not differ from those of their mother‐reared littermates. The isolated pups had smaller cerebellums and forebrains and heavier livers than mother‐reared pups. Heavier body and spleen weights and smaller livers were observed in pups with cyclic feeding. Heavier body and forebrain weights were associated with a predominantly diurnal feeding schedule—the schedule which most closely approximated the natural nursing rhythm. Isolated pups opened their eyes sooner than mother‐reared littermates. These results suggest that interactions between feeding and light cycles may influence growth and development.
Multidimensional perceptual development: Consistency of responses to frequency and intensity in young chickens
Authors: Gray Lincoln 
Published: January 2005

AbstractThe development of consistent responses to multidimensional acoustic stimuli was investigated in newborn chickens. Young chicks suppress their ongoing peeps when they hear a change in an acoustic stimulus, and the amount of that suppression is related to the amount of change. Durations of suppression can thus be interpreted as perceived differences between pairs of stimuli. The suppressions elicited by all possible transitions between pairs of 5 acoustic stimuli that differed in frequency, intensity, and repetition rate were measured at 2 ages. These data were analyzed with a multidimensional scaling program. Interpretable structure is evident in the results from 4‐day‐old chicks to a subset of the stimuli that vary in frequency and intensity. Newborn chicks, in contrast, showed inconsistent responses. Neither age group responded with interpretable structure to stimuli that differed in 3 dimensions. Thus, consistent responses to 2‐dimensional acoustic stimuli emerge over the first few postnatal days. Perceptual dimensions become associated with the physical dimensions of frequency and intensity as animals mature.
Ontogeny of seizure incidence, latency, and severity in genetically epilepsy prone rats
Authors: Hjeresen Dennis L. , Franck Joann E. , Amend Diane L. 
Published: January 2005

AbstractThe Genetically Epilepsy‐Prone Rat (GEPR) is a widely studied model of epileptiform disorders. While there is considerable evidence that neurotransmitter abnormalities contribute to the unusual sensitivity of these animals to seizures, the possibility that seizure susceptibility may reflect developmental changes in the central nervous system has not been fully addressed. In the present study, 91 GEPR‐9 pups were tested for incidence, latency and severity of an audiogenically induced seizure at 6, 9, 12, 15, 18, 21, 24, 27, 28, 29, or 30 days postpartum (1 test per pup) and retested at 60 days. Seizure incidence, latency, and severity were significantly greater on Days 27, 28, 29, and 30 than on all previous days. The first observation of running fits occurred in Day 18 pups and the first evidence of seizures occurred in Day 21 pups. When retested at Day 60, seizure incidence and severity were significantly greater than on initial tests while latency declined. The results suggest that seizure susceptibility in the GEPR‐9 occurs as the result of developmental events in the CNS occurring on or shortly after Day 18 postpartum.
Development of species identification in ducklings. XIII: A comparison of malleable and critical periods of perceptual development
Authors: Gottlieb Gilbert 
Published: January 2005

AbstractThe present experiments sought to determine the relationship of the malleable period—when the mallard duck embryo is most susceptible to alien forms of maternal auditory stimulation—to the critical period, when the embryo must hear its own vocalizations in order to respond normally to the species‐typical maternal call after hatching. It was found that a preference for either a wood duck or a chicken maternal call could be induced in devocalized mallard duck embryos by exposing them to either alien call some time between day 24, 0600 to day 26, 0600 hrs. Further experiments showed the height of the malleable period to be between day 24, 1400 hrs and day 25, 0800 hrs of embryonic development. Since the embryonic critical period for maintenance of the species‐typical maternal auditory preference spans day 24, 0800 hrs to day 26, 0800 hrs, the malleable period for the induction of a preference for species‐atypical maternal stimulation falls inside the critical period. While it is often assumed that malleable and critical periods overlap, this is the first behavioral study to actually demonstrate the temporal relationship of the two periods. It would seem important to further examine malleable and critical periods of development in a broader array of developmental contexts and species to determine whether malleable periods for atypical or abnormal development and critical periods for species‐typical or normal development always coincide.
Human cyclic motility: Fetal–Newborn continuities and newborn state differences
Authors: Robertson Steven S. 
Published: January 2005

AbstractThe spontaneous movement of 41 healthy human newborns was analyzed for cyclic patterns during different behavioral states and also compared to similar data obtained during their last few months of gestation. Spectral analysis was used to identify and quantify the motility cycles, except in quiet sleep, for which the instantaneous frequency of the isolated movements was analyzed. Cyclic motility (CM) was common in all states, and measures of its cyclic organization were similar in the nonsleep states in spite of very large differences in the total amount of movement. During active sleep, CM was weaker and less regular than during the non‐sleep states, but similar to fetal CM during the last month of gestation. Thus cyclic variation in spontaneous motor activity, a basic feature of fetal behavior, is also a nearly constant feature of newborn spontaneous movement. Fetal CM persists relatively unchanged in the newborn during active sleep, and the cyclic organization of newborn movement is independent of the level of motor output.
Continuities in infant memory development
Authors: Hill Wendy L. , Borovsky Dianne , Rovee‐Collier Carolyn 
Published: January 2005

AbstractFifty‐five 6‐ to 7‐month‐old human infants were trained in an operant conditioning procedure, adapted from a procedure developed for 3‐month‐old, in which kicks were reinforced by conjugate movement of a mobile. Retention was assessed in a simple forgetting paradigm (Expt. 1) or in a reactivation paradigm (Expt. 2) with either the training mobile or a different one serving as the retrieval cue. In Experiment 1, retention was tested 1, 7, 14, or 21 days after training. When the training and test mobiles were the same, infants exhibited virtually no forgetting for 14 days, but forgetting was complete by 21. When the training and test mobiles were different, infants exhibited no retention, discriminating the novel mobile for as long as they could remember the contingency. In Experiment 2, when the training mobile was presented as a reminder, the forgetting previously seen after 21 days was alleviated; when a different mobile was the reminder, it was not. These findings reveal that the efficacy of a reminder is predicted by the efficacy of that same stimulus in cuing the original memory 24 hr following training. Although the 6‐month‐olds learned more rapidly and remembered longer than infants half their age, their memory processing was described by the same basic principles.
The ontogeny of drinking evoked by activation of brain angiotensin in the rat pup
Authors: Leshem Micah , Boggan Barbara , Epstein Alan N. 
Published: January 2005

AbstractRenin (1 ng) was injected into the 3rd ventricle of the brain of rat pups at various ages, and their ingestion was measured by weighing them either after 40 min of oral infusion of water or milk while they were away from their dam (off‐dam), or after 40 min of suckling from their dams (on‐dam). Beginning at 3–5 days of age, renin increased ingestion of milk and water off‐dam. After 15 days of age, milk ingestion off‐dam was no longer increased by renin, but intake of water continued to be evoked. In contrast, renin did not increase intake by suckling at any age. These findings reveal that the adult characteristics of the dipsogenic action of the renin–angiotensin system in the brain emerge at 15 days, at which age the increased intake becomes entirely specific for water. This finding confirms the precocity of the neural controls of drinking in the rat and shows that, like the controls of independent feeding, they are dissociated from those of suckling. It adds support to the idea that the neonatal mammalian brain contains separate neurological systems for suckling and for independent ingestion.
Stimulus attributes of reactivated memory: Alleviation of ontogenetic forgetting in rats is context specific
Authors: Richardson Rick , Riccio David C. , McKenney Michael 
Published: January 2005

AbstractNumerous studies have shown that ontogenetic forgetting (infantile amensia) can be alleviated by a number of different types of reminder treatment. The present study extends the information about the alleviation of infantile amnesia by examining the “content” of the reactivated memory. Toward tis purpose, one attribute of memory (environmental context) was examined in rats tested either shortly after training (preamnesic) or after 1‐week retention interval. For the latter, a reactivation treatment was used to reverse infantile amnesia. At both intervals, a context shift resulted in impaired performance of a conditioned fear response. These findings demonstrate that environment context is an important component of the originally encoded memory as well as the reactivated amnestic memory. The implications of these results for both the reactivation of memory and general memory processes are discussed.
Ontogeny of susceptibility to experimental febrile seizures in rats
Authors: Hjeresen Dennis L. , Diaz Jaime 
Published: January 2005

AbstractTwo experiments were conducted using microwave hyperthermia (MHT) to induce seizures among limited numbers of Long‐Evans rat pups. The MHT model of febrile seizures eliminates several methodological complications inherent in previous animal models of the disorder. In Experiment 1, rat pups were rendered hyperthermic with MHT or were sham‐irradiated on Days 11, 13, 15 or 17 postpartum. The results indicate a statistically significant decline in seizure susceptibility with age. In Experiment 2, rats were subjected to either single or multiple hyperthermic episodes on Days 11, 13, 15, or 17 postpartum. The results indicate an increase in susceptibility to seizures attributable to prior seizure history. In both experiments, seizures were induced with increases in rectal temperature of 1 to 3°C. The results parallel many clinical features of febrile seizures and argue the efficacy of the MHT model.
Fetal gender and aggression in pregnant stumptail monkeys (Macaca arctoides)
Authors: Nieuwenhuijsen K. , Slob A. K. , De Neef K. J. 
Published: January 2005

AbstractAgonistic behaviors of pregnant female stumptail monkeys, members of a large, well‐integrated group continuously living together, were studied during 480 observation hours (over 32 months). A total of 28 pregnancies of 20 females occurred, resulting in 12 male and 16 female live infants. The main finding was a significant decline in aggression, both received and performed, during the course of pregnancy. There was no clear unequivocal effect of fetal gender on aggressive behavior of the mothers‐to‐be.
Adrenocortical activity and behavioral distress in human newborns
Authors: Gunnar Megan R. , Connors Joan , Isensee Jill , Wall Leigh 
Published: January 2005

AbstractThe association between behavioral distress and adrenocortical activity was examined in two experiments with human newborns. In Experiment 1, behavioral and adrenocortical responses to 4 events (circumcision, blood sampling, weighing and measuring, and discharge examination) were compared using a between‐subject design. All 4 events elicited fussing and crying and elevations in plasma cortisol; however, differences in behavioral distress among conditions did not reliably predict differences in plasma cortisol. In Experiment 2, nonnutritive sucking was used to effectively reduce behavioral distress, but was not associated with a reduction in the adrenocortical response to stimulation. Finally, using data from both experiments, correlations were computed between behavioral distress and cortisol. Both positive and negative associations were found as a function of the type of stressor and the biomedical status of the newborn.
Ontogeny of polycose and sucrose appetite in neonatal rats
Authors: Vigorito Michael , Sclafani Anthony 
Published: January 2005

AbstractRat pups 3 to 15 days of age were infused with sucrose or Polycose solutions (.03 or .3 M) through oral cannulas and their solution intake, mouthing behavior, and general locomotor activity were recorded. Overall, the pups displayed similar ingestive responses to Polycose and sucrose. They discriminated between .3 M sucrose and water as early as 6‐days of age, and between .3 M Polycose and water as early as 9‐days of age. However, at the .03 M concentration the pups responded to Polycose before they responded to sucrose. The results confirm previous reports that rat pups have an unlearned preference for sucrose and demonstrate that a similar preference exists for starch‐derived polysaccharides. The Polycose appetite displayed by the neonatal rats is consistent with results obtained with adult animals which suggest that rats have taste receptors for starch‐derived polysaccharides as well as for sugars.