bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of age and sex on the behavior of rats deprived of the rearing response
Authors: Syme Lesley A. 
Published: January 2005

AbstractRearing on the hind legs, one component of “general activity,” was restricted in male and female rats both before (25 days) and after (50 days) the development of this response. In contrast to previous restriction studies the animals were kept in groups and allowed free locomotor activity in the cage environment. After 8 weeks, open‐field testing showed that selective restriction decreased the frequency of rearing behavior, particularly unsupported rearing which requires physical coordination and balance. Effects were greater for females (which usually rear more than males) and for animals restricted at weaning (25 days).
Effect of mother on the development of aggressive behavior in rats
Authors: Flandera V. , Nováková V. 
Published: January 2005

AbstractYoung rats 23 days of age (Wistar strain) that are offspring of aggressive parents will attack mice. They kill them, however, only if the mother has already killed mice in their presence. Rats 30 days of age will kill mice spontaneously without any previous exposure to killing. The occurrence of muricide activity in young rats of this age is the same as in the adult population. If offspring of aggressive parents are reared by nonaggressive foster mothers from birth, they will not exhibit the muricide reaction at 30 days. In adulthood, however, the reaction appears to the same extent as in the offspring of aggressive parents reared by aggressive mothers. If the descendants of nonaggressive parents are reared by aggressive foster mothers from birth, 64.7% of them will kill mice at the age of 30 days. This aggression is retained in equal intensity during adulthood and cannot be attributed to specific learning in that the mothers have never encountered a mouse in the presence of their foster young.
Olfactory, thermal, and tactual influences on infantile ultrasonic vocalization in rats
Authors: Oswalt Gaylon L. , Meier Gilbert W. 
Published: January 2005

AbstractThe amount of time infant rats 3–13 days old spent emitting ultrasounds was greater when pups were placed in an empty dish than when placed in a dish containing clean bedding or soiled bedding from the nest. Pups from 5–13 days of age vocalized more when on the clean bedding than when on the soiled bedding. When placed on cloth covered dishes, pups vocalized most to the empty dish and least to the dish containing soiled bedding. The odor of clean bedding elicited less ultrasonic vocalization than the odor of the empty dish only when pups were less than 7 days old. Pups vocalized more to room temperature than to heated conditions. The results indicate that olfactory, tactual, and thermal nest cues influence infantile ultrasonic vocalization in the rat.
Early life undernutrition and aggression in two mouse strains
Authors: Randt Clark T. , Blizard David A. , Friedman Eitan 
Published: January 2005

AbstractEarly undernutrition was shown to be correlated with increased aggression in adult mice after isolation. This was significant in numbers of fights and shorter latency to fight in the DBA/2J strain. Lower 5HIAA in the brain after pretreatment with a monoamine oxidase inhibitor was found in the undernourished group.
Duration of early visual experience and visual cliff behavior of chicks
Authors: Kaufman Lynn W. 
Published: January 2005

AbstractVisual cliff behavior was studied in 120 chicks as a function of 22, 46, 70, 94, or 118 hr of rearing in a deep or shallow environment. Preference for the deep side of the visual cliff increased directly with duration of depth‐rearing but was uninfluenced at any duration of shallow‐rearing. Although qualitative differences existed in the behaviors of those shallow‐ and deep‐reared chicks which crossed the cliff, the loss of depth avoidance by the latter group appeared to be specific to the rearing and testing apparatus.
The development of passive and active avoidance learning in the cat
Authors: Davis Joel L. , Jensen Robert A. 
Published: January 2005

AbstractKittens of 25 and 50 days of age were tested on a passive avoidance task in a 2‐compartment black‐white shuttle box. Latency t o enter the dark side of the box was the same for both groups on Day 1, but the latency to enter the dark side on Day 2 was much shorter for the younger kittens. Other kittens were trained in a step‐up active avoidance task also at 25 and 50 days of age. No differences were found in active avoidance performance between the younger and older animals, indicating that active and passive avoidance tasks may possibly reflcct separate devclopmcntal proccsses that mature at different rates in the cat.
Effects of early experience on the metabolism and production of corticosterone in rats
Authors: Grota Lee J. 
Published: January 2005

AbstractRats were handled for 3 min daily for 3 weeks before or after weaning or were left totally undisturbed. At 80 days of age, animals from each group were selected for corticosterone half‐life determination. Adrenal tissue from the remaining animals was incubated in vitro in the presence or absence of ACTH. Handled and unmanipulated animals did not differ in half‐life or in adrenocortical output. These data do not support the hypothesis that the reduced adrenocortical reactivity that results from manipulating animals is due to either the metabolism of corticosterone or the response of the adrenal cortex to ACTH.
The effects of prenatal psychological stress on the sexual behavior and reactivity of male rats
Authors: Masterpasqua Frank , Chapman Robert H. , Lore Richard K. 
Published: January 2005

AbstractMale offspring of prenatally stressed rats showed low levels of copulatory behavior during a series of brief tests with estrous females but successfully impregnated female cagemates during long term tests of breeding effectiveness. Sexual performance on the short term tests was inversely related to open field activity with the offspring of prenatally handled mothers exhibiting more sexual behavior and less open field activity. These results support the notion that prenatal stress influences both the sexual behavior and emotional reactivity of male offspring. Deficits observed during short term tests of breeding effectiveness appear to be reversible under optimal conditions.
The development of the EEG in the rat
Authors: Gramsbergen Albert 
Published: January 2005

AbstractThe development of the electroencephalogram EEG and, especially, behavioral state‐specific EEG patterns was studied in white and black hooded rats of the Lister strain, aged 9‐30 days. Movements of the rat were recorded and the behavioral state was monitored by means of a push‐button device. The EEG was collected when the rat was in State 1 (regular respiration, absense of movements, and, after the 14th day when the rat eye opens, eyes closed, State 2 irregular respiration, continual occurrence of twitches, and, after the 14th day, eyes closed, and in State 4 irregular respiration, presence of gross body movements, and, after the 14th day, eyes opened).The EEG of rats on the 9th and 10th day did not reveal behavioral state‐specific patterns. The amplitudes of the EEG were low and only low frequencies occurred. Between the 10th and 13th day an EEG pattern specific for State 1 containing high amplitudes developed. From the 14th day onwards, spindles frequencies from 14‐18 Hz occurred in the EEG during State 1. From the 14th day onwards, the EEG from the visual cortex during State 2 showed a regular and continually occurring 5‐Hz rhythm. Bursts with 5‐Hz waves were recorded from the visual cortex only intermittently during State 4. The EEG frequencies during the bursts varied between 5 and 7 Hz from the 17th day onwards. Computer analysis of the amplitude distributions showed a considerable increase in the power after the 10th day. The analysis of the frequency spectra indicated that the power increase occurs especially in the higher frequencies of the EEG signal. Visual analysis as well as computer analysis of the EEG did not reveal systematic changes in the EEG after the 18th day when the EEG was similar to that recorded at older ages.
Female perception of cowbird song: A closed developmental program
Authors: King Andrew P. , West Meredith J. 
Published: January 2005

AbstractTo investigate the modifiability of the brown‐headed female cowbird's (Molothrus ater ater) response to male song, we reared M.a. ater females with either M.a. ater or M.a. obscurus males, whose songs differ in geographic origin. The females were later tested for their responsiveness to playbacks of M.a. ater and M.a. obscurus song. Rearing with M.a. obscurus males had no effect on the female's preference for her native song variant, suggesting a closed program for receptive development. The data on song perception are contrasted with those previously obtained for male production and indicate different constraints on song perception as opposed to song production.
Olfaction mediates developmental transition in the altricial newborn of selected species of mammals
Authors: Rosenblatt Jay S. 
Published: January 2005

Abstract“We should compare the manner in which orientation develops, first to the mother and later to an expanding environment. It would be interesting to carry out detailed comparisons of the ontogeny of such adjustments in blind‐born mammals such as the dog in comparison with mammals that have vision at birth–ungulates, for example. Important changes occur in the orientation of blind‐born mammals in the presight period, which we do not as yet have the techniques to investigate adequately.”T.C. Schneirla (1954)
Acoustic correlates of individuality in the cries of human infants
Authors: Gustafson Gwene E. , Green James A. , Tomic Tamara 
Published: January 2005

AbstractThe acoustic features that differentiate the cries of individual human infants were examined in this study. A recognition task, performed by 400 nonparent adults, was used to classify twenty 30‐day‐old infants as easy or difficult to recognize on the sole basis of their tape recorded cries. The cries of easy‐ vs difficult‐to‐recognize infants were then compared on measures of duration, fundamental frequency, peak frequency in the spectrum, signal‐to‐noise ratios, and energy in selected frequency bands. The results indicated that each of these measures differentiated the cries of easy‐ vs difficult‐to‐recognize infants. Such redundancy should make the cry robust to degradations of selected acoustic parameters, thus enhancing its ability to carry information about individual identity across distances.
Appetitive conditioning in neonatal rats: Conditioned ingestive responding to stimuli paired with oral infusions of milk
Authors: Johanson Ingrid B. , Hall W. G. , Polefrone Joanna M. 
Published: January 2005

AbstractComponents of rat pups' ingestive responses to orally infused milk came to be elicited by a novel odor conditioned stimulus (cedar) that had been repeatedly paired with milk infusions (Experiment I). Pups responded specifically to one odor, and they did not generalize their conditioned responding to either another odor or an unscented airstream (Experiment II). Ingestive responses could also be conditioned to a vibrotactile CS paired with milk, although levels of conditioned responding were lower than were obtained with an odor CS (Experiment III). Pups' internal state determined the effectiveness of training, in that pups that were removed from their dam for 24 hr showed reliable conditioned responding, while nondeprived pups and dehydrated pups did not (Experiment IV). Finally, pups showed retention of conditioned responding for at least several days after training (Experiment V).
Haloperidol differentially potentiates tonic immobility, the dorsal immobility response, and catalepsy in the developing rat
Authors: Meyer Merle E. , Smith Ronald L. , Van Hartesveldt Carol 
Published: January 2005

AbstractThe effects of a single subcutaneous injection of haloperidol (1 or 10 mg/kg) or the vehicle solution on three kinds of behavioral inhibition were investigated in rats of 10, 15, and 20 days of age. The behaviors measured were tonic immobility, a response induced by lacing an animal on its back supported by a V‐shaped trough; the dorsal immobility response, which can be elicited in young rodents by grasping the skin of the dorsal surface of the neck and lifting the animal into the air; and catalepsy, a form of immobility in which animals remain in unusual postures but are capable of righting themselves, and which can be elicited by drugs which block dopamine receptors. Haloperidol (10 mg/kg) significantly potentiated the duration of tonic immobility only at 10 days of age; potentiated catalepsy at all age levels, but significantly less in the 15‐day‐old rats than in the 10‐ or 20‐day‐old rats; and potentiated the duration of the dorsal immobility response in the 10‐ and 20‐day‐old animals but not in the 15‐day‐olds. These results are discussed with respect to the development of neurotransmitter systems in the brain.
Familiar contextual odors promote discrimination learning in preweanling but not in older rats
Authors: Wigal Tim , Kucharski David , Spear Norman E. 
Published: January 2005

AbstractFor rats 16‐ or 28‐days‐old postnatal, we tested the source of the facilitation in instrumental learning provided by odors from home nest materials. Three experiments confirmed that acquisition of a spatial discrimination (to escape footshock) was facilitated not only by the presence of typical nest odors in the training context, but also by the presence of a non‐rat odor (banana) to which the animals had been familiarized for 4 hr/day for 7 days. There was a borderline tendency for a similar facilitation after familiarization to the latter odor for only 10 min. These effects occurred for a similar facilition after familiarization to the latter odor for only 10 min. These effects occurred for rats 16 days postnatal but not for those 28 days old. The experiments also confirmed that the prior exposure to non‐rat odors did not in itself, in the absence of that odor during learning, affect discriminated escape learning, and that enhanced affinity for a contextual odor is not a sufficent condition for enhancement of learning in its presence. There was some indication that the 16‐day‐old rat was more likely to select a discriminative odor to guide their choice of spatial locations if a familiar contextual odor was present.
Techniques for observing fetal behavior in Utero: A comparison of chemomyelotomy and spinal transection
Authors: Smotherman William P. , Richards Laura S. , Robinson Scott R. 
Published: January 2005

AbstractTwo procedures–chemomyelotomy and spinal transection–have been utilized to chemically block or phsycially sever the spinal cord of pregnant rats, enabling direct observation of fetal behavior without the use of anesthesia. The effect of each procedure on fetal behavior was studied at four gestatoinal ages (Days 17, 18, 19, and 20). Substantial differneces in fetal activity were found between chemomyelotomy and spinal transection groups, including differnces in the overall level of activity as well as the pattern of developmental change of behavior. Such differntial effects indicate that chemomyelotomy and spinal transection are not equivalent maternal preparations in the study of fetal behavior.
Effects of 6‐hydroxydopamine‐induced catecholamine depletion on shock‐precipitated wall climbing of infant rat pups
Authors: Emerich Dwaine F. , Scalzo Frank M. , Enters E. Karl , Spear Norman E. , Spear Linda Patia 
Published: January 2005

AbstractSprague‐Dawley rat pups were intracisternally injected with 6‐hydroxydopamine (6OHDA) or vehicle on postnatal Day 3 and tested for footshock‐precipitated wall climbing behavior every 48 hr from postnatal Days 5 through 17. The 6OHDA treatment was observed to lower brain catecholamine levels, particularly in forebrain, and to decrease the incidence of wall climbing. This attenuation in the amount of wall climbing did not appear to be related to any neurotoxin‐induced alterations in general motor activity, body weight, or body temperature. It also did not appear that the depression in wall climbing seen in 6OHDA‐treated animals was related to an observed neurotoxin‐induced increase in shock sensitivity, given that amount of wall climbing was observed to be positively correlated with footshock intensity. These results provide further support that catecholaminergic systems are involved in the elicitation of wall climbing behavior. The 6OHDA treatment did not alter the ontogenetic time course of disappearance of this behavior pattern, suggesting that maturational changes occurring in forebrain catecholaminergic terminals may not be critical for the dissipation of wall climbing following the second postnatal week.
Control of suckling and feeding by methysergide in weaning albino rats: A determination of Y‐maze preferences
Authors: Stoloff Michael L. , Supinski Deborah M. 
Published: January 2005

AbstractTo assess the effects of serotonergic receptor blockade on the weaning process, 20‐, 25‐, and 30‐day‐old albino rat pups were injected with methysergide and were permitted to choose between suckling and feeding in a Y maze. At every age, progressively larger doses of methysergide (1) enhanced pup preferences for the suckling goal, (2) increased the frequency of suckling when in the suckling goal, and (3) decreased the frequency of feeding when in the feeding goal. These results, with the support of other findings, suggest that the weaning process may be, in part, the result of emerging or changing serotonergic neurological mechanisms.
Reproductive development in male deer mice exposed to aggressive behavior
Authors: Whitsett J. Mal , Miller Linda L. 
Published: January 2005

AbstractMale deer mice (Peromyscus maniculatus bairdii) were reared in a long photoperiod and housed individually from 3 weeks of age until they were killed 2, 4, or 6 weeks later. Males that were exposed to aggressive females for 2 min, three times per week, were of normal body weight and healthy, but had smaller reproductive organs than did males exposed to a control treatment. Reproductive development in male deer mice is responsive to at least two classes of social stimuli: pheromones and aggressive behavior.
The effects of rearing environment on pup development
Authors: Jans James E. , de Villers Sophie , Woodside Barbara 
Published: January 2005

AbstractNorway rats were reared either in a standard laboratory cage or in a nest constructed by the dam from newspaper strips. Growth, thermoregulatory ability, and adrenal, gonad, adipose tissue, and brian weights were measured at weaning on Day 21 postpartum. While there was no difference in growth, nest‐reared animals had lower body temperatures, but could thermoregulate as well as cage‐reared animals. Nest‐reared animals also had relatively smaller adrenals and less brown adipose tissue. Gonad and brain weights were similar. An interesting finding was that males and females were differentially affected by the nest‐rearing. Differences between cage‐ and nest‐reared animals were more evident in females, and thermoregulatory ability was more closely associated with the quality of the nest during the first 10 days than body weight in females. For males, body weight was more important. These latter data are discussed in relation to differential interaction between the dam and male and female pups.
Adrenalectomy in the developing rat: Does it cause reduced or increased brain myelination?
Authors: Meyer Jerrold S. , Fairman Kenneth R. 
Published: January 2005

AbstractWe have previously demonstrated increased myelination in adult rats that were adrenalectomized (ADX) neonatally. However, Preston and McMorris (1984) recently reported reduced myelination at Day 21 or 22 in day 14 ADX animals. The present experiment attempted to replicate Preston and McMorris' study to determine whether early adrenalectomy might be producing a transient hypomyelination prior to the hypermyelination observed at later time points. We were unable to duplicate the exact protocol of Preston and McMorris (which involved weaning at Day 18 with administration of saline and glucose drinking solutions) because of 100% mortality of our ADX rats by Day 20. However, using our standard mineralocorticoid replacement therapy which allowed the animals to remain with their mothers, all of the ADX rats survived, and we were able to assess myelination in these animals by means of standard biochemical methods. All measures showed absolutely no reduction in myelination in ADX rats compared with sham‐operated controls. The discrepancy between the present results and those of Preston and McMorris are attributed, at least in part, to the early weaning procedure used by these investigators.
Mediation of passive avoidance learning by nicotinic hippocampo‐entorhinal components in young rats
Authors: Blozovski Denise 
Published: January 2005

AbstractYoung rats, 11, 16, and 20 days of age, received bilateral injections of three antinicotinic agents into the posteroventral hippocampo‐subiculo‐entorhinal area, and were trained to learn a cool‐draft‐stimulus, passiveavoidance task shortly after (17 min). Gallamine triethiodide had no action at low doses and provoked convulsions at higher concentrations. Pempidine tartrate produced ageq and dose‐dependent impairments of the passive avoidance, and was much more effective in younger groups (11 and 16 days) than at 20 days. α‐bungarotoxin also induced dose‐dependent deficits. These results, together with the mecamylamine‐induced deficits already reported, suggest that nicotinic cholinergic synapses located in the posteroventral part of the hippocampal complex play a role in passive‐avoidance learning in the young rat as soon as this type of conditioning is possible, but become relatively less important at older ages, when muscarinic mechanisms also become involved.
Cochlear function and audiogenic seizures: Developmental covariance in the LP/J mouse
Authors: Henry Kenneth R. 
Published: January 2005

AbstractInnate susceptibility to audiogenic seizures develops and declines at varying rates and ages, depending upon genotype and environmental conditions. Auditory dysfunctions have been experimentally produced which induce susceptibility in otherwise nonsusceptible mouse strains. In order to more closely correlate cochlear functions and audiogenic seizures in genetically susceptible mice, both measures were obtained from LP/J mice, at ages ranging from 8 to 120 days. Susceptibility to sound‐produced convulsions was first noted at 12 days, was maximal from 18 to 32 days, declined rapidly by 40 days, and disappeared by 120 days of age. Cochlear nerve‐evoked potential thresholds were very high at 12 days, were lowest between 18 and 32 days and increased thereafter. The correlation between susceptibility and cochlear thresholds was greatest for high frequencies (r = −.93), intermediate for midfrequency (r = −.77), and poorest for low frequencies (r = −.56). It was concluded that either genetic or environmental factors which produce an intermediate level of high frequency cochlear damage in the young mouse will produce susceptibility to audiogenic seizures.