bluuebunny/crossref_metadata_2025 huggingface dataset:
Age differences in central nervous effects of visual deprivation in the dog
Authors: Fox M. W. , Inman O. , Glisson S.
Published: January 2005

Visual deprivation in dogs during the first 5 weeks of life resulted in marked structural, biochemical, and electrophysiological changes which were not apparent in dogs similarly treated between 5 and 10 weeks of age or for 5 weeks as adults. These findings are discussed in relation to the period of integration, when structuro‐functional relationships of neural elements begin to reach adult‐like levels of organization. It was postulated that lack of stimulation of a sensory modality during this period would result in arrested development of the system so treated. This hypothesis was partially supported; although there was complete visual deprivation, some neuronal and myelin development occurred independent of visual stimulation. Visual evoked potentials were markedly abnormal in the youngest age group only. The findings suggest a “sensitive” period in the pathodevelopmental sense; development of a particular system is retarded if stimulation is inadequate. This period corresponds to the period of integration when structuro‐functional organization of component systems of the central nervous system occurs.
Maturation and topography of the auditory evoked response of the prematurely born infant
Authors: Weitzman Elliot D. , Graziani Leonard J.
Published: January 2005

The behavioral, EEG, and auditory responses have been studied during the maturation of prematurely born infants. It was found that: (1) The less mature the infant, the less time spent in a quiet sleep state. As the infants matured, periods of quiet sleep occurred for longer durations and interrupted the active sleep phase more frequently. (2) The EEG pattern of young infants (23–26 weeks estimated conceptional age [ECA]) consisted almost entirely of an “intermittent” pattern. As maturation progressed, this “intermittent” pattern became more closely associated with periods of quiet sleep. The continuous pattern appearing at approximately 29 to 31 weeks (ECA) was increasingly associated with an active sleep phase; by 34 to 35 weeks (ECA), the correspondence between EEG pattern and sleep state was more constant. (3) All infants regardless of conceptional age responded to the auditory stimulus from all recorded areas of the scalp. A sequence of wave patterns of the auditory evoked response was noted as a function of maturation. The young infants had a large, negative, long‐latency (180–270 msec) wave diffusely over the scalp. As maturation progressed, a series of negative‐positive‐negative components was recognized. The evoked response patterns changed wave latency‐amplitude relation as a function of both age and scalp topography. (4) The latency of the evoked response waves N1 and P2 were consistently greater during the intermittent, compared to the continuous EEG pattern in infants 34 to 40 weeks age post conception. (5) A small, (early ∼ 15 msec) auditory evoked response was recorded from the ear electrode and is probably of muscle origin. This early muscle response was augmented when the baby was awake and crying, intermediate in amplitude during an active sleep period, and barely detectable or absent during quiet sleep.
Effects of maternal essential fatty‐acid deficiency on neonatal rat brain
Authors: Steinberg Alan B. , Clarke Gregory B. , Ramwell Peter W.
Published: January 2005

Female weanling rats were raised to sexual maturity on either a normal stock diet or an essential fatty‐acid (EFA) deficient diet, and then bred. Brain weight and lipid composition of the offspring from these animals were measured as part of an investigation into factors contributing to the early death of EFA‐deficient progeny. Lactation failure does not seem to be an adequate explanation of the early deaths since the dead EFA‐deficient offspring frequently have milk in their stomachs. Maternal behavior including nesting was lacking, however, in EFA‐deficient dams. The EFA‐deficient brains weighed less than normal neonatal brains, and frequently had subdural hemorrhaging. Relative to body weight, however, some “sparing” of the brain was apparent. Total brain sterol concentration was not measurably different, but fatty‐acid composition of total brain lipid and phospholipid was. The EFA‐deficient offspring had relatively less arachidonate and other EFA‐related fatty acids, while the proportion of trienoic acids, principally 20:3 and 22:3 was increased considerably. In phosphatidyl ethanolamine, the proportion of 16:0 was particularly elevated in the EFA‐deficient brains. The results are discussed in relation to the integrity of myelin and the synthesis of prostaglandins, as possible factors in the premature death of EFA‐deficient progeny.
Temperature reduction in neonatal mice: Effects on later behavior
Authors: Haggett Burton N. , Werboff Jack
Published: January 2005

The effects of body temperature reduction in neonatal C57BL/6J mice were studied in 2 experiments. Experiment I investigated the development of the thermoregulatory response of mice from 1 to 15 days of age in their nest and in an ambient environment of 22°C. The experimental conditions could then be specified to produce body temperature reduction of either 5 or 10°C for 10 min from day 1 through 15. In Experiment 2, effects of these body temperature reductions at day 1 to 5, 6 to 10, or 11 to 15 on subsequent behavior at 30 and 70 days of age were studied. Three control groups (handled, non‐temperature maintained; handled, temperature maintained; and nonhandled) were treated at the same age periods. Behavioral tests were open field, water runway, water maze (preference) and single‐alternation problem, and water submersion. No consistent behavioral effects could be attributed to body temperature reduction or to age at treatment in infancy. Mice receiving body temperature reduction of 5 and 10°C, or handling (with or without body temperature reduction) behaved differently from nontreated subjects on latency and activity measures in an open field; on the latency measure in the water maze (preference) test; on the errors and days to criterion measures in the single‐alternation water maze; and in time‐to‐submersion in water. The behavioral alterations of the treated groups could be interpreted to represent reduced emotionality, and improved performance and learning ability resulting from the neonatal experiences.
Stereotaxic atlas of the infant rat hypothalamus
Authors: Valenstein Thelma , Case Barbara , Valenstein Elliot S.
Published: January 2005

A sterotaxic atlas of the hypothalamus of the 1‐, 7‐, and 14‐day‐old rat is presented. Ancillary techniques for anesthetizing these young animals, mounting the neonates in the instrument, and special histological considerations are discussed.
Partial interocular transfer of visual discriminations in cats
Authors: Schissler Dale R. , Riesen Austin H.
Published: January 2005

Normally expected visual behavior in the cat, following monocular training, is a full stimulus equivalence when the second eye is used in transfer tests. This expectation has not been tested severely by using competing habits trained separately for each eye. Two groups of cats, normal and with striate cortex ablated, were tested under conditions of training in which opposing habits were used with the two eyes. Using intensity discrimination habits it was found that normal and operated cats failed to show complete interocular transfer. The normal group exhibited more transfer (greater conflict) from one eye to the other than did the operated group. It is suggested that interocular equivalence is partly dependent upon the organism's having learned to use similar kinds of visual cues with both eyes. The data also support the idea that encephalization increases binocularity and interocular equivalence.
Effects of auditory stimulation and litter size upon subsequent emotional behavior in the rat
Authors: Lore Richard , Avis Harry
Published: January 2005

In Experiment I, rat litters that contained 3 or 9 pups were exposed to either silence, 55 db, or 90 db radio sounds during the preweaning period. The dependent variables were (a) measures of nest height and nest quality, (b) infant mortality, (c) weaning weights, and (d) activity and defecation on 3 open‐field trials. Small‐litter subjects (Ss) were heavier at weaning but their open‐field performance was virtually identical to that of large‐litter Ss. The 55‐db group was significantly more active on the 2nd and 3rd open‐field trials. In the 2nd experiment, litters of 3 and 9 pups were exposed to 55 db or 90 db radio stimulation throughout the preweaning period. Results similar to those of the first experiment were obtained. Both studies indicate that litter size variations do not influence subsequent emotional behavior, whereas the degree of auditory input during preweaning can have marked effects upon emotional development.
Behavioral effects of neonatal irradiation of the cerebellum. I. Qualitative observations in infant and adolescent rats
Authors: Wallace Robert B. , Altman Joseph
Published: January 2005

The cerebellum of rats was irradiated from birth with daily doses of 200r for 1, 2, 3, 4, 5, 8, and 10 days. The animals were killed at fixed periods after irradiation and at various ages for histological evaluation of the cerebellum or they were permitted to survive for a prolonged period for behavioral testing. Gross measurement indicated that anteroposterior growth of the cerebellum was retarded as a function of the number of doses delivered except in animals that received a single dose of of 200 r. A number of pre‐ and post‐weaning qualitative behavioral observations (tremor, ataxia, level of activity) correlated with the retardation of cerebellar development produced by the irradiation schedules, though some behavioral recovery was noted in the older animals.
Experimental modification of brain weight and behavior in mice: An Enrichment Study
Authors: Collins Ruth‐Ann
Published: January 2005

The effects of environmental enrichment and isolation on cortical weight and learning ability were measured in mice from lines selectively bred for high and low brain weight and from an unselected control line from the same foundation population. Animals from these selected lines differed not only on brain weight, but on discrimination task performance as well. Isolated and enriched animals did not differ in cortical weight, nor was there any significant interaction of rearing conditions with lines. Those animals reared in enrichment were superior to those reared in isolation, both for initial acquisition and for number of reversal tasks performed on a water maze discrimination task. High brain weight animals did not differ from low brain weight animals on initial acquisition across treatment conditions. However, high brain weight animals made significantly more reversals within the testing period. The high, control, and low brain weight animals did not order themselves linearly on the behavioral measures: control line animals performed poorest for both initial acquisition and number of reversals.
Strain‐Specific effects of chronic prenatal irradiation in mice
Authors: Simeonsson Rune J. , Meier Gilbert W.
Published: January 2005

Female mice of the BALB/c and C57BL/6 strains were exposed to ionizing radiation 60Co at a rate of 89 R/hr for 15 days of the gestation period (total dose 320 R). Control animals were sham‐irradiated and the offspring produced were tested at 30 or 105 days of age for open‐field behavior and avoidance conditioning. The magnitude of the prenatal irradiation effect was found to be both strain and sex specific: the open‐field activity of irradiated BALB/c mice of both sexes and irradiated C57BL/6 males was significantly higher than that of control animals; the avoidance conditioning of irradiated BALB/c males was greater than that of any other group. Strain specificity was also seen in the viability and morphology of offspring as well as in maternal reproductivity, suggesting that irradiation may have both direct and maternally‐mediated effects on fetal development.
Effects of adrenalectomy on maternal behavior in rats
Authors: Thoman Evelyn B. , Levine Seymour
Published: January 2005

One week prior to mating, female rats were adrenalectomized or sham‐operated and, immediately following parturition, each was given a foster litter of 10 newborn pups from a mother in the same group. Retrieving measures at the time of fostering revealed no significant differences between the 2 groups. Over 16 days of maternal behavior observations the adrenalectomized mothers spent more time in the nest, more time in an active suckling position, and tended to keep the pups in the nest over a longer period of time. These results provide evidence that a functioning adrenal is not necessary for the initiation or maintenance of maternal responsiveness in rats.
Experience and the orb web
Authors: Reed Charles F. , Witt Peter N. , Scarboro Mabel B. , Peakall David B.
Published: January 2005

Cross spiders (Araneus diadematus CI.) were confined in tubes for between 3 weeks and 194 days, from the period preceding building of a first web, or as adults. The first webs built after release were invariably found to be significantly smaller (shorter thread and smaller catching area) than those of littermates raised in large frames. The ampullate glands of nonbuilders were found to incorporate 14 C alanine at a lower rate than those of regular web‐builders. Pulling thread from glands repeatedly before release, or allowing animals to build several webs, brought speed of silk synthesis and size of webs to control values: this indicates that scarce silk supply is the cause for small webs after confinement. No differences in web size and pattern were found between mouth‐fed and web‐fed spiders, if animals were otherwise raised the same way. But adult spiders who had never been allowed to catch prey on the web disregarded flies in their webs. Differences in plasticity of web‐building and prey‐catching behavior are discussed.
The influence of nutrition on neural and behavioral development. II. Growth of body and brain in infant rats using different techniques of undernutrition
Authors: Altman Joseph , Das Gopal D. , Sudarshan Kiran , Anderson Jon B.
Published: January 2005

Two techniques were used for producing undernutrition in infant rats and their effects on the growth of the body and the brain were investigated. In one procedure, the mothers were fed ad lib and the size of their litters was varied (5, 10, and 16 pups). In the other, litter size was kept constant at 8 pups per mother but during lactation the mothers either were fed ad lib or their food intake was restricted to 40% or 20% of normal consumption. The latter procedure was found to be the more reliable way of producing experimental retardation in the growth of the body and of the brain during the preweaning period. The failure of both procedures in producing retardation of brain growth during the first week of life is discussed.
Effects of temperature on ultrasound production by infant albino rats
Authors: Allin John T. , Banks Edwin M.
Published: January 2005

The influence of temperature on production of ultrasonic distress calls by infant Wistar rats was investigated. Call rates of pups aged 2 to 18 days were recorded at ambient levels chosen to provide for a decline in body temperature (2° and 20°C), an increase in body temperature (40°C), and minimal changes in body temperature (35°C). Isolated pups were exposed to each temperature for 4 1/2 min, during which ultrasounds from 30 to 50 kHz were monitored. Low ambient temperatures consistently elicited high rates of ultrasound production, although call rate was not inversely proportional to ambient temperature. High ambient temperatures were ineffective in eliciting increased calling. Calling was infrequent at the neutral temperature, indicating that nonthermal stimuli associated with the isolation condition are relatively ineffective in eliciting ultrasound production. Decline in call rate beyond 8 days of age is apparently related to developing homeothermy which reduces the survival value of distress calls in attracting the mother.
Some developmental observations on the effects of prolonged deprivation of Low‐voltage Fast‐wave sleep in the deermouse, peromyscus maniculatus Bairdi
Authors: Mitler Merrill M.
Published: January 2005

Previous electrophysiological work with adult deermice (P. M. Bairdi) (Mitler & Levine, 1970) indicated that: three states of arousal could be reliably distinguished: low‐voltage, fast‐wave sleep (LVF), high‐voltage, slow‐wave sleep (HVS), and waking (W);low‐electromyograph (EMG) activity was concomitant with LVF; and time in LVF was radically reduced in mice perched above a shock‐grid on a pedestal too small to permit total loss of muscle tonus. A preliminary aim of the present research was to gather electrophysiological data on juvenile deermice to construct some estimate of developmental sleep changes. Electrocorticograph (ECoG) and (EMG) records, from three 20‐day‐old mice while motionless with eyes closed, also reflected LVF, HVS, and W, but in proportions different from those reported by Mitler and Levine. Juvenile mice showed 1/3 more LVF than did adults. The main goal of this research was to explore the effects of long‐term LVF‐deprivation on juvenile and adult mice. Litters were selected at either 20 or 53 days of age. Littermates were assigned to one of four 14‐day treatment conditions in an Age Treatment design with 3 subjects per cell. The 1st treatment, LVF‐deprivation, consisted of perching on a pedestal over a shock‐grid. The remaining 3 conditions ran simultaneously with the former. Mice in the yoked control condition had approximately equal free movement volume as those mice restricted to the pedestal, and were “yoked” to those animals with respect to shock. Mice in the sleep deprivation condition were confined to a treadmill in motion 19 of each 24 hr. Finally, mice in the isolated condition were caged alone. After treatment, animals were placed in activity recording cages for 21 days.

Dependent variables included body weight before treatment, after treatment, and after procedure, brain weight, brain/body weight ratios, activity, and regularity of activity for the 21 days posttreatment. Major findings indicated that animals LVF‐deprived from 20 to 34 days of age were more active than controls while animals LVF‐deprived from 53 to 67 days of age were less active than controls. There were no interpretable differences among treatments in regularity of activity, body weight, or brain weight. Results were discussed in terms of input requirements for CNS development and/or maintenance. Directions for future research were suggested.
Activity of Purkinje cells, parallel fibers, and climbing fibers in the developing rabbit cerebellum
Authors: Delhaye‐Bouchaud N.
Published: January 2005

A study has been made of the activity of Purkinje cells, parallel fibers, and climbing fibers in 120 rabbits aged from a few hours to 20 days. Spontaneous simple spike activity due to activation by the mossy fiber‐granular cell‐Purkinje cell system has been found, and also a complex spike related to direct activation by the climbing fibers from the first few hours of life. Statistical analysis of unit discharges shows that there is a general linear increase in their frequency with age. The presence of a propagated spike in the parallel fibers and of complex discharges in the Purkinje cells in response to stimulation of afferent climbing fibers confirms that a large part of the cerebellar synaptic system is operative from the time of birth.
Behavioral effects of neonatal irradiation of the cerebellum. III. Qualitative observations in aged rats
Authors: Wallace Robert B. , Daniels Craig E. , Altman Joseph
Published: January 2005

Rats aged 2–2½ years, whose cerebellums were focally irradiated with a variable number of daily does of 200 R X ray during infancy were tested on a number of qualitative behavioral observations (motor activity, ataxia, tremor, and emotionality). We noted that many of the behavioral abnormalities, in evidence in the preweaning observations which had then disappeared, reappeared again in old age. A treatment‐senescence interactions was suggested to account for the data.
Arousal defect in L‐phenylalanine fed rats
Authors: Hole Kjell
Published: January 2005

Rats fed a 5% L‐phenylalanine diet from 28 days of age were tested 33 to 44 days later (61–72 days old) for spontaneous alternation, habituation to auditory stimulation, and passive avoidance. In spontaneous alternation and passive avoidance tests there was no significant difference from control rats. Habituation was faster than in the controls, interpreted as an inability to sustain arousal and attention. This may be a basic behavioral deficit in L‐phenylalanine fed rats, accounting for deficits reported in more complex learning tests. Phenistix tests for phenylpyruvic acid in the urine were positive only during the first 4 weeks the 5% diet was fed. The behavioral deficit was present even after this period. To reestablish positive Phenistix tests the excess L‐phenylalanine in the diet had to be raised to 10%. This diet severely affected the nutrition of the animals.
Effects of differential preweaning social isolation on emotional reactivity and stress tolerance in the rat
Authors: Lorenz Robert J.
Published: January 2005

The effects of differential preweaning social isolation of rats during Days 17–22 on the development of muricide, open field behavior, and starvation stress tolerance were examined. Four weaning isolation groups were used in order to separate the effects of maternal and littermate isolation during this period. EMLI was deprived of maternal and littermate contact; EMI, maternal contact; and ELI, littermate contact. NWI rats were isolated on the day following normal laboratory weaning. The results indicated a marked decrease in muricide in response to maternal isolation (EMLI and EMI) and a slight decrease in response to littermate isolation. In the open field the maternally isolated rats were more active than the other groups and exhibited less defecation. There were, however, notable differences between EMLI and EMI. EMLI was more active than EMI in the open field and exhibited an increase in activity over the 4 testing periods while EMI, ELI, and NWI decreased activity. EMLI was clearly hyperactive during muricide testing while EMI was the least active. EMI rats weighed less than those in the other groups on Days 35, 50, and 100 but survived terminal food deprivation the longest. Significant differences in nonstressed adrenal gland weight were observed among groups but did not appear to correlate with any of the other measures. Terminal starvation eliminated these differences. Starvation also induced muricide in nonkillers in each of the groups. NWI rats appeared to be most easily converted and exhibited more consistent muricide than the other groups. These results are discussed in terms of a theory of altered forebrain regulation of emotional reactivity in response to preweaning stress and isolation.
Development of adult‐like open‐field behaviors in young retinal‐degenerate C3H mice
Authors: Nagy Z. Michael , McKay Christine S.
Published: January 2005

Retinal degenerate C3H mice were tested in the open field under 2 illumination conditions before, during, and after the ages at which the early degenerate process occurs to determine whether the progressive destruction of the retina would result in the loss of brightness discrimination ability. From data collected on mice tested at 10, 14, 18, 22, 26, and 30 days of age, longitudinal and cross‐sectional analyses were performed upon activity and and defecation scores to separate the effects of prior test experience and age at testing. Whereas illumination differences had no effect upon defecation scores, activity differences under the 2 illumination levels formed an inverted U‐shaped function, with the greatest activity difference at 22 days of age. Prior experience was found to have no effect upon total activity scores at a particular age, although it did affect the pattern of activity over test days at the later ages. Naive animals tended to defecate less on their first day than did animals of the same age with prior test experience. The results of this experiment provide further evidence that retinal degeneration does not lead to complete blindness in this mouse strain, although it does lead to a loss of brightness discrimination ability following the degeneration period.
Development of 24 hour retention of escape learning in neonatal C3H mice
Authors: Nagy Z. Michael , Misanin James R. , Olsen Peter L.
Published: January 2005

The development of 24‐hr memory of an escape response in neonatal C3H mice was examined in 2 experiments. In experiment 1, separate groups of mice received 25 trials of escape training for 3 consecutive days (24 hour Inter‐session‐interval) beginning at 5, 7, and 9 days of age. Several different measures demonstrated witin‐session improvement for all ages on all test days. However, between‐session improvement which was not due to maturation did not occur until after 9 days of age. In experiment 2, separate groups of mice received 25 escape training trials at either 8 or 10 days of age, and were retested 24 hrs later. Comparisons of the retest scores with original training scores as well as with littermate controls without prior training experience, showed that 8‐day old mice failed to show retention effects of prior training, whereas 10‐day old mice performed better on the retention test than they had on original training, as well as better than controls without previous training. The results suggest that 24‐hr memory of the escape task develops at 9–10 days of age in the C3H mouse.
Prenatal exposure to an ELF‐rotating magnetic field and subsequent increase in conditioned suppression
Authors: Persinger Michael A. , Pear Joseph J.
Published: January 2005

Male rats were exposed prenatally to a .5 Hz, .5–3 to 10–30 gauss rotating magnetic field (RMF), comparable in frequency (but of slightly higher magnitude) to extreme low frequency magnetic fields associated with some geomagnetic and meteorological disturbances. In three replications, RMF‐exposed rats showed significantly greater suppression in response rate (relative to controls) during the 4‐min conditioned stimulus (CS) preceding a .5 mA, .5 sec shock in a conditioned suppression procedure. The RMF‐exposed animals showed the greatest suppression, relative to controls, during the first few shock exposures. Subsequent CS‐shock pairings were followed by similar suppression in both groups. RMF‐exposed rats also showed more initial suppression during the first presentation of the CS without shock. These findings are consistent with previous open field and Sidman avoidance data that suggest that the RMF‐exposed animals are more reactive to novel and aversive stimuli, and underline the importance of understanding the effects of everyday geophysical‐meteorological variables upon development and consequent behavioral changes.
Distress vocalizations of young in three inbred strains of mice
Authors: Nitschke Werner , Bell Robert W. , Zachman Thomas
Published: January 2005

Vocalizations of young mice of 3 inbred strains, C57BL/6J, BALB/cJ, and C3H/HeJ, were recorded at 3, 6, 9, 12, 15, and 18 days of age. Recordings were made at ambient room temperature (23.5° ± 1.5°C) or under conditions of reduced temperature (2° ± 2°C). Strains differed in terms of rate of signaling, peak frequencies of signals, and average signal duration. Peak frequencies appear to be genetically coded, and did not vary with age or ambient temperature. The effects of reduced ambient temperature on C3H/HeJ and BALB/cJ pups were to extend the age span during which frequent signaling occurs, and to increase the average signal duration throughout that age span. The C57BL/6J pups emitted fewer signals under reduced temperature, but also showed an increase in signal duration.

Strain differences in age functions of signaling and the differential impact of experience on the various parameters of the vocalizations suggest that these vocalizations may be a useful behavior in monitoring genetic‐experiental interactions and developmental rates in young mice.
Postnatal experience and the detection of the effects of prenatal stress on behavior: A reply to archer and blackman
Authors: Joffe J. M.
Published: January 2005

In the course of a recent review of the effects of prenatal stress on offspring behavior, Archer and Blackman (1971) advanced some suggestions concerning the effects of the age of the offspring and their postnatal experience on the detection of prenatal stress effects. Specifically, they felt that studies they reviewed indicated that the behavioral effects of prenatal stress wane as offspring grow older and that “previous test experience (involving a mild or severe stress situation) causes the response to persist, enabling it to be detected in tests carried out when the animals are older”.
The ontogeny of the onset of drinking and plasma osmotic pressure regulation
Authors: Almli C. Robert
Published: January 2005

Pertinent behavioral and physiological variables related to the development of the onset of drinking were measured in albino rats of both sexes between 14 and 100 days of age. Under ad libitum conditions all variables studied were found to increase as a function of age. Following a subcutaneous 16% NaCl injection mean latency to drink was found to range from 4.6‐9.5 min across ages. Plasma osmolality levels at the initiation of drinking were found to increase as a function of age and were found to be elevated over ad libitum levels by a relatively constant magnitude. The onset of drinking across ages was associated with 2.8‐6.6% increase in plasma osmolality. These data suggest that although absolute levels of ad libitum osmolality increase from birth to maturity, the threshold increase in osmolality required for the initiation of drinking remains quite constant.
Absence of behavioral deficits following neonatal undernutrition in the rat
Authors: Slob A. Koos , Snow Catherine E. , de Natris‐Mathot Els
Published: January 2005

Previous studies of the effects of early undernutrition on behavior in adult rats have confounded underfeeding with maternal deprivation or membership in a large litter. In the present experiment food‐deprived rats received full‐time maternal care and lived in the same‐sized litters as well‐fed controls. In contrast to previous findings food‐deprived animals in the present study did not differ from controls in the open‐field test, in a test of motor coordination, and in 2 learning tasks. However, food‐deprived animals were more active than controls in a residential plus maze. Females showed less effect of food deprivation on body growth, but a much greater effect on activity, than males. These findings suggest that early undernutrition when not confounded with social and maternal deprivation may have more restricted effects on adult behavior than has been previously believed.
Motor behaviors of neonatal rhesus monkeys: Measurement techniques and early development
Authors: Castell Rolf , Sackett Gene
Published: January 2005

Development of newborn monkeys was assessed by 2 techniques. The 1st was a film analysis measuring aspects of walking, climbing, and jumping in mother‐reared infants. The 2nd used a “Baby‐Spin” apparatus consisting of a cloth covered bag which rotated in the vertical plane through 360°, 2 sec spins. Mother‐reared monkeys walked and climbed on Week 1 but did not jump until Week 3. The duration of arm and leg movements was constant, but because distance of movements changed the speed of limb movement increased over Weeks 1–5. Clasping and grasping responses were in synchrony from the first week of life. Clasping pressure to initial acceleration increased over the first 3 weeks, with greatest pressures at head‐down angles on Weeks 1 and 2, and a double‐peaked function, appearing on Weeks 3 and 4 with pressure maxima at both head‐down and head‐up angles. Developmental changes in clasping could be seen in longitudinal or cross‐sectional comparisons, or in comparisons confounded by effects of prior test experience.
The effects of litter size and post‐weaning isolation or grouping on adult emotionality in C3H mice
Authors: Priestnall Robin
Published: January 2005

Eighty‐three C3H mice were reared in litters of 2 or 8 pups until weaning and, thereafter, in isolation or in bisexual groups of 8‐10 animals in a Litter Size × Postweaning Experience × Sex factorial design. At 70‐75 days of age, subjects were tested in a modified version of the open‐field test, designed to overcome some of the reported difficulties in using the conventional test with mice. Animals reared in small litters obtained significantly higher scores than animals reared in large litters on 3 measures of exploratory behavior, though no differences were observed in defecation, eating, and grooming in the arena. Subjects isolated after weaning showed significantly more exploratory behavior and significantly less grooming, eating, and defecation in the test situation than animals kept in groups; males obtained significantly lower scores on 2 of the measures of exploratory behavior and on grooming than females. In general, the pattern of behavior shown by animals reared in larger litters, by animals grouped at weaning, and by males, is taken as indicating a higher level of emotionality.
Responses to electrical stimulation of the median nerve in the human newborn
Authors: Ellis Ron R. , Ellingson Robert J.
Published: January 2005

Four normal full‐term newborns and 4 adults were stimulated by constant‐current square‐wave pulses to the median nerve at the wrist. Thumb and finger movement thresholds were determined by visual observation and by recording movement potentials from the thenar eminence. Afferent nerve action potential thresholds were determined by recording from the median nerve above the elbow. Subjective sensory thresholds were also determined by verbal report in the adults. Somesthetic evoked responses (SEP) were recorded from the contralateral scalp at movement threshold and 2 times the movement threshold in both infants and adults. The mean afferent nerve action potential threshold of the newborns was 3 times higher than that of the adults. The mean movement thresholds of newborns and adults were not significantly different. The mean action potential threshold was not different from the mean subjective sensory threshold in the adults. The mean action potential threshold was not different from the mean movement threshold in the newborns. Shocks of movement threshold intensity are not always adequate for elicitation of afferent action potentials and SEP's in newborns. In stimulating peripheral nerves to elicit SEP's, the positions of the stimulating electrodes are critical.
Spontaneous and testosterone‐induced pup killing in female Rockland‐Swiss mice: The effect of lactation and the presence of young
Authors: Gandelman Ronald , Davis Paula G.
Published: January 2005

Cannibalism of pups by adult, virgin, Rockland‐Swiss mice did not occur during the lactation period following the subsequent pregnancy of these animals. However, upon retesting 2 weeks after the weaning of their young, 5 of 13 again killed pups. Testosterone propionate was ineffective in eliciting pup killing when administered during the lactation period. The continuation of androgen treatment for 1 week after weaning did lead to the cannibalism of 1‐day old foster young. Finally, testosterone administration did not induce pup killing in spontaneously maternal virgin female mice when pups were constantly present.
Transcallosal and transhippocampal evoked potentials in developing guinea pig brain
Authors: Savarie Peter J. , Hosko Michael J.
Published: January 2005

Transcallosal and transhippocampal evoked responses were studied in the guinea pig from 50 days of fetal life to adulthood. Variations in the time of appearance and in response latency of these 2 evoked potentials were observed during maturation. In 50‐day fetuses transcallosal responses could not be elicited; however, transhippocampal responses were present. In newborn animals, latency of transhippocampal responses was the same as that observed in adults, whereas latency of transcallosal responses was 3‐4 times longer than the adult response.
Sleep state periodicity in prematures and young infants
Authors: Stern Evelyn , Parmelee Arthur H. , Harris Margaret A.
Published: January 2005

An autocorrelation technique was used to determine the periodicity underlying successive recurrences of specific sleep states (Quiet Sleep and Active Sleep). Groups of short (2–3 hr) polygraphic records and individual all‐night recordings were analyzed. Active Sleep and Quiet Sleep periodicities at 32 weeks conceptional age were 12 min. At 36 weeks, 40 weeks (term), and 1, 3, and 8 months, the periodicity of both Active and Quiet Sleep was consistently in the 40–60 min range. At all ages, the cycle time of one state was consistently longer than the other. The appearance of clear periodicities underlying both states and the similarity of the periodicities found in 36 week records to those found in much older infants' records indicate that this biological rhythm is basic to human CNS functioning. The Index of Rhythmicity values in these records and other investigators' data suggest that this rhythm reaches a mature form by 36 weeks postconception.
Effect of anesthesia and/or hypothermia on cerebral free amino acids in young rats
Authors: Sarajas H. S. S. , Oja S. S.
Published: January 2005

The whole brain content of glutamic acid significantly decreased in unanesthetized and anesthetized (pentobarbital sodium. 20 mg/kg) 10‐day‐old rats during 90 min hypothermia at 23°C, but not in rats kept equally long at 15°C. The concentration of glutamic acid increased during rewarming to 37°C after 90 min at 23 or 15°C. The concentration of aspartic acid significantly increased during rewarming after 90 min at 23 or 15°C. Rats anesthetized for 10 or 90 min at 37°C had increased cerebral concentrations of leucine and methionine, but the concentrations were significantly lower in rats kept for 90 min at 23°C. During rewarming after 90 min at 23 or 15°C the levels of leucine and methionine increased. The content of ethanolamine phosphate was significantly elevated in rats kept anesthetized for 90 min at 37, 23, or 15°C. An elevated ethanolamine phosphate concentration was found also in unanesthetized rats kept for 90 min at 15°C. Only minor alterations were found in the concentrations of glutamine, glutathione, γ‐aminobutyric acid, taurine, alanine, ethanolamine, glycine, and serine.
Infantile stimulation and exploratory behavior in the rat
Authors: Williams D. I.
Published: January 2005

Rats were handled (H) or left non‐handled (NH) prior to weaning. They were tested at approximately 35 days of age for 3 min/day, on 3 consecutive days, in a Y‐maze having 1 black/white striped arm and 2 gray arms. Ambulation scores were significantly lower for NH animals which showed a greater preference for the striped arm as measured in terms of initial choice and time spent in that arm. The inference is that here NH animals exhibit a greater tendency to explore than H animals; the opposite conclusion would have pertained if ambulation had been used as the sole measure of exploration.
Postnatal development of the electrocortical activity in the golden hamster (Mesocricetus auratus)
Authors: Callison David A. , Himwich Williamina A. , Turner John K.
Published: January 2005

Electrical activity was recorded from the occipital and parietal cortices of the golden hamster at the ages of 1, 2, 5, 7, 10, 13, 15, 20, 25, 30, 45, days, and adult (1 yr). Additional animlas were used for determination of brain weight and for studies of neuronal development. In the golden hamster the ECoG activity appeared by Postnatal Day 2 as intermittent and slightly irregular low voltage activity. From 7 to 10 days the amount of fast activity (18 ‐ 20 cps) increased as did the amplitude in the slow waves of 6 – 9 cps. By 15 days the ECoG pattern was essentially similar to that the adult hamster. However, an augmentation in voltage and a predominance of faster rhythms (18 ‐ 25 cps) were observed as the animal matured. Neurohistological data revealed that the cortex approached the general anatomical pattern of the adult by the 13th to 15th postnatal day.
Reinstatement of early experiences and later learning: An animal analogue for human development
Authors: Wachs Theodore D.
Published: January 2005

Previous research has indicated a relative impermanence of early experience effects when humans are used as subjects. As suggested earlier, the concept of reinstatement, as developed by Campbell, might be a useful one for understanding this pattern of findings. Unfortunately, previous studies of reinstatement have utilized specific early experiences, as opposed to the nonspecific early experiences received by human infants. The present project was an attempt, using rats, to determine if the reinstatement paradigm is valid when nonspecific experiences were utilized. The results indicate that the reinstatement of nonspecific experiences enhances later learning as effectively as the reinstatement of specific experiences.
The relevance of memory, arousal, and cue factors to developmental changes in spontaneous alternation by rats
Authors: Egger Garry J.
Published: January 2005

Three studies are reported which indicate that memory factors, heightened arousal, and differences in the use of cues are not responsible for the differences in spontaneous alternation (SA) behavior which have been typically found to exist between infant and adult rats. Experiment I examined memory as a factor by reducing intertrial intervals to a minimum. This manipulation did not alter alternation rates at any of the ages studied. Experiment II investigated the effect on alternation of reducing the heightened arousal of young rats by the use of the nonspecific depressant drug chlorpromazine hydrochloride. Alternation rates in both infant and adult rats were again unaffected. Experiment III indicated that 16‐day old rats are influenced by the same spatial and olfactory cues that evoke SA in mature animals, but that they tend to use these in a different fashion to adults. The results supported the hypothesis that inhibitory deficiencies in young animals are responsible for the typical perserverative pattern of choices made by these animals in an equal alternative 2‐choice T‐maze situation.
Growth and behavior of surrogate‐reared squirrel monkeys
Authors: Kaplan Joel
Published: January 2005

Infant squirrel monkeys of the Colombian and Peruvian varieties were reared on surrogates until they were 24 weeks old. The weights of the Colombian animals were consistently greater than those of the Peruvian animals, and the males of each type were heavier than the respective females. The behavior of both groups was similar in most respects and much like that reported for surrogate‐reared rhesus infants. However, the Colombian infants did spend less time than the Peruvians on the surrogate during the first 12 weeks, and none of the animals exhibited anything resembling the stereotyped body‐rocking that has been described for the surrogate‐reared rhesus.
Olfactory recognition in the infant squirrel monkey
Authors: Kaplan Joel , Russell Michael
Published: January 2005

Infant squirrel monkeys were reared with surrogates and tested at 4, 8, and 12 weeks of age on their preferences for odors and colors of the surrogates. Surrogates in the rearing color that contained an infant's own odor were preferred to clean ones of the same color. Surrogates in the rearing color that did not contain an animal's scent were generally not preferred to different colored surrogates that were also clean. The results suggest that olfaction plays an important role in the development of social attachment in the young squirrel monkey and is more effective than at least one source of visual information.
Seizure susceptibility and avoidance conditioning in adult rats treated prenatally with chlorpromazine
Authors: Golub Mari , Kornetsky Conan
Published: January 2005

Offspring of female rats treated early in gestation with chlorpromazine (CPZ) were tested at 30 days of age for seizure susceptibility and at 90 days of age for shock avoidance learning. Fostering procedures permitted separation of prenatal influences from postnatal rearing influences of drug treatment. Offspring of drug‐treated mothers had higher avoidance scores, higher intertrial activity levels, and greater seizure susceptibility than offspring of controls. Animals reared by previously treated mothers also had higher avoidance and greater seizure susceptibility. This postnatal effect depended on sex and was not accompanied by an overall increase in intertrial activity. Rearing by a previously drug‐treated mother was also found to modify the influence of neonatal stress on adult avoidance learning.
Development of early behaviors in neonatal squirrel monkeys and cotton‐top tamarins
Authors: King James E. , Fobes Jacqueline T. , Fobes James L.
Published: January 2005

The development of simple, nonsocial behaviors was observed in neonatal squirrel monkeys and cotton‐top tamarins. One group of observed behaviors included rooting, orienting up, clasping, and grasping, and was assumed to be more directly related to maintenance of maternal contact and nursing than others such as visual and auditory orienting, crawling, walking, and climbing down. Comparison of the results with previously reported data from rhesus monkeys and galagos supported the hypothesis that neonatal behaviors related to maternal contact and nursing persist longer in species with relatively passive maternal behaviors than in species with relatively active maternal behaviors. In contrast, the development of neonatal behaviors not directly related to maternal contact and nursing was not found to vary reliably as a function of species.
Adult‐litter relations in rats reared in single and dual‐chambered cages
Authors: Plaut S. Michael
Published: January 2005

BLU:(LE) rats were reared in cages which allowed movement of adults, but not pups, between 2 chambers. Some were reared in cages containing a virgin female (aunt) in addition to the mother. Although prenatal preferences for location and food and water consumption were for the side on which the litter was eventually delivered and reared, most postnatal food and water consumption occurred on the nonlitter side. Adult‐litter contact decreased from 90% of Day 1 to 40% of Day 21, decreasing more rapidly during the dark hours. Presence of aunts increased activity of mothers, but did not affect adult‐litter contact. Pups in the dual cages displayed higher rates of solid food consumption at age 17 days and lower brain weights at 21 days than pups in single cages.
Habituation in the neonatal rat
Authors: File Sandra E. , Plotkin H. C.
Published: January 2005

Habituation of a head‐raising and turning response elicited by a puff of air directed at the dorsal body surface was investigated in neonatal rats over the first 7 days postpartum. The procedures used provided controls for litter effects, spontaneous activity, body temperature loss, sensitization effects, and handling. From Day 3 the response could be elicited significantly more frequently than it occurred spontaneously. Thereafter, on each successive day, the animals required an increasing number of trials to habituate this response.
Septal damage during the maturation of inhibitory responding: Effects in juvenile and adult rats
Authors: Schoenfeld Thomas A. , Hamilton Leonard W. , Gandelman Ronald
Published: January 2005

Septal lesions were inflicted in young rats either during or after the maturation of inhibitory responding. When tested as juveniles (Day 25) or as adults, septal‐operates were significantly different from controls on 2‐way active avoidance and habituation responding, regardless of the age at which the lesion was produced. These data are in contrast with others showing that damage to subcortical structures can result in sparing of certain behavioral functions. The difference between functional sparing and functional disruption may be due to different patterns of brain projection pathways established after early lesions are produced. Neurochemical supersensitivity may also be a differentiating factor.