bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellular distribution of the mRNA for the α7 subunit of the nicotinic acetylcholine receptor in the human cerebral cortex
Authors: Wevers A. , Sullivan J. P. , Giordano T. , Birtsch Ch. , Monteggia L. M. , Nowacki S. , Arneric S. , Schröder H.
Published: January 2005

Central nicotinic acetylcholine receptors (nAChRs) are ligand‐gated cationic channels characterized by a wide pharmacological and molecular diversity depending on the subunits involved. Recently a new type of a nicotinic acetylcholine receptor channel, highly permeable to calcium, consisting of α7 subunits which bear a binding site for the snake venom α‐bungarotoxin has been described. α‐bungarotoxin binding sites have previously been localized in the human and rat brain. Immunohistochemistry has revealed the presence of α7 subunits in the rodent CNS. Presently we have applied digoxigenin‐labeled RNA probes to localize α7 mRNA in human brain using autopsy samples of prefrontal (Area 10) and motor cortex (Area 4). α7 transcripts are expressed in numerous neurons throughout both cortical regions. Mainly pyramidal‐like neurons of layers II/III, V, and VI were labeled. In contrast to our previous studies on the localization of α3 and α4 transcripts, only a few giant pyramidal neurons in A4 but a rather high number of layer I neurons in A4 and A10 expressed α7 mRNA. The study shows that nicotinic receptor subunit mRNAs are distributed in a subunit‐ and area‐specific manner in the human cerebral cortex. These findings will be of importance as to the selective, ligand‐mediated stimulation of nicotinic receptor subtypes as a possible tool to improve cholinergic transmission in neurodegenerative disorders like Alzheimer's disease. © 1995 Wiley‐Liss, Inc.
Evaluation of the dependence liability of quinolizinones acting as partial agonists at the benzodiazepine receptor
Authors: Martin James R. , Moreau Jean‐Luc , Jenck François
Published: January 2005

The quinolizinones Ro 19‐5663, Ro 19‐5686 and Ro 41‐3696 bind with high affinity to the benzodiazepine receptor (BZR) in vitro in the rat brain. These compounds exhibit anxiolytic‐like effects in an operant punishment task in mice and rats and anticonvulsant effects by fully protecting against pentylenetetrazol‐induced tonic seizures in mice and rats and fully protecting against audiogenic seizures in genetically susceptible mice. However, they produced at most only minimal motor impairment in the rotarod task in rodents. These compounds attenuated flunitrazepaminduced sleep in squirrel monkeys, thus antagonizing the effects of a BZR full agonist. In a precipitated withdrawal paradigm, chronic oral treatment in seizure‐prone young DBA/2J mice or adult squirrel monkeys was followed by iv challenge with the BZR antagonist sarmazenil. Following the completion of a chronic treatment regiment with high doses of these quinolizinones, no signs of precipitated withdrawal were observed in mice and only weak signs of sarmazenil‐induced withdrawal were observed in monkeys. In contrast, sarmazenil challenge after chronic treatment with the BZR full agonists triazolam and alprazolam elicited marked withdrawal reactions in mice and monkeys, respectively. In sum, these quinolizinones are BZR partial agonists which offer potential anxiolytic and anticonvulsant efficacy concomitant to reduced adverse effects, including a clear reduction of dependence liability, in comparison to BZR full agonists. © 1995 Wiley‐Liss, Inc.
Development of membrane potentials of cortical cell elements in guinea pig fetus
Authors: Sedláček Jndřich
Published: January 2005

The mean membrane potentials of cellular elements were measured during the passage of a glass microelectrode through cortical tissue in fetuses and newborn guinea pigs. The average value of membrane potential increases in fetuses after the 47th day of gestation from 7.6 mV to 28.1 mV in newborn guinea pigs. The developmental changes in histograms of individual values correspond to the increase in mean value. The membrane potentials are sensitive to brain hypoxia following cord clamping only after the 62nd day of gestation. In term fetuses, cord clamping is followed by regular lung ventilation and by the slow gradual increase of mean value in membrane potentials. The development of the mean membrane potential of cortical elements correlates well with the development of the cortical steady potential.
Influence of age and brief auditory conditioning upon experimental seizures in mice
Authors: Iturrian W. B. , Fink G. B.
Published: January 2005

Audio‐sensitivity can be induced in strains of mice considered audio‐resistant by exposure to a brief auditory stimulation (60 sec at 95 db) at a critical age. Mice that had been audio‐conditioned were subjected to a battery of seizure‐evoking procedures and the responses interpreted in terms of neurophysiological mechanism. The effect of maturation on the development of sound induced, chemoshock and electroshock convulsion threshold and pattern was also studied. The pattern of maximal seizures induced by electroshock, pentylenetetrazol, and sound are remarkedly similar at a given age. The threshold for low frequency electroshock and for minimal pentylenetetrazol decreased with increased age and weight. There was no significant difference in maximal electroshock seizure threshold with aging, but duration of the seizure pattern markedly changed with increased age. Audio‐conditioning produced profound changes in the ontogeny of low frequency and chemoshock threshold, but maximal seizure threshold and pattern were unaffected. The audio‐sensitized CF# 1 mice differ in several ways from littermate. The oscillator mechanism of the audio‐sensitive mice is more easily discharged by electric and chemical stimulation, and there is an alteration in the neuro‐ontogenic pattern, and a decreased growth rate.
Effects of age and stimulus conditions on the emotional response of rhesus monkeys: Diferential responses to frustration and to fear stimuli
Authors: Bernstein Stephen , Mason William A.
Published: January 2005

Laboratory‐raised rhesus monkeys ranging in age from 3 to 25 months were tested for reactions to toys representing animals (“fear stimuli”) and to food frustration. The results indicate that these test conditions are associated with different response profiles and that the contrast between responses to fear and to frustration increases with age. Frustration in older animals is associated with regression to a less mature level of functioning.
Offspring survival, development, and operant performance following maternal ethanol consumption
Authors: Martin Joan C. , Martin Donald C. , Sigman Gary , Radow Barbara
Published: January 2005

Gravid Sprague‐Dawley‐derived rats received 35–40% of their total calories in alcohol during pregnancy or pregnancy and the 23‐day nursing period. Ethanol was administered both as the sole fluid source in a .1% saccharin solution and by twice daily subcutaneous injections. Two gravid control groups were matched for caloric and fluid intake to the experimental groups and received injections of the saline vehicle. The offspring were monitored from birth to adulthood on a variety of vital, developmental, and operant measures. Littermates of the behavioral offspring were sacrificed and necropsied at 1 and 12 months of age and the major organs examined for pathology.

Differences between alcohol and control groups were found for maternal weight gain, length of gestation, number of neonatal deaths, growth retardation of offspring to postnatal Day 72, date of eye opening, distance traversed on Day 15, contingent performance in the 1st week on continuous reinforcement, fixed ratio, and timing appetitive schedules, and on number of shock initiations and ability to discriminate contingencies on punishment schedules. No gross abnormalities were observed in the major organs at necropsy.
Polygraphic studies of kitten development: Sleep state patterns
Authors: McGinty D. J. , Stevenson M. , Hoppenbrouwers T. , Harper R. M. , Sterman M. B. , Hodgman J.
Published: January 2005

The sequence of developmental changes in sleep pattern organization was derived from 12‐hr recordings in 10‐, 20‐ and 40‐day‐old kittens. Each characteristic of sleep patterning exhibited a distinct maturational sequence. Earlier changes (10–20 days) included quiet sleep (QS) increments and somatic activity decrements; later changes (20–40 days) included emergence of EEG slow waves and spindles, decrements in active sleep (AS), and diminution of QS respiratory variability. Changes in the lengths of state epochs and the types of state transitions spanned the period studied. We suggest that the differential development of the characteristics of sleep patterns reflects differential maturation of distinct nervous system elements.
The role of motor learning and cage size in the early enrichment effect in mice
Authors: Henderson Norman D.
Published: January 2005

Three experiments with C57BL/10J mice examined the possible roles of cage size and simple motor practice as factors responsible for producing improved performance of animals reared in enriched environments. Neither factor was found sufficient to improve subsequent performance in a food‐seeking task. Mice reared in flat environments containing a variety of objects, but designed to prevent any climbing practice, out‐performed nonenriched animals on a task requiring extensive climbing activity.
Nocturnal sleep in isolation‐reared monkeys: Evidence for environmental independence
Authors: Reite Martin , Short Robert
Published: January 2005

Thirteen all‐night sleep recordings were obtained from 3 infant pigtailed (Macaca nemestrina) monkeys raised on a cloth surrogate mother under conditions of social isolation. Totally implantable biotelemetry systems were used to record the sleep physiology from the unrestrained animals. Sleep stages and night‐to‐night variability were virtually identical to values previously found in 8 mother‐reared group‐living infants. Sustained alterations in the early rearing environment, even though considerably modifying the organism's development, did not appear to result in differences in sleep organization.
Differential maternal retrieval of jaundiced versus non‐jaundiced gunn rat pups
Authors: Cahalan Kathleen J. , Graham Dee L.
Published: January 2005

Gunn rat dams were tested for differential retrieval of their jaundiced versus non‐jaundiced offspring in 2 experiments. In Experiment 1, in which testing took place every day from Day 1 to Day 8 postpartum, non‐jaundiced pups were retrieved significantly faster than jaundiced pups. In Experiment 2, in which testing took place every other day from Day 1 to Day 15 and the pups were weighed each test day, the order of retrieval of the 4 gender/genotype (jaundiced vs non‐jaundiced) classifications as found in the 1st experiment was replicated and the non‐jaundiced pups tended to be retrieved faster. Heavier pups were retrieved significantly faster than lighter pups, indicating that weight or size may be a cue to differential retrieval.
The interrelationship between thermal and olfactory stimulation in the development of home orientation in newborn kittens
Authors: Freeman Natalie C. G. , Rosenblatt Jay S.
Published: January 2005

The presence of a thermal gradient in the home cage and its use in home orientation was studied in kittens from shortly after birth to 2 weeks. Responses on a thermal gradient outside the home cage were also studied. With the home region and a freshly washed cage floor either cooled or warmed, kittens were placed in the adjacent corner or the home. In one study kittens chose between a cooled home and a warmed diagonal region. On a thermal gradient kittens exhibited thermotaxic turning and thermokinetic response. Kittens initially used either thermal or olfactory cues to reach the home but began to use only olfactory cues towards the end of the 1st week. Similarly, warmth in the home region caused “settling” during the 1st week but thereafter warmth and olfactory cues were most effective. Kittens chose the cooled home region more often than the warmed diagonal corner responding to olfactory over thermal cues.
Changes in cortical dendritic branching subsequent to partial social isolation in stumptailed monkeys
Authors: Struble Robert G. , Riesen Austin H.
Published: January 2005

Stumptailed monkeys were reared from 1 week after birth to 6 months of age in either a colony condition with the mother or in partial social isolation that allowed visual contact with the colony animals, but not physical contact. At 6 months of age the animals were killed and selected areas of the neocortex stained by the Golgi‐Cox method. Relatively nonspiney cells of Layer IV were drawn and analyzed for complexity of dendritic branching. Isolation‐reared animals had significantly decreased branching complexity in Motor I cortex when compared to the control animals. A transform of the data that related the number of branches to the number of previous branches showed a slight rearing effect in Somatosensory I cortex with the deprived animals having a lower rate of branching than the controls. We conclude that social isolation also includes a motoric deprivation that could account for these data.
Ultrasonic vocalization during social interaction and isolation in 2‐week‐old rats
Authors: Hofer Myron A. , Shair Harry
Published: January 2005

Two‐week‐old rats were found to emit very little ultrasound in their cage except during arrivals and departures of the mother, when average peak rates of approximately 1 ultrasonic pulse/rat/min were detected. However, when all pups except one were removed from the home cage, the remaining isolated pup emitted ultrasound at a mean rate of 12 pulses/min for at least 30 min. When young rats of this age were placed alone in an unfamiliar test area, the ultrasound pulse rate was approximately 25/min, whereas groups of 4 littermates in the same situation emitted only occasional ultrasonic pulses. If an isolated pup in the novel environment was allowed access to a single anesthetized littermate or mother this also significantly reduced the rate of ultrasound emission, whereas a warm clay model did not.
Comparative studies of the ultrasonic calls of infant murid rodents
Authors: Sales Gillian D. , Smith Jane C.
Published: January 2005

The ultrasonic calls of 10 species of murid rodents including 3 strains of house mice are described and the significance of interspecific similarities and differences is discussed. The calls of newborn murid rodents may be characterized by their gradual onset and cessation, their comparative lack of amplitude and frequency modulation, and, often, by the presence of only 1 frequency component. These common acoustic characteristics may be important in eliciting and/or maintaining various aspects of maternal behavior, both in and out of the nest.
Ontogenetic development of pentobarbital‐induced EEG pattern and sleeping time in rats
Authors: Staudacherová Dana , Mareš Pavel , Trojan Stanislav
Published: January 2005

The latency of onset and the duration of sleep induced by pentobarbital was studied in rats from 9 to 35 days of age, as well as in adult rats. Sleep latency was prolonged and sleep duration shortened with increasing age and maturation. Electrocorticographic changes after pentobarbital administration were studied in rats of 5–45 days of age and in adult rats. In rats 9 days of age or less the electrocorticogram manifested only depression of activity, whereas from the 12th day onward all characteristic barbiturate‐induced phenomena were registered: spindles, slow waves, and isolated spikes with suppression of background activity. Spindles were the most conspicuous of the pentobarbital‐induced phenomena and were the 1st to appear as a function of age, occurring only in the frontal areas at 12 days of age but in both frontal and occipital areas at 15 days of age. Frequency of the elements comprising spindles increased with from 2.5–3.5 c/sec in 12‐day‐old rats to 5–10 c/sec in adult animals. Barbiturate spindles could be used as a model for rhythmic thalamocortical phenomena even at early stages of development.
Contrast effects in the rat: A developmental study
Authors: Fagen Jeffrey W. , Shoemaker Gary E.
Published: January 2005

Two experiments investigated the exhibition and development of positive and negative contrast effects in the consummatory behavior of juvenile and adult rats. Over a 4‐day session, animals were given alternating 30‐sec presentations of 2 bottles containing either 32 or 4% sucrose solutions. In Experiment I, different groups of rats were tested both cross‐sectionally and longitudinally using a cohort‐sequential design. Cross‐sectionally, animals at all ages exhibited both types of contrast and demonstrated increasing positive contrast effects with greater age. Discrepancies between the longitudinal and cross‐sectional samples were found to be due to the repeated testing procedure of the former design. Experiment II replicated the positive and negative contrast effects in the juvenile animals, indicating that the processes responsible for contrast effects are operating in the rat at a very early age.
Developmental and genotypic effects on pituitary‐adrenal function and alcohol tolerance in mice
Authors: Swanberg Karen M. , Wilson James R. , Kalisker Albert
Published: January 2005

Lactating females of 2 lines of mice selectively bred for long (LS) and short (SS) ethanol‐induced sleep time (a measure of alcohol tolerance) consumed either tap water or 10% ethanol in tap water on Days 2–14 postpartum. Effects of genotype and neonatal treatment on offspring open‐field behavior, alcohol‐induced sleep time, and adrenocortical responsiveness to alcohol or saline injection were studied. The LS mice had higher ethanol‐induced sleep times than SS mice, and also higher plasma corticosterone levels following alcohol challenge. The LS mice also responded more to saline injection and to novelty stress, suggesting that they were generally more responsive to stressors than SS mice. Significant genotype‐dependent effects of neonatal treatment on (1) adrenocortical responsiveness to injection stress and (2) alcohol tolerance were noted. However, these 2 effects did not appear to be causally related. Neonatal treatment had no effect on open‐field activity or defecation in either genetic line.
Three parameters affecting interlitter variations
Authors: Woods Verne E. , Epstein H. T.
Published: January 2005

We studied 3 parameters affecting average body weight differences between mouse litters and have arrived at an approximation of the contribution that each makes to such differences. These parameters are birth weight, genetically based growth potential variations, and maternal competence. We have developed methods for controlling these parameters and show that through their application we can reduce litter‐average body weight differences from our normal value of more than 24% to about 3%. The vanished 21% consists of 12% due to differences in maternal competence, 6% due to growth potential differences, and 3% due to initial weight differences.
Do 16‐week‐old infants anticipate stimulus offsets?
Authors: Brooks Peggy R. , Berg W. Keith
Published: January 2005

Twenty alert 16‐week‐old infants were presented with 20‐sec tones at variable intertrial intervals for 10 trials while beat‐by‐beat heart rate responses were recorded to assess response at offset as well as onset of each stimulus. Consistent with past research, onsets elicited deceleratory responses which habituated and showed some evidence of dishabituation with a change in stimulus frequency on the last 2 trials. Offsets also elicited significant deceleratory responses overall, but inspection of pre‐offset heart rate suggested that deceleration in anticipation of the offset event appeared after a few stimulus repetitions and increased in magnitude over trials. However, individual variability was considerable and although the anticipatory response was significant averaged over all trials, the apparent increase over trials did not reach statistical significance. The evidence clearly indicates infants quickly process and act upon temporal information in a stimulus.
Auditory evoked potentials and auditory behavior following prenatal and perinatal asphyxia in rhesus monkeys
Authors: Mirsky Allan F. , Orren Merle M. , Stanton Linda , Fullerton Barbara C. , Harris Sandra , Myers Ronald E.
Published: January 2005

Two types of asphyxia were studied in monkeys, total asphyxia during mid‐pregnancy (94–98 days gestation) and combined partial and total asphyxia at term (165 days gestation). Auditory evoked potentials and the acquisition of 2 auditory discrimination tasks were studied in asphyxiated animals as well as in a group of controls. The brains of all asphyxiates were examined histologically. No auditory discrimination deficit was found in the asphyxiated animals; however, the auditory evoked potentials differentiated between control and asphyxiated animals, especially those with verified inferior colliculus damage.
Plasma corticosterone response to serotonin altering drugs in the 3‐day‐old rat
Authors: Grota Lee J.
Published: January 2005

Three‐day‐old rats were injected with various neurotransmitter altering agents to demonstrate a functional relationship between these drugs and plasma corticoid levels. Plasma corticosterone levels were increased after injection of methiothepin, methysergide, and 5‐hydroxytryptophan (5‐HTP), but were not changed by cholinergic, adrenergic, and dopaminergic compounds. Imipramine alone had no effects on plasma corticoids but in combination with 5‐HTP resulted in a more sustained response than 5‐HTP alone. A functional relationship between plasma corticosterone and serotonin receptors has been demonstrated in the 3‐day‐old rat. The presence of this relationship just after birth suggests the possibility that serotonin may be a mediator of early experience effects on later adrenocortical function.
Sleep apnea in hypoxic and normal kittens
Authors: Baker Theodore L. , McGinty Dennis J.
Published: January 2005

Frequency and characteristics of apneas were studied in 10‐, 20‐, and 40‐day old kittens during several days of exposure to 21%, 10%, or 7% oxygen atmospheres. Ninety‐seven percent of all apneas occurred during sleep or at transitions between sleep and waking states. Hypoxic kittens, compared to controls, had greatly decreased apnea frequency, but other characteristics of apneas did not differ significantly. Apneas in both control and hypoxic kittens were normal, stereotyped events and were not considered to represent pathological processes.

Evaluation of events preceding apneas indicated that a majority of apneas followed augmented breaths and/or brief arousals. We suggest that apnea, heart rate changes during apnea, and frequently concurrent transitions in sleep‐waking state may be causally related to these pre‐apnea events. The results of this study and a parallel study of human infants suggest that below‐normal apnea frequency may indicate hypoxemia and may be associated with higher risk for Sudden Infant Death Syndrome.
Developmental changes in visual orienting behavior to featural versus structural information in the human infant
Authors: Dineen John T. , Meyer William J.
Published: January 2005

Ten male infants, 3–4 months old, and 10 male infants, 6–7 months old, were habituated to a visual stimulus composed of both specific featural and structural information. After habituation, orienting magnitude (dishabituation) to changes in feature with structure controlled versus changes in structure with feature controlled was used as a means of measuring the infant's processing capacity. Results indicate that younger and older infants were habituated over the habituation trials but that younger and older infants differed significantly in dishabituation to changes in structure and feature information. The present findings support the hypothesis that feature and structure information are both independently important to visual processing in the human infant.
Maternal behavior, pup vocalizations, and pup temperature changes following handling in mice of 2 inbred strains
Authors: Hennessy Michael B. , Li Julia , Lowe Edna L. , Levine Seymour
Published: January 2005

A cross‐fostering design was used to examine maternal behavior, pup vocalizations, and pup temperature changes following an infantile handling procedure in C57BL/6J (C) and A/J (A) mice. In Experiment I, maternal behavior of C and A mothers after infantile handling differed in a number of ways irrespective of the strain of the foster pups. In addition, A pups were retrieved faster but licked less than were C pups by mothers of both strains. Handling appeared to increase the probability that strain differences would occur in that no differences between the lines, in either the behavior of the mothers or the capacity of the pups to elicit maternal behavior, were found during observations made just prior to daily handling. These observations also revealed that mothers of both strains treated same‐strain foster pups differently than they treated foster pups of another strain. In Experiment II, A pups were found to emit more ultrasound following handling than were C pups, suggesting that retrieval but not pup‐licking was stimulated by ultrasonic signals. Measurement of pup temperature during and following the handling procedure showed that (1) strain differences in ultrasonic signaling were not related to strain differences in the degree of hypothermia experienced by the pups; (2) recovery of body temperature following handling was slow for pups of both strains, and depended to some degree on the strain of the pup's foster mother; and (3) development of thermoregulation occurred more rapidly in C than A pups.
Recovery of the cortical evoked potential from auditory stimulation in children and adults
Authors: Surwillo Walter W.
Published: January 2005

The recovery of cortical evoked potentials to auditory stimulation was studied in a group of 12 young adults and 12 children aged 9.0–13.3 years. Subjects listened to single clicks and to pairs of clicks in which the interstimulus intervals (ISI's) varied, taking on values of 50, 100, 250, 500, 750, and 1000 msec. Average evoked potentials (AEP's) based on 50 repetitions were obtained to single clicks by coherent averaging and to the 2nd click of the pairs by automatically subtracting the evoked potential to each single click from the evoked potential to the corresponding pair and coherently averaging the remainder. In children, peak latencies of the P1, N1, and P2 components of the AEP to the 2nd click of the pairs increased significantly with decreasing ISI; in adults, latencies similarly increased except in the case of the N1 component. These increases were significantly larger in children than in adults, indicating that cortical recovery is slower in children and suggesting that cortical excitability in children may be lower. Peak latencies of the P1, N1, and P2 components of the AEP to single clicks were significantly longer (16–21 msec) in the children.
Sensory influences on homing of stunted rat pups
Authors: Fleischer Susan F. , Turkewitz Gerald , Finklestein Harris
Published: January 2005

The effects of 2 methods of restricting food intake—large‐litter rearing and rotation between lactating and nonlactating females—on sensory factors involved in homing to the nest by rat pups were examined. Homing was observed in the unaltered home cage, when olfactory cues were altered and when visual cues were altered. Stunted animals homed less in the unaltered cage than did well‐nourished controls as a result of a maturational delay. Prior to eye opening, stunted animals showed greater disruption of homing when olfactory cues were altered and after eye opening they showed greater disruption when visual cues were altered. These effects could reflect decreased sensitivity, an inability to use alternate cues, or behavioral disruption by novel stimulation. Nonnutritional factors were also found to affect homing as the 2 well‐nourished groups differed in their behaviors. These differences appeared to be due to animals reared in small litters maturing more slowly than animals rotated between females.
Echolocation by young bats on their initial and subsequent flights
Authors: Gould Edwin , Cooley Brian , Barnick Peter
Published: January 2005

This study documents developmental changes in the vocal reaction of bats to obstacles and describes the pulse patterns of young bats on their 1st and subsequent flights. The pulse repetition rate of young bats showed an increase just before the bats approached obstacles. This pattern differs from that of older bats. The distance at which the change in pulse repetition rate occurs is roughly twice as far from the obstacle in adults as it is in young bats. Even on their 1st flights young bats (25–29 days old) seemed to perform better than chance. This capability seems to be resistant to environmental manipulation during the preweaning period.
Subspecies differences in curiosity and general activity for developing squirrel monkeys
Authors: Roy M. Aaron , Hennig Charles W. , Hill Elizabeth M. , Walker Margaret L.
Published: January 2005

Curiosity and general activity characteristics in different squirrel monkey (Saimiri sciureus) phenotypes were assessed. Ten infant squirrel monkeys, representing 2 subspecies (Bolivian and Colombian) and both genders, were observed on 4 testing sessions during which novel and familiar objects were presented to each subject. No consistent object‐contact differences were found between subspecies or genders, but significant subspecies differences were found for the amount of time during each trial that the subjects climbed, remained stationary, vocalized, and showed abnormal behaviors. Familiar objects were handled most often. whereas novel objects that were shiny or yellow were moderately preferred.
Reactivity to light and development of classical cardiac conditioning in the kitten
Authors: Bloch Susan A. , Martinoya Carlos
Published: January 2005

Kittens studied from 7 days onwards revealed that the earliest age at which cardiac conditioning can be established is 30 days, after some 30 light‐electric shock associations. Older kittens showed both cardiac as well as motor conditioning. Animals younger than 21 days old had no well‐defined cardiac responses to the clearly nociceptive unconditioned stimulus so that no cardiac conditioning was established; neither did they show signs of motor conditioning. This failure could be due to immaturity of the cardiac‐emotional reactivity to nociceptive stimulation and immaturity of the neural structures involved in associative learning. Lack of reactivity to the light used as conditioned stimulus must be excluded because it already produced eye blink by 2 days of age. Moreover, a light‐dark preference test done during the 1st postnatal week showed that kittens are able to discriminate light from dark by 8 days of age.
Behavioral and adrenocortical reactivity in female mice following individual or group housing
Authors: Benton D. , Brain P. F.
Published: January 2005

Female “TO” strain mice were individually or group‐housed for different durations (7–196 days). Behavioral reactivity was assessed for 3 days in an open field and an emergence test. Plasma samples were later collected after 5 min exposure to ethyl ether vapor; these generated “stress” corticosterone values. “Basal” corticosterone titers were obtained from similar untested and unanesthetized categories of mice. “Ether‐stress” values were obtained from a limited number of mice subjected to ether anesthesia but no behavioral testing. Neither the basal nor the stress adrenocortical activities of the 2 housing categories differed. Open‐field ambulation increased with longer durations of isolation, whereas for grouped mice it remained approximately constant. Individually housed mice had significantly lower defecation scores and longer emergence times than group‐housed mice. In sum, little support was provided for the view that isolation is stressful.
Effect of reciprocal cross‐fostering on aggression of female mice toward lactating strangers
Authors: Haug Marc , Pallaud B.
Published: January 2005

Reciprocal cross‐fostering of mice was carried out between an inbred strain (C57 BL/6) in which the female showed a particular form of aggression toward lactating female intruders, and a strain (C3H/He) which proved to lack totally this type of attack. In adulthood, cross‐fostered females of the 2 strains and their controls were submitted to a series of aggression tests. They encountered in the test situation either a strange lactating female of their own strain or one of the foster strain. No differences in aggression measures were found between cross‐fostered animals and controls, indicating that experiential factors (viz., cross‐fostering) were without effect.
Postparturitional reestablishment of pup cannibalism in female gerbils
Authors: Elwood Robert W.
Published: January 2005

Nonbreeding female Mongolian gerbils readily cannibalize all accessible pups. Among breeding females this behavior ceases a few days prior to parturition. If the litter remains with the female, cannibalism of newborn test pups returns between 11 and 20 days postpartum. If the litter is removed a few hours after parturition, however, 40% of the females will cannibalize on Days 1–5 and 72% will cannibalize on Days 6–10 postpartum. Thus, the presence of a litter appears to suppress pup cannibalism. The evidence suggests that the replacement of a litter 6–10 days old with newborn pups can prolong the suppression of pup cannibalism.
Serotonin regulation of corticoid secretion in infant rats
Authors: Grota Lee J.
Published: January 2005

The plasma corticosterone response to various doses of serotonin and 5‐hydroxytryptophan was studied in the 3‐day‐old rat. The maximum response to both drugs occurred 60 min after injection. Increased corticosterone concentration was observed at lower doses of serotonin than of 5‐hydroxytryptophan. The effects of serotonin injection on Days 1–7 after birth on the plasma corticosterone response to 3 min of novelty stimulation at weaning was also studied. Serotonin treatment resulted in reduced adrenocortical reactivity which was reduced further when fluoxetine was given prior to the serotonin. Shocking rat pups on Days 1–7 also reduced adrenocortical reactivity and fluoxetine prior to shock further reduced adrenocortical reactivity when administered twice per day.
Brightness effects on color pecking preferences in dark‐hatched domestic chicks
Authors: Fischer Gloria J. , Davis Stephen J.
Published: January 2005

Color pecking preferences in day‐old, dark‐hatched domestic chicks of 2 breeds were studied as a function of (1) target luminance (dim, medium, or bright) when testing was in darkness and in the light (Experiments I and II); (2) method of equilibrating target brightnesses (i.e., objectively or subjectively; Experients III and IV); and (3) ambient brightness (dim, medium, or bright; Experiment IV). White Leghorns were found to peck sooner and more often than New Hampshires. Under all conditions of target and ambient brightness, results revealed the previously reported bimodal (V‐shaped) color preference function with peak preferences in the blue‐violet and orange regions of the spectrum and minimal at green. The only brightness factor that affected the V‐shaped function was dark‐adapted vs light‐adapted viewing, that is, the chicks showed a slight shift away from red and/or a slightly more negative slope with light adaptation.
Effect of differential rearing on brain, liver and adrenal tissues
Authors: Uphouse Lynda L. , Brown Harold
Published: January 2005

Brain, liver, and adrenal weights were measured in rats differentially reared from 28–60 days of age. Relative to the standard colony rats, enriched rats had heavier brains but lighter livers. Relative to the standard animals, impoverished rats had heavier adrenals. These results confirm differential rearing influences on organs other than the brain.
Effects of restriction of maternal uterine blood supply on postnatal conditioning of heart rate and behavioral development in dogs
Authors: Francisco David L. , Fitzgerald Robert D. , Lawson Maralee S. , Potter D. Mark , Metcalfe James
Published: January 2005

An examination was made of the heart rate responses during aversive classical conditioning of 5‐ to 6‐week‐old Labrador puppies exposed to restricted maternal uterine blood supply during gestation. The direction of the heart rate responses of the treated puppies was consistently decelerative, whereas nontreated controls showed both decelerations and accelerations. The absence of accelerative heart rate changes, combined with the observed depression of base level heart rate and attenuated emotional behavior in the experimental animals relative to controls suggests that uterine blood supply insufficiency may have impaired normal autonomic development in utero.
Alterations of maternal behaviors of female rats caring for malnourished pups
Authors: Fleischer Susan F. , Turkewitz Gerald
Published: January 2005

The maternal care received by rat pups malnourished by being rotated between lactating females and nonlactating foster mothers was examined. During the 1st 2 weeks after birth there were no differences in maternal care, but during the 3rd week females caring for pups fed only 8 hr daily nursed more and built better nests than females caring for pups fed 16 or 24 hr. These differences in maternal care may interact with and diminish any effects of nutritional deprivation in the pups.
Short‐term juvenile crowding arrests the developmental formation of dendritic spines on tectal interneurons in jewel fish
Authors: Burgess J. Wesley , Coss Richard G.
Published: January 2005

Development of jewel fish tectal interneurons was measured as a function of crowded development. The number of dendritic spines on the apical dendrites of pyriform interneurons was counted in the stratum album centrale plexiform layer because previous research indicated that this was the region in which both social deprivation and acute juvenile crowding produced neuronal deficits. Results showed that 100‐ and 130‐day‐old uncrowded juveniles had spine densities equivalent to 160‐day‐old juveniles crowded at 15 fish/3.6 liter for 60 days. Thus, no spine formation occurred after the onset of crowding. Sibling 160‐day‐old juveniles reared in the uncrowded condition (1 fish/4.6 liter) had already acquired the normal complement of spines exhibited by 4‐year‐old adults reared at low density (1 fish/25 liter). These results show that acute crowding can arrest the normal course of neuronal development in juvenile jewel fish.
Right‐hand preference facilitated by rightward turning biases during infancy
Authors: Liederman Jacqueline , Coryell Jane
Published: January 2005

A rightward turning bias is the earliest human behavioral asymmetry and may be a precursor of handedness. Head‐turning affects arm position as part of the Asymmetric Tonic Neck Reflex (ATNR). The hypothesis was tested that turning biases operate in coordination with the ATNR to promote handedness by measuring reflex behavior during turns in the preferred vs nonpreferred direction. Twenty infants were filmed during spontaneous movement and during the following factorial design: head turned left vs right; voluntarily vs passively; 30° vs 70°. The incidence, strength, and duration of the ATNR were least when the child turned toward his/her preferred side. When right‐preference children turned rightward, the occurrence of the ATNR was no better than chance. Thus, a child can orient toward the right hand with minimal intrusion of the ATNR upon limb position, perhaps promoting right‐handedness.
Jewel fish retain juvenile schooling pattern after crowded development
Authors: Coss Richard G. , Burgess J. Wesley
Published: January 2005

Juvenile jewel fish were crowded between 100 and 160 days of age (15 fish/3.6 liters) in a double‐walled aquarium sharing water flow with uncrowded siblings (15 fish/69.4 liters). Photographs of schooling in a 73‐liter aquarium were made after 30 and 60 days of crowding. Distances maintained between each fish and its 1st–5th nearest neighbors and orientation angles between 1st nearest neighbors were measured. After 30 days, crowded juveniles maintained significant nonrandomly aggregated distances to their 1st–5th neighbors, spacing significantly closer than uncrowded siblings. After 60 days, crowded juveniles maintained both closer, nonrandom distances to 1st–5th neighbors and significantly more parallel orientation to 1st nearest neighbors. Thus, whereas uncrowded juveniles followed the normal developmental pattern of dispersion, crowded siblings retained juvenile spacing behavior.
A fit mouse is a hoppy mouse: Jumping behavior in 15‐day‐old Mus musculus
Authors: Henderson Norman D.
Published: January 2005

An analysis of a juvenile hopping response from an 8 × 8 diallel cross is used to demonstrate the experimental genetic approach for testing presumed adaptive fitness of behaviors in developing organisms. In accordance with predictions, the explosive jumping behavior exhibited by 15‐day mice is characterized by a pattern of genetic dominance toward high expression of the trait. Wild mice show even more vigorous responses, indicating that selection pressures maintaining high responding have been relaxed during domestication. These data suggest some applications and limitations of genetic methods for the study of behavioral evolution as related to development.
Auditory imprinting in domestic chicks during tonic immobility
Authors: Sigman Stephen E. , Prestrude Albert M.
Published: January 2005

In the present study we attempted to determine whether the characteristic unresponsiveness of animals during tonic immobility is due to sensory or motor inhibition. Specifically, we exposed domestic chicks to an auditory imprinting stimulus during tonic immobility. Seventy‐five White Leghorn chicks were tested in 1 of 5 conditions: (1) immobilized and imprinted; (2) restrained but not immobilized, and imprinted; (3) imprinted only; (4) immobilized but not imprinted; and (5) neither immobilized nor imprinted. Chicks in the 1st 3 groups all imprinted to the same degree in that they did not differ in median run times in a straight alley with the imprinting stimulus. These results demonstrate that chicks do process auditory stimuli during tonic immobility and the reduced responsiveness observed during tonic immobility is due mainly to motor inhibition.
Behavioral correlates of physical and neuromotor maturity in adolescents from different environments
Authors: Waber Deborah P. , Bauermeister Martin , Cohen Carolyn , Ferber Richard , Wolff Peter H.
Published: January 2005

The relationship between neuropsychological performance (sequencing and visuospatial processing) and neuromotor and physical maturity was investigated among ninety 14‐ and 15‐year‐old boys selected from 3 socioeconomic backgrounds: upper middle class, white collar, and blue collar. Sequencing was measured by the Stroop Word and Color Test and by stability of rhythmic finger tapping; visuospatial processing was measured by a locomotor mazes task. We had predicted that rate of maturation would be correlated positively with sequencing and negatively with visuospatial performance independent of socioeconomic background. The correlations between neuropsychological performance and maturational status were in the directions predicted, but the appearance of these relationships was not independent of socioeconomic status. In the upper middle class group, visuospatial processing was negatively related to physical maturity; in the white collar group, motor sequencing was positively related to physical maturity; and in the blue collar group, all the sequencing measures were positively related to neuromotor maturity.
A response adjustment procedure for assessing stimulus preference in preweanlings
Authors: Rose Guenter H.
Published: January 2005

A nonlearned, response‐dependent testing technique entitled Response Adjustment Procedure (RAP) is introduced. The technique is designed to circumvent or reduce the use of a learning paradigm in very immature animals and utilizes age and species‐appropriate motor behavior. Initial data on the onset of light avoidance in rats are presented to illustrate the method.
Effect of brain growth stages on T‐maze acquisition in mice
Authors: DeLuca John , Bischoff Hank , Kelman Stanley , Lavooy Maria , Phillips Tamara , Posch Robert , Wolf Patricia , Hahn Martin
Published: January 2005

Recently, it has been shown that brain growth is characterized by periods of especially large increases in growth, with “plateaus” in growth between these “spurt” periods. In humans, these spurts in brain growth are correlated with spurts in mind growth, collectively termed phrenoblysis. Brain growth spurts in rodents occur at 0–6, 8–12, and 17–23 days of age with plateaus in‐between. We examined two questions. First, are there differences in learning ability associated with spurts and plateaus in brain growth? Second, can learning during these stages be altered through genetic and environmental manipulations? We employed the high and low lines of the Fuller brain weight selection mice, which are known to have different developmental patterns, and early handling procedures, known to alter growth rates. The results showed that animals tested during a proposed brain growth spurt were superior to animals tested during a brain growth plateau in learning a shock‐escape T‐maze.
Urinary odors and size protect juvenile laboratory mice from adult male attack
Authors: Taylor George T.
Published: January 2005

For a portion of their ontogeny, the juveniles of many mammalian species appear resistant to aggressive attack by adult male conspecifics. The possibility that urinary odors and small size contribute to this immunity from attack was investigated with C57/Bl, A/J, and DW/J laboratory mice. The results of the 1st of 6 experiments were that juvenile mice of both genders evoked great curiosity from aggressive resident male adults, but juveniles were rarely attacked. In Experiments II and III, exchanging urine between juveniles and adult males suggested that juveniles possess a distinctive odor. In Experiments IV–VI, dwarf adults, normal‐sized adults, and juveniles were placed with aggressive adult male residents. The dwarf males were attacked, but not as severely as normal‐sized male intruders (Experiment IV). The dwarf males, however, evoked more aggressive behavior than juveniles (Experiment V), and juveniles with the odors from either normal‐sized or dwarf adult males were attacked more readily than non‐odorized juveniles (Experiment VI). These data suggest that both odor and size contribute to the juveniles' immunity from attack.
Appetitive conditioning in neonatal rats: Conditioned orientation to a novel odor
Authors: Johanson Ingrid B. , Hall W. G.
Published: January 2005

These experiments document a form of early appetitive learning in rats obtained using classical conditioning procedures. Some of the special determinants of this conditioning are described, as well as ontogenetic changes in the effectiveness of training procedures. Learning was apparent when deprived 3‐ and 6‐day‐old rats oriented to and maintained contact with a novel and normally aversive odor after this odor had been paired with oral infusions of milk (Experiment I). The effectiveness of the conditioning procedures depended on the temperature at which pups were trained (Experiment IB). Moreover, the reinforcing properties of milk infusions depended on deprivation (Experiment IC). This conditioned change in responsiveness to odor was specific to the odor that had been paired with milk (Experiment II) and was retained for at least 24 hr (Experiment III).