bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of home orientation in hypothyroid and hyperthyroid rat pups
Authors: Johanson Ingrid B. , Turkewitz Gerald , Hamburgh Max 
Published: January 2005

AbstractIn order to assess the effects of perinatal hypothyroidism or hyperthyroidism on the development of an integrated behavioral response, we tested hypothyroid, hyperthyroid, and control pups, as well as pups receiving thyroxine replacement therapy, for the development of the home orientation response. Hypothyroidism was induced in the pups by feeding the pregnant or lactating female a diet of .2% propylthiouracil from Day 15 of gestation to Day 22 postpartum. Pups receiving replacement therapy and pups made hyperthyroid were injected daily with thyroxine, starting at birth. The ability of the pups to initiate and maintain locomotion toward the nest was assessed between Days 4 and 22. Hyperthyroid, control, and replacement therapy pups behaved very similarly on the task, showing a peak in the percentage of pups homing between Days 12 and 16. Hypothyroid pups showed a delay in the peak percentage until Day 20, although the percentage of pups was similar to that found in other treatments. An integrated behavioral response can be delayed by hypothyroidism and still emerge apparently intact at a later age.
Development of olfactory and thermal responsiveness in hypothyroid and hyperthyroid rat pups
Authors: Johanson Ingrid B. 
Published: January 2005

AbstractHypo‐ and hyperthyroid rat pups were tested for their responsiveness on an olfactory and a thermal gradient in an attempt to evaluate the effects of perinatal thyroid manipulation on the ability of the pups to use these cues in orientation. Hypothyroid pups showed a delay and hyperthyroid pups an acceleration in the development of orientation along the olfactory gradient, relative to controls. None of the pups was able to utilize a thermal gradient in directed orientation but pups moved less at the warm end of the gradient than at the cool end. This differential responsiveness was strongest in the hypothyroid pups, suggesting that these pups could utilize thermal cues in an orthokinetic orientation.
Ontogeny of short‐ and long‐term memory capacities for passive avoidance training in undernourished mice
Authors: Nagy Z. Michael , Porada Kenneth J. , Monsour Ann P. 
Published: January 2005

AbstractTo assess the effects of early postnatal undernutrition upon the developing abilities of infant and juvenile mice to acquire and retain a passive‐avoidance response, we reared mice following birth in either “normally nourished” or “undernourished” conditions by maintaining litter sizes of 6 or 16, respectively. At ages ranging from 7 to 21 days of age, mice from each nutritional condition were trained to withhold stepping off from a small vibrating platform in order to avoid shock. Following training to a common criterion, separate groups of mice were retrained to the same criterion either 1 or 24 hr later. From the comparisons with yoked control groups at each age and retention interval, we conclude that although undernutrition results in some age‐related differences in the ability to withhold responding, these are quite small during acquisition within each age group. In contrast, the retention data suggest that undernutrition delayed the development of both short‐ and long‐term memory abilities on this task. In general, these results are similar to earlier data involving discriminated shock‐escape wherein undernutrition had little apparent effect upon acquisition at the early ages but rather marked effects upon developing memory systems.
Relative effects of maternal and pup heredity on postnatal mouse development
Authors: Wainwright Patricia 
Published: January 2005

AbstractThis study was designed to assess the separate effects of inbreeding the mother and the pups on behavioral development in the mouse. The pups were tested on a standardized developmental rating scale at 32 days gestational age. The results indicated that maternal inbreeding retarded development by 1.5 days and that inbreeding the pups retarded development by .7 days.
Interactive effects of nutrition and cannabis upon rat perinatal development
Authors: Charlebois A. T. , Fried P. A. 
Published: January 2005

AbstractIn order to examine the effects of cannabinoids, malnutrition, and their possible interaction upon the developing rat fetus, female Wistar rats were exposed to cannabis smoke, placebo smoke, or no smoke while concurrently consuming 1 of 3 diets differing in protein concentration (8%, 24%, 64%). Both the diet and drug treatments were administered 20 days prior to and throughout gestation. Of the 12 variables affected by the low‐protein diet, 8 were significantly potentiated when undernutrition was combined with cannabis treatment. Some dependent variables that were not altered either by the low‐protein diet or by cannabis inhalation were affected by the combination of treatments. These included a lengthened gestation period, an increase in occurrence of stillbirths and litter destruction, and decreased activity in the rat pups. Cannabis coupled with a standard protein diet resulted in a number of developmental indices being delayed but combining the drug with an enriched protein diet ameliorated these effects. The evidence also suggests that the administration of cannabis both before and during gestation resulted in a degree of tolerance to some aspects of the drug effects.
Circumcision, gender differences, and neonatal behavior: An update
Authors: Brackbill Yvonne , Schroder Kerri 
Published: January 2005

AbstractAs a test of the hypothesis that gender differences in neonatal behavior may be linked to circumcision, we reviewed 38 recent studies which provide relevant information. No strong data exist to support the hypothesis or to document the existence of gender differences in neonatal behavior.
Learning deficits in the neonatal peking duckling produced by decreased oxygen consumption during late prenatal periods: A cautionary note
Authors: Heaton Marieta B. , Klein Steven L. 
Published: January 2005

AbstractNeonatal Peking ducklings were tested in a detour problem‐solving task following replacement of the shell overlying the air space of the egg on Prenatal Day 24 (total incubation period: 27 days) with a plastic wrap. This procedure, a common practice in behavioral embryology, resulted in a significant decrease in oxygen consumption, and a protracted retardation in the mastery of the learning task, with experimental ducklings solving the problem at a mean age of 5.27 days, compared with 2.32 days for controls. These results serve to underscore the problems that may be encountered as a result of any intereference with the integrity of the egg during the prenatal period.
Recovery from experimentally induced problem‐solving deficits in neonatal peking ducklings as a function of environmental stimulation
Authors: Heaton Marieta B. , Klein Steven L. 
Published: January 2005

AbstractNeonatal Peking ducklings were reared in 3 different environments containing varied light and sound stimulation. One group was exposed to the stimulative environment only during the last 3 prenatal days, 1 group was placed in the stimulative environment at the time of hatching, and the 3rd group was exposed to the stimulative environment both pre‐ and postnatally. No differences in performance in a detour learning task were noted between controls and experimentals from the 1st 2 groups (prenatal stimulation only and postnatal stimulation only); however, the group receiving both pre‐ and postnatal stimulation solved the detour task significantly faster than their controls. This learning improvement as a function of the stimulative environment represents a partial recovery from the deficit produced as a result of the experimental paradigm in which the shell covering the air space was replaced with clear plastic wrap, a procedure which has been shown to reduce oxygen consumption and lead to learning retardation.
Suckling: Developmental indicator of genetic obesity in mice
Authors: Wilson Linda M. , Chang Shih‐Shung P. , Henning Susan J. , Margules David L. 
Published: January 2005

AbstractThe Bar Harbor obese‐hyperglycemic mouse (ob/ob) characteristically develops its obese phenotype during the postweaning period, when access to food is unrestricted and its behavioral phenotype of hyperphagia appears. In the present study suckling behavior (viz., nipple attachment latencies and total suckling time) of lean and preobese mouse pups, derived from matings of heterozygous lean parents, was measured in either fed or fasted conditions from 6 to 21 days postpartum on anesthetized dams. Twenty‐hour milk deprivation selectively channeled pup activity into suckling for both preobese and lean mice, although, in general, preobese mice nipple‐attached sooner and suckled longer than leans. In particular, fed preobese pups suckled longer than fed lean pups from 18 days on, providing a preweaning behavioral indicant of a genetic tendency to obesity when environmental constraints on overeating are minimized.
Heightened arousal in the 2‐week‐old rat: The importance of starvation
Authors: Moorcroft William H. 
Published: January 2005

AbstractThe 2‐week‐old rat has frequently been reported to be hyperactive; however, the causes of this are disputed. In 3 experiments, with split‐litter designs, the following possibilities were eliminated as causative factors: (a) body temperature; (b) nest seeking; and (c) maturation of peripheral sensory, motor, and endocrine systems. In contrast, the isolated 2‐week‐old rat, in a novel environment, was shown to be very reactive to hunger, however mild. Further, this was true whether the hunger was self‐generated during a forced switch in diet or of external origin due to food deprivation. These data are consistent with and supportive of the hypothesis that the 2‐week‐old rat does not have functionally‐mature forebrain inhibitory structures with which to modulate arousal. Thus, even a mild arousal stimulus results in extreme hyperactivity. Further, these results, together with previously published results, suggest that the concurrence of isolation, starvation, and novelty of environment are necessary, but none of these alone is sufficient, for the 2‐week‐old rat to become hyperactive.
Deficits in spatial memory performance induced by early undernutrition
Authors: Jordan T. C. , Cane S. E. , Howells K. F. 
Published: January 2005

AbstractRecent studies have shown that rats have a remarkable ability to keep track of their spatial location. Explanations stress the involvement of a form of short‐term (working) memory in which the hippocampus appears to play a major role. The hippocampus appears to be vulnerable to early undernutrition and preliminary investigations indicate that Areas CA3 and CA4 suffer the most. Ninety‐day‐old rats, previously undernourished prenatally and throughout lactation, were tested in an 8‐ and, then, a 16‐arm radial maze. Significant differences were observed between the experimental and control groups on both tests, especially in the 16‐arm maze. Error distributions were also significantly different with experimental animals tending to perseverate in 1 area of the maze. Differences were also observed in the time taken to make the choices and in exploratory behavior. We conclude that early undernutrition affected the spatial learning ability of the animals and that this may be due to the distortions observed in the normal growth pattern of the hippocampus.
Isolation has permanent effects upon the behavior of the rat, but not the mouse, gerbil, or guinea pig
Authors: Einon Dorothy F. , Humphreys Anne P. , Chivers Susan M. , Field Sarah , Naylor Vivian 
Published: January 2005

AbstractIn the rat isolation has both short‐and long‐term influences upon behavior. Rats isolated at any age will show increases in timidity and aggression, but both effects can be reversed by periods of social housing. However, isolation before 50 days of age has permanent effects upon behavior. We have previously found that rats between 25 and 45 days of age may be protected from the deleterious effects of isolation by short daily periods of social contact if, during these daily contact periods, the rats engage in intense bouts of rough‐and‐tumble play. In this study we examined the permanence of the effects of isolation on the rat, mouse, guinea pig and gerbil. As predicted by the play hypothesis, species which do not engage in extensive social play do not show permanent deficits if isolated prior to 50 days. Only rats which engage in long bouts of rough‐and‐tumble play between 20 and 50 days show any permanent behavioral effects of isolation during this period.
Hypothermia‐induced retrograde amnesia in mature and aged rats
Authors: Hamm Robert J. 
Published: January 2005

AbstractMature (10‐month‐old) and aged (25‐month‐old) rats were trained on a passive avoidance task. Following training, rats in each age group were exposed to a hypothermia treatment, restraint alone, or no treatment. The hypothermia treatment involved immersing the mature rats in 4°C water for 12 min and immersing the aged rats in 1°C water for 12 min. This treatment reduced the body temperature of both age groups to an equivalent temperature (22°C). Following immersion, the body temperature of the aged rats continued to decline to a lower level and recovered at a slower rate than the mature rat's temperatures. When all rats were tested 24 hr after training for retention of the avoidance task, mature rats performed better than aged rats when trained with the same shock intensity. Increasing the shock duration for the aged rats eliminated the performance differences on the passive avoidance task between ages. Rats exposed to hypothermia showed poorer retention of the task (i.e., retrograde amnesia) than all control conditions. However, no age differences in the degree of amnesia induced by the hypothermia treatment were apparent once age groups were equated on the intensity of the amnesic agent (hypothermia) and degree of initial learning.
Effects of handling during infancy on the sympathetic–adrenal medullary system of rats
Authors: McCarty Richard , Horbaly William G. , Brown Maire S. , Baucom Katheryn 
Published: January 2005

AbstractWe examined the effects of daily handling and maternal separation (5 min per day) on the responsiveness of the sympathetic‐adrenal medullary system of Sprague‐Dawley rats before weaning and in adulthood. Plasma levels of norepinephrine (derived primarily from sympathetic nerves) and epinephrine (released from the adrenal medulla) were elevated in handled pups compared to unhandled controls at 14 and 18 days of age but not at 6 and 10 days of age. When tested in adulthood, previously handled and control rats did not differ with respect to basal or stress‐induced increments in plasma levels of norepinephrine and epinephrine. These results indicate that brief daily episodes of handling and maternal separation are attended by an increase in sympathetic‐adrenal medullary tone in 14–18‐day‐old rats. However, the enhanced response of the sympathetic–adrenal medullary system of separated rats may not persist into adulthood.
Effects of fostering on seizure activity in the Mongolian gerbil
Authors: Kaplan Harriett 
Published: January 2005

AbstractThe purpose of this experiment was to ascertain whether seizure propensity in Mongolian gerbils is affected by differences in behavior and/or nurturing ability of seizure‐prone (SP) and nonseizure‐prone (NSP) parents. Day‐old SP and NSP pups were cross‐fostered, while other SP pups were fostered to SP parents. Matched nonfostered littermates served as controls. The SP gerbils fostered to NSP parents exhibited delayed onset of seizure activity whereas SP gerbils fostered to SP parents did not. Neither fostered nor nonfostered NSP gerbils ever underwent seizures. This experiment establishes that some familial defect underlies seizure‐proneness in gerbils, but that expression of this tendency is affected by parental behavior and/or nurturing ability.
Persistence of attention to a novel conspecific: Some developmental variables in laboratory rats
Authors: Thor D. H. , Wainwright K. L. , Holloway W. R. 
Published: January 2005

AbstractPersistence of social attention by male and female laboratory rats was examined following exposure to novel conspecifics. In Experiment I we compared performance of castrate females treated with a 10‐day regimen of testosterone propionate to that of intact males and castrate female controls. Testosterone significantly prolonged mean social investigation time. Castrate females treated with a relatively high dosage of testosterone failed to differ from intact males. In Experiment II we compared neonatally andorganized female castrates with castrate male and castrate female controls. Postnatal exposure to testosterone increased sensitivity of females to exogenous testosterone in maturity as measured by persistence of social investigation. In Experiment III we compared investigation time of intact and castrated males and females at 10‐day intervals from 40 to 80 days of age. Intact males investigated novel conspecifics significantly longer than other groups, with longest investigation times at 60 and 70 days of age. In Experiment IV we compared investigation times of 30‐day, 60‐day, and 200‐day‐old males. Sixty‐day‐old males investigated significantly longer than 30‐day‐old or 200‐day‐old groups, which failed to differ from each other. The combined results demonstrate a gender and aggregated effect of testosterone on persistence of social investigation.
Effects of environmental enrichment on old mice
Authors: Warren J. M. , Zerweck C. , Anthony A. 
Published: January 2005

AbstractFifteen male C57BL/6J mice, exposed to an enriched environment from age 600 to 750 days, were compared with 15 matched controls on 4 learning problems and an activity test. The enriched mice were significantly superior on an incidental learning and a food‐seeking task, but did not differ significantly from controls on a brightness discrimination task, the Lashley III maze and an activity test. The relative abundance of high and low ribonucleic acid‐containing cerebrocortical cells differed significantly between groups; the enriched mice had more cells with very high levels of RNA. The mammalian brain appears to remain responsive to environmental enrichment well into advanced age.
Early stress effects on growth and adult behavior in Poecilia reticulata
Authors: Newton Barbara J. 
Published: January 2005

AbstractSmall mammals subjected to early stress show decreased aggression and emotionality, accelerated rates of maturation, and increased sexual activity, affiliation, and size. The purpose of this experiment was to test the phyletic generality of this phenomenon using fish (Poecilia reticulata) and, also, to control for the sensitivity of the measures, to determine if controls for both water quality and rearing‐testing conditions might produce different effects than have previously been reported for fish, and to see in what respects the effects of isolation and crowding are similar to those generally found in mammals. Early‐stressed guppies showed reduced aggression, but did not differ from controls on any other measure. Isolated and crowded guppies differed from each other and from the controls on 4 of the 6 measures. Isolated fish matured more rapidly and attained greater adult length than did the controls; the reverse was true for crowded fish. Crowded fish showed higher levels of emotionality than controls, whereas isolates showed lower levels than controls. No differences were noted in affiliation, although crowded fish spent more time in the vicinity of empty stimulus boxes. Crowded fish did not differ from controls in levels of sexual activity or display, but isolated fish showed low levels of sexual activity and high levels of display. These findings suggest that at least part of the early stress phenomenon shown in small mammals may be demonstrated in fish.
The contribution of ambient temperature to suckling behavior in rats 3–20 days of age
Authors: Cramer Catherine P. , Blass Elliott M. 
Published: January 2005

AbstractTo assess the role of ambient temperature on the expression of adultlike control over suckling behavior of infant rats, preweanling pups were tested for nipple attachment and milk intake while suckling in either room temperature (25°C) or nest temperature (34°C). In one experiment, attachment latency was measured following 0, 4, or 24 hr of deprivation at 3, 6, 9, 12, or 15 days of age. Latency was generally reduced by testing in high ambient temperature. Increasing deprivation reduced latency at all ages. Elevated temperature, however, did not accentuate deprivation‐dependent differences. In a 2nd experiment, milk intake via a posterior tongue cannula was measured in pups 5, 10, 15, or 20 days of age, suckling at either room or nest temperature. Environmental temperature did not significantly affect intake at any age. These data eliminate ambient temperature as a critical factor for adultlike control of suckling behavior in infant rats.
Delay and acceleration of puberty in female mice by urinary chemosignals from other females
Authors: Drickamer Lee C. 
Published: January 2005

AbstractA sequence of 7 experiments tested various aspects of the acceleration and delay of sexual maturation in young female mice as affected by cues from other females: Singly caged females produce the maturation‐delaying chemosignal when exposed to urine from grouped females. Urine from females housed 3 or more/cage produces delays in puberty for young females. Urine from females in estrus accelerates puberty in young females relative to untreated controls or urine from nonestrous females. The delay‐of‐maturation phenomenon in female mice is not affected by reproductive history, cross‐fostering of pups, or varying the cagemates according to whether they are sibs or nonsibs. Taken together these and previous findings suggest that female mice excrete, in their urine, a series of chemicals which act as signals regarding the adequacy of reproductive conditions.
The development of proxemic spacing behavior: Children's distances to surrounding playmates and adults change between 6 months and 5 years of age
Authors: Wesley Burgess J. , McMurphy Denice 
Published: January 2005

AbstractThe patterns of distances maintained between 30 children and 15 adult caretakers were measured to determine developmental trends in children's patterns of interpersonal spacing toward adults and playmates. Children's positions during free play were photographed at 60‐sec intervals and analyzed with a computer to determine the mean distances children maintained toward their 1st through 5th nearest adult caretakers and toward their 1st through 5th nearst playmates. Children's distances from adults increased with age, while distances from playmates and spatial variability decreased with age. Only infants (6–18 months) stayed significantly close to any of their adult caretakers; toddlers (19–27 months) and preschoolers (30–60 months) avoided proximity to their 3rd through 5th nearest adult caretakers more than could be expected by chance. All age groups significantly avoided proximity to their 4th and 5th nearest playmates; avoidance of playmates' space decreased with age.