bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of early undernutrition on motivation and discrimination learning in rats
Authors: Tachibana Toshiaki 
Published: January 2005

AbstractOffspring were either adequately nourished or undernourished during the suckling period. They had free access to food from weaning, and were given 2 behavioral tests between 13 and 19 weeks of age. Motivation for water was tested on a variable interval (VI) schedule at 3 levels of deprivation and a test of light‐dark discrimination made at 23.5 hr of water deprivation. The results indicated (1) no clear difference in VI response rate, but (2) significant differences in discrimination performance between the 2 groups. A learning ability or certain relevant abilities rather than motivation for water appeared responsible for the difference in discrimination learning.
Developmental changes in open‐field behavior in the kitten
Authors: Frederickson Christopher J. , Frederickson M. H. 
Published: January 2005

AbstractSeventy‐eight kittens from 3 to 7 weeks of age were studied in an open‐field arena. Three major age‐dependent changes were noted: (1) the number of floor squares entered was markedly higher for 5‐ and 6‐week‐olds than for younger animals, and slightly lower for 7‐week‐olds than for 5‐ and 6‐week‐olds; (2) the tendency to backtrack from 1 square to a just‐vacated square decreased with age, the largest change occurring between 4 and 5 weeks of age; (3) the within‐session decrement in locomotion was largest for 3‐week‐old kittens but was smallest for 4‐week‐olds and increased monotonically with age thereafter. The results suggest a possible role of hippocampal maturation.
Paradoxical effects of d‐amphetamine upon seizure susceptibility in 2 selectively bred lines of mice
Authors: Greer Charles A. , Alpern Herbert P. 
Published: January 2005

AbstractThe ontogeny and substrates of amphetamine‐induced changes in flurothyl‐induced myoclonic and clonic seizure thresholds were investigated in 2 selectively bred lines of mice. The long‐sleep mice exhibited dose‐dependent increases in myoclonic and clonic susceptibility following amphetamine, irrespective of age. The noradrenergic agonist clonidine and the dopaminergic agonist apomorphine produced increases in susceptibility comparable to those seen with amphetamine. The short‐sleep mice, however, exhibited a dichotomous myoclonic response to amphetamine that was age‐dependent. Between 15 and 35 days of age amphetamine decreased seizure susceptibility whereas increases in susceptibility were noted at later ages. With the exception of 80 days, amphetamine did not affect clonic thresholds. In respect to myoclonus, clonidine persisted in producing effects similar to those seen in the long‐sleep mice whereas apomorphine exhibited the same ontogenetic alteration in effect seen with amphetamine. These results confirm that the short‐sleep mice might be a naturally occurring animal model of preadolescent hyperkinesis. Furthermore, the neuropharmacological tests demonstrate that the paradoxical response to amphetamine in the young short‐sleep mice is mediated via a dopaminergic mechanism that must undergo dramatic change during ontogeny.
Relationship between heart rate indices of the orienting response and birth weight in normal full‐term newborns
Authors: Stamps Leighton E. 
Published: January 2005

AbstractThe results of this study indicate that birth weight in normal term infants is related to changes in heart rate in response to auditory stimulation. Only infants above the median in birth weight responded to stimulus onset and offset. They exhibited a change in response to onset from a heart rate acceleration (defensive response) on the 1st trial to heart rate deceleration (orienting response) on later trials. The response to stimulus offset was a deceleration. Those infants below the median in birth weight showed no significant responses to onset or offset.
The effects of litter size on the expressivity of the jaundice genotype in gunn rats
Authors: Graham Dee L. , Hasenstab Laura L. , Kinney Lois , Kuntz Judith Ann 
Published: January 2005

AbstractIn 2 studies Gunn rats carrying 2 recessive alleles for jaundice (jj) were compared with their heterozygous littermates (Jj) under varied litter size (4 vs 12 pups) and handling conditions. Handling did not produce long‐term effects. Litter size interacted with Genotype to increase the differential response of jj rats by 21, 23, and 50 days of age. A decrease in survival rates and weight gain was found in Jj and especially jj rats from large litters. For jj rats only, being reared in a large litter increased the severity of ataxia. Jaundiced rats from large litters showed less rearing and tended to enter fewer squares than those from small litters whereas Jj littermates showed an equivalent amount of rearing and number of squares entered in large as compared to small litter sizes. Differences between Jj and jj rats in frequency of pivoting were greater in those from large litters than in those from small litters.
Gender differences in open‐field behavior as a function of age
Authors: Masur Jandira , Schutz Maria Teresa , Boerngen Roseli 
Published: January 2005

AbstractMale and female rats were observed in an open field at 30, 45, 60, 90, and 120 days of age. Thirty‐ and 45‐day‐old rats of both genders presented similar defecation, ambulation, and rearing scores. From 60 days on the male rats showed higher defecation scores and less ambulation and rearing than did the females. The gender difference observed in the adult rats reflected a decrease of defecation by femeles and a decrease of ambulation and rearing by males when compared to the earlier ages.
The “infantilization” of a cichlid fish
Authors: Shaw Evelyn , Innes Karen 
Published: January 2005

AbstractThis paper reports a rather remarkable phenomenon, which we have termed “infantilization.” Young acaras, 7 to 17 days postspawning age and normally freely swimming, will resume their nesting phase when placed with foster parents' brooding embryos or wrigglers. The foster parents do not eat these alien young when the young assume a behavior pattern similar to that of their own brood, namely, nest‐bound and quiescent.
Dietary and metabolic effects on rhesus social behavior: Protein and protein‐calorie malnutrition
Authors: Chamove A. S. 
Published: January 2005

AbstractForty‐seven monkeys were fed 1 of 8 diets between the ages of 1 and 7 months containing full‐, half‐, or quarter‐strength protein or protein and calories using either casein or soy protein. While on the diet, malnourished infants were inactive both socially and nonsocially. When returned to a normal diet, previously malnourished subjects were more agonistic towards familiar peers but more friendly and less agonistic when paired with unfamiliar monkeys. The data suggest that short periods of early severe malnutrition may protect the individual against adverse social conditions (e.g., isolation) and delay the development of normal social skills.
The ontogenesis of sleep states, thermogenesis, and thermoregulation in the virginia opossum
Authors: Walker James M. , Berger Ralph J. 
Published: January 2005

AbstractPolygraphic recordings of sleep and wakefulness were obtained over 4‐hr periods from infant opossums, aged 48–79 days, while they were in the mothers' pouches. Concurrent body temperature measurements were obtained from littermates held at ambient temperatures of 25 and 30°C. The ontogenesis of sleep was similar to that of placental mammals: quiet sleep increased from 13% sleep time at 48 days to 55% at 79 days; conversely, active sleep decreased from 87% to 45%, respectively. The amplitude of the electroencephalogram (EEG) during quiet sleep increased with age and quiet sleep could be categorized as slow wave sleep at 75 days. Active sleep could be identified as rapid eye movement sleep at the same age. Temperature measurements revealed that thermogenesis appeared at approximately 55 days and the 1st signs of thermoregulation were apparent at 67 days. Near‐adult thermoregulatory capabilities were present by 79 days. Increases in percent time spent in quiet sleep corresponded with increases in percent adult thermogenesis. The appearance of slow wave EEG activity coincided with the onset of thermoregulatory capabilities. We suggest that lowered metabolism associated with slow wave sleep is adaptive in offsetting the increased energy demands of thermogenesis.
Ontogeny of behavioral sensitivity to glycine in the chick embryo
Authors: Reitzel J. , Oppenheim R. W. 
Published: January 2005

AbstractStrychnine (STR), glycine (GLY), and γ‐aminobutyric acid (GABA) were injected intravenously into 6‐ and 7‐day chick embryos and subsequent effects upon spontaneous motility were observed. In 7‐day embryos STR alone increased motility and when injected simultaneously with GLY antagonized the GLY‐induced motility decrements; STR did not antagonize GABA‐induced motility decrements. In 6‐day embryos STR injected alone had no effect on motility, but did antagonize motility decrements induced by the simultaneous injection of GLY; again STR did not antagonize GABA‐induced motility decrements.
Retention under changed‐reward conditions of persistence learned by infant rats
Authors: Chen Jaw‐Sy , Amsel Abram 
Published: January 2005

AbstractTwo experiments were performed to determine whether or not persistence acquired under reinforcement conditions of infancy can be retained and transferred to adult reinforcing conditions. In Experiment I 2 groups of rats 14–15 days of age were trained in a runway under a partial (PRF) or continuous (CRF) schedule of milk‐suckling reinforcement. A 3rd group was trained under continuous nonreinforcement (NRF) conditions. The PRF and CRF groups acquired the approach response about equally, and the NRF showed a very small increase in speed. In immediate extinction, the PRF group was more resistant to extinction than its CRF counterpart. For the NRF group “extinction” produced a continuation of the low‐level “acquisition” performance. Experiment II showed that persistence acquired at 14–15 days with milk‐suckling reinforcement can be sustained through a 2‐week retention period including a phase of CRF food‐pellet reward.
Passive avoidance learning in the young rat
Authors: Blozovski Denise , Cudennec Annie 
Published: January 2005

AbstractA step‐through locomotor passive avoidance task is described requiring the suppression of a spontaneous escape reaction from a cool toward a warm compartment in order to avoid an electric shock delivered in the warm side. We observed no learning of this task at 9 days of age, a very low but significant level of acquisition at 11 days, a slow but progressive improvement of avoidance from the 13th until the 17th day when the adult capacity was achieved, and a marked increase in the rate between 17–20 days.
Periodicity in the behavior of grain beetle larvae
Authors: Sheimann I. M. , Khutzian S. S. , Ignatovitch G. S. 
Published: January 2005

AbstractLarvae of the grain beetle (Tenebrio molitor) were trained in a T‐maze at different stages of the same instar. The larvae's aptitude for learning changed depending on the stage of their development: poor in the middle of the intermoulting period, but much improved upon approaching the next moult and during the 1st day thereafter. Such regularity seems to be related to general laws of cyclic development of the insect larvae as governed by the hormones of metamorphosis.
Avoidance learning under delayed shock termination in prenatally x‐irradiated rats
Authors: Tamaki Yoshitaka , Inouye Minoru 
Published: January 2005

AbstractGroups of MP1 male albino rats were exposed to x‐irradiation of 200 rad on Day 17 of gestation. Irradiated and control rats were trained in a shuttlebox with either immediate or .5‐sec delayed termination of both the electric shock (US) and the conditioned stimulus (CS) on escape trials. An avoidance response always produced prompt CS termination. Irradiated rats showed a higher degree of avoidance behavior than controls and, under the delay condition, tended to run rapidly in the CS‐US interval.
Perinatal methylmercury intoxication: Behavioral effects in rats
Authors: Schalock R. L. , Brown W. J. , Kark R. A. P. , Menon N. K. 
Published: January 2005

AbstractSprague‐Dawley rats were subjected to perinatal (4th gestational day until Postnatal Day 21) methylmercury intoxication to determine the long‐term behavioral effect of the mercury poisoning. Experimental and control animals were evaluated at 110–140 days of age. Compared to controls, the methylmercury animals demonstrated significant behavioral deficits characterized by hypoactivity and by reduced appetitive, escape, and avoidance learning.
Development of wing‐flapping and flight in normal and flap‐deprived domestic chicks
Authors: Provine Robert R. 
Published: January 2005

AbstractLateral flight evoked by dropping appeared 7–9 days after hatching. Drop‐evoked bilaterally symmetrical wing extension and slow, low‐amplitude wing‐flapping were present by Day 1. Flapping rate measured using strobophotography increased up to approximately 13 days. Normal wing‐flapping rates and lateral flight distances were achieved by chicks whose wings were immobilized with elastic bandages from Day 1 until immediately before testing at 13 days, indicating that wing movement is not necessary for the postnatal development of basic wing‐flapping and flight. The ratio of wing area to body weight, a morphological index of wing‐lift efficiency, rapidly increased up to 13 days and slowly declined through 49 days. The peaking of this ratio at 13 days corresponds to the age at which lateral flight is well established and wing‐flapping rate is its maximum. Thus, the development of wing morphology, wing‐flapping rate, and flight are strongly and positively correlated.
The effect of early visual experience on spatial maze learning in rats
Authors: Tees Richard C. , Midgley Glenda , Nesbit John C. 
Published: January 2005

AbstractIn the 1st of 2 experiments on spatial ability, groups of sighted and blind, light‐reared (LR) and dark‐reared (DR) rats were tested on a series of (Hebb‐Williams) maze problems and their reversals under appetitive and aversive reinforcement conditions. Significant effects due to early rearing conditions, vision at time of testing, and problem were found. Dark‐reared rats learned the problems whose solution depended on nonvisual cues more slowly than LR animals. Blindness at time of testing had a significantly adverse effect on the performance of LR and DR rats on all problems, but a significantly greater effect in the DR animals. In a 2nd experiment DR rats were also found to perform less effectively than LR rats on a 17‐arm radial maze throughout a 36‐day period during which variations in the task were introduced. The results reveal the impact of early visual experience on the development of the ability to acquire spatial concepts.
Age and brightness discrimination learning by C57BL/6J mice
Authors: Warpen J. M. 
Published: January 2005

AbstractGroups of 20–34 C577BL/6J mice, aged 75, 225, 375, and 525 days, learned a brightness discrimination for water. The error scores of the 75‐ and 525‐day groups were almost identical, and both made significantly more errors than the 225‐day‐old mice. Both immature and older mice appear to be deficient in learning ability compared to young adults.
Olfactory development in gerbil pups
Authors: Cornwell‐Jones Catherine A. , Azar Leila M. 
Published: January 2005

AbstractIn a 2‐choice situation, Mongolian gerbil pups show a preference for home‐cage bedding odor that appears during the 2nd postnatal week and is consistently high between Days 8 and 14. Pups show responses to certain nonanimal odors as early as Day 4, indicating that the motor capacity to orient to odors precedes the emergence of nest odor preference. Increases in pups' nest odor preference appear to parallel increases in the frequency of maternal nest‐building, an activity which can eject pups from the nest. This coincidence suggests that olfaction helps displaced pups to return to their nests.
Cortical depth changes in enriched and isolated mice
Authors: Cummins R. A. , Livesey P. J. , Bell J. A. 
Published: January 2005

AbstractThe occipital cortical depth was determined in laboratory mice at both 14 and 20 days of age and after various periods of postweaning exposure to enrichment or isolation. The depth was found to be maximal at 20 days of age. It declined thereafter, irrespective of environment, but the isolate cortical depth decreased faster than the enriched. The postweaning depth of the occipital cortex appears to be determined by an inevitable age‐related decrease whose rate of decline may be attenuated by sensory stimulation. The postweaning cortical depth may reflect the extent of cortical neuronal development and associated metabolic activity.
Intense rapid eye movements during active sleep: An index of neurobehavioral instability
Authors: Becker Patricia T. , Thoman Evelyn B. 
Published: January 2005

AbstractRapid Eye Movement (REM) Storms, intense REM bursts during Active Sleep (or REM Sleep), were investigated as an expression of the neural mechanisms involved in overall control of the sleep and waking states. Twenty normal full‐term infants were observed in their homes for a 7‐hr period when they were 2, 3, 4, and 5 weeks old. Sleep and waking states, and co‐occurring behaviors of the mother, were recorded at 10‐sec intervals throughout the observation day. During each 10‐sec epoch of Active Sleep a rating was made of the infant's rapid eye movements, as follows: No REM, Light REMs, Moderate REMs, or intense REMs (REM Storms).REM Storm rates were related to a measure of stability in the distribution of the sleep and wake states over weeks, derived separately for time the infant was alone and for time the infant was with its mother. REM Storm rates were negatively correlated with state stability in each of these contexts. The results demonstrated a commonality between the incidence of REM Storms and overall sleep‐wake state regulation.
Studies of social learning in norway rats: A brief review
Authors: Galef Bennett G. 
Published: January 2005

AbstractI review below some of the research on social learning in Norway rats carried out in my laboratory from 1969 to 1980. Two independent lines of research are discussed; both involve analysis in the laboratory of possible instances of social learning first described by observers of free‐living, wild rats. The 1st research program analyzes social interactions important in the transmission of learned food preferences from adult rats to their young. The 2nd examines the possibility that the habit of diving in shallow water for food is socially transmitted from 1 rat to another.
Sexual imprinting in male japanese quail: The effects of castration at hatching
Authors: Hutchison R. E. , Bateson Patrick 
Published: January 2005

AbstractThis study investigated whether gonadal hormones are required for sexual imprinting in male Japanese quail during the period of exposure to the imprinting stimulus. Brown males were either castrated or laparotomized on the day of hatching. Between Days 10 and 30 of age castrated males (N = 15) and intact laparotomized males (N = 10) were exposed individually to white females. A 2nd group of intact laparotomized males (N = 13) were exposed to brown females. When adult (Day 54), 7 of the castrated males were treated with testosterone propionate (TP): the remaining 8 castrated males and intact groups received saline. All males were given choices between novel white and novel brown females starting on Day 62. The TP‐treated castrated males behaved like intact white‐exposed males, preferring to approach and copulate with white females significantly more readily than did intact brown‐exposed males. The untreated castrated males showed no sexual behavior. The results indicate that gonadal hormones are not required during the period of exposure to an imprinting stimulus in male Japanese quail.
Reproductive functioning in the prenatally stressed female rat
Authors: Beckhardt Stacey , Ward Ingeborg L. 
Published: January 2005

AbstractThe reproductive behavior and physiology of female offspring of rats stressed during pregnancy were assessed. Mothers were restrained and placed under bright, hot lights from Day 14 through 21 of gestation. This treatment, which is known to disrupt the sexual behavior of male offspring, did not alter reproductive functioning in the female offspring. The females showed evidence of normal cyclicity, sexual behavior, pregnancy, parturition, pup survival, and maternal behavior when tested beginning at 70 or at 140 days of age.
The effects of early rearing environments on maternal behavior in adult female rats
Authors: Moretto Denise , Paclik Lida , Fleming Alison 
Published: January 2005

AbstractThe purpose of this study was to determine the effect of presence of siblings and exposure to colony cues during early life on the onset of maternal behavior at 20 and 75 days of life, and on subsequent emotional behavior in juvenile and adult female rats. Different groups of animals were reared either (1) with a large number or a small number of siblings (sibling factor), or (2) in the colony room or in a room apart from other mothers with pups (colony factor). Animals were tested for latency (in days) to show maternal behavior at either 20 or 75 days of age, and for emotional behavior (using the open field apparatus) at either 20–40 or 80–100 days of age. Exposure to colony sensory cues significantly reduced latencies for pup retrieval and nestbuilding in adults, but not in juveniles. Exposure to a large number of siblings reduced the latencies, in both adults and juveniles, to nest build; in juveniles, to lie over 75% of the litter; and in adults, to adopt a nursing posture. Consistent with prior research, juveniles had longer latencies than adults for a number of pup‐directed behaviors including: latency to become maternal, latency to retrieve pups, latency to adopt a lactating posture, latency to lick/genital lick, and latency to nest‐build. In the emotionality tests, the young animals scored as less emotional than the adults, an effect which was further exaggerated by early colony exposure. Overall results indicated that manipulation of early rearing environments does have a significant positive effect on later responses to young pups by both juvenile and adult female rats.
Ontogenetic change in the analysis of sound frequency in the infant rat
Authors: Hyson Richard L. , Rudy Jerry W. 
Published: January 2005

AbstractPrevious research has shown that there is an ontogenetic shift in the spatial code of sound frequency in the cochlea and central auditory nuclei. During ontogenesis, a given area of the basilar membrane or central auditory nuclei is maximally stimulated by sounds of progressively higher frequencies. Here, a similar ontogenetic shift in the rat's “perception” of sound frequency is reported. Animals were trained with a tone (CS) paired with footshock (US) and generalization of their conditioned response (CR) to different frequencies was assessed either 0.5 or 72 hr later. When 15‐day‐old animals were trained with an 8‐kHz tone and tested 0.5 hr later, greater suppression of activity (CR) was evoked by the 8‐kHz tone than by either a 12‐kHz or a 6‐kHz tone. When tested 72 hr after training, however, greater suppression of activity was evoked by a 12‐kHz tone than by the 8‐kHz training stimulus or by a 24‐kHz tone. This shift in the peak of the generalization gradient could not be accounted for by changes in unconditioned responses to the test stimuli. Additionally, the observed shift in the generalization gradient was age‐dependent. It was not observed when pups were trained at 18 days old and tested 72 hr later. The implications of these data for studies of the ontogenesis of learning and memory are discussed.