bluuebunny/crossref_metadata_2025 huggingface dataset:
Stereochemical and biochemical aspects of organoboron(III) compounds of hydrazonecarboxamides and hydrazonecarbothioamides
Authors: Saxena Chitra , Singh R. V.
Published: January 2005

Hydrazonecarboxamides and hydrazonecarbothioamides and their derivatives have important pharmacodynamic significance. In the search for better fungicides and bactericides, organoboron(III) compounds derived from these ligands were screened for their antifungal and antibacterial activities. The heterocyclic aldimines were prepared by the condensation of (2‐furanyl)methanal, (2‐thienyl)methanal, (2‐pyridinyl)methanal, (1H‐indol‐3‐yl)methanal or 3‐phenyl‐2‐propenal with hydrazinecarboxamide or hydrazine‐carbothioamide. Unimolar and bimolar reactions between phenyldihydroxyborane and these ligands have produced PhB(OH)(NO), PhB(NO)2, PhB(OH)(NS) and PhB(NS)2 types of biologically active compounds. Structural assignment has been made through UV, IR and NMR (1H, 11B and 13C) spectroscopy. TGA and XRD of a representative compounds have also been carried out. The compounds were tested in vitro against a number of fungal and bacterial strains and were found to possess moderate to good toxicity.
The fate of mercury species injected into coelomic fluid of starfish Leptasterias polaris
Authors: Maheu Sophie , Pelletier Emilien
Published: January 2005

Mature starfish Leptasterias polaris, collected in the St Lawrence Estuary (eastern Canada), were exposed to two mercury species (HgCI2 and CH3HgCI) via injections into the coelomic fluid. In vivo effects of some complexing agents (glutathione, mercaptoethanol and EDTA) on the distribution of 203Hg‐labelled species in starfish organs and tissues and their possible role in mercury transport through membranes were studied over a 24 h period. The excretion of ammonia and mercury was also measured. When injected alone, inorganic mercury and methylmercury [CH3Hg(II)] were distributed in all organs, with a preferential adsorption in gonads, pyloric caeca and stomach. Mercury excretion was very low under all conditions studied. Mercaptoethanol, a small thiol ligand, was very efficient in reducing both mercury species in the coelomic fluid and seems to have promoted translocation towards most organs of the starfish. Its action is attributed to the formation of small and neutral complexes, HgL2 and CH3HgL, which can diffuse through membranes preserving their integrity. Glutathione increased the translocation of CH3Hg(II) towards surrounding organs, but had no apparent effect on inorganic mercury. EDTA promoted the transport of inorganic mercury only. These results highlight (1) the particular interest of starfish to workers studying in vivo chemical complexation of mercury species, and (2) the potential role of complexing molecules in the biotransport of mercury species through living membranes.
Catalytic properties of metal‐containing polymethylsiloxanes
Authors: Fiedorow R. , Przystajko W. , Adamiec J.
Published: January 2005

Aluminium‐, iron‐, titanium‐ and zirconiumcontaining polymethylsiloxanes were studied as catalysts for acid‐catalysed reactions; their surface acidity and the strengths of their acid centres were determined. They appeared to be active for 2‐propanol dehydration; the best sample was almost as active as alumina, which is known for its high activity for alcohol dehydration. All metalcontaining polymethylsiloxanes (MPS) catalysed double‐bond migration and cis‐trans isomerization of 2‐butene. Some of them also catalysed the synthesis of methyl t‐butyl ether, but their activity for this reaction was inferior to that of the resin Amberlyst‐15 and some of sulphate‐ion modified metal oxides. No cumene conversion occurred on the catalysts studied and no pyridinium ion formation was observed by IR spectroscopy, which points to the absence of strong Brönsted acid sites. The MPS are distinguished by quite large surface areas (86‐299 m−2g−1) and are capable of chemisorbing pyridine (0.014‐0.047 mmolg−1) on their Lewis acid centres.
Optimization of fast atom bombardment (FAB) mass spectra of arsenobetaine and arsenocholine
Authors: Florêncio M. H. , Duarte M. F. , Bettencourt A.
Published: January 2005

Optimized FAB mass spectra of arsenobetaine and arsenocholine may be obtained when the matrices glycerol and thioglycerol are used.
Dictionary of organometallic compounds, B. J. Aylett, M. F. Lappert and P. L. Pauson (eds) Chapman and Hall, London £2950 (hardback). £3500 CD ROM (single user). $8750 CD ROM (network). ISBN 0 412 43060 6 (five‐volume set)
Authors: Craig P. J.
Published: January 2005

No Absract.
Behaviorally induced changes in length of cerebrum in rats
Authors: Altman Joseph , Wallace Robert B. , Anderson William J. , Das Gopal D.
Published: January 2005

In normal rats, growth in the width of the cerebral hemispheres ceases about 21 days of age, but growth in length continues at a reduced, steady rate in the young‐adult. Three behavioral treatments were used to determine whether this late phase in cerebral growth is sensitive to environmental influences. Rats that were trained on a complex visual discrimination task for 4 months had significantly longer cerebral hemispheres than their passive littermates. Rats that were raised in enriched or social environments had longer cerebral hemispheres than rats raised in isolation. Finally, the cerebrum of unhandled rats was shorter than that of rats handled during infancy; that of the latter was shorter than the cerebrum of trained or enriched animals. No changes were observed under any of these conditions in cerebral width. These results indicate that the length of the cerebrum characteristic of normal rats does not represent a genetically determined, fixed level. This level is not attained under certain rearing conditions and it can be surpassed when the complexity of the environment is increased. The morphological bases of these changes were not determined.
Rabbit eyelid conditioning: Effects of age, interstimulus interval, and intertrial interval
Authors: Frey Peter W. , Ross Leonard E.
Published: January 2005

Young rabbits (5–7 weeks old) conditioned more rapidly and demonstrated longer latency responses than older rabbits (14–20 weeks old) with an 800‐msec interstimulus interval. With a 200‐ or 400‐msec interval, conditioning rate and response latency were similar for both age groups. Although a 4‐min intertrial interval produced conditioning in fewer trials than a 1‐min interval, there was no interaction of this variable with the age factor.
Effects of differential environments on brain weights and enzyme activities in gerbils, rats, and mice
Authors: Rosenzweig Mark R. , Bennett Edward L.
Published: January 2005

In 2 experiments, littermate male gerbils were kept in enriched (EC), standard colony (SC), or impoverished (IC) environments from 30 to 60 days of age. Cerebral effects of these environmental treatments were compared with results obtained previously with laboratory rats and mice. The EC gerbils show, in comparsion with IC, an increase in cortical weight and an increase in the cortical/subcortical weight ratio, a decrease in cortical acetylcholinesterase per unit of weight, and a slight increase in the ratio of cholinesterase to acetylcholinesterase in the cortex. These changes for the most part follow the pattern of EC‐IC effects found in the rat and mouse. In both absolute brain measures and in EC‐IC effects, the gerbil resembles the rat more closely than the mouse. The results extend the generality of findings within Rodentia from the family Muridae, which includes rats and mice, to the family Cricetidae, to which gerbils belong. Furthermore, the gerbil, unlike the laboratory rat and mouse, has not been subjected to many years of selection for laboratory conditions.
Estimation of catecholamines in the brains of embryonic and newly hatched chickens and the effects of reserpine
Authors: Sparber S. B. , Shideman F. E.
Published: January 2005

Reserpine significantly decreased the concentrations of atecholamines (CA) in the brains of 14‐ and 18‐day‐old chicken embryos when administered prior to incubation in a dose that has little or no effect upon hatchability. Administration of this drug had profound effects upon the fluorometric estimation of CA in the brains of both embryonic and newly hatched chicks. This can lead to an erroneous interpretation of the quantitative effects of reserpine on CA concentrations in the brain.
Effects of auditory stimulation on heart rate in premature infants as a function of level of arousal, probability of CNS damage, and conceptional age
Authors: Schulman Carol A.
Published: January 2005

In 2 experiments, heart rate responses of newborn infants to an auditory stimulus as a function of sleep vs wakefulness, probability of perinatal impairment of the central nervous system, and developmental level were compared. All subjects were studied under standard conditions, in their own incubators, using an 80 dB (re 0.02 dynes/cm2) low‐frequency buzzer of 3‐sec duration. Heart rate responses were averaged over 10 trials for each subject in each state. In the first study, which compared the responses of high‐ and low‐risk subjects of 1800 gm or greater weight, it was found that there was no difference between the groups in the response during sleep; or greater weight, it was found that there was no difference between the groups in the response during sleep; during wakefulness, however, a significant difference in the direction of response was found. High‐risk subjects accelerated, as in sleep, whereas low‐risk subjects decelerated. In a developmental study of 4 small premature infants, it was found that the direction of the waking heart rate response changed from acceleration to deceleration at about 35 to 36 weeks conceptional age.
Studies of undernutrition in the young rat: Methodological considerations
Authors: Plaut S. Michael
Published: January 2005

Three techniques are generally described as creating a state of undernutrition in the young rat: large litter size, periodic mother‐litter separation, and early weaning. Evidence from studies of maternal behavior and early experience suggests that many of the effects seen in „nutritional deprivation”︁ experiments may be due, in part, to the social, thermal and sensory deprivation coincident with maternal deprivation, or to other factors (such as handling) which are often confounded with maternal deprivation. These other variables must be systematically accounted for before assumptions can be made about the effects of undernutrition per se.
Infantile stimulation and ultrasonic signaling: A possible mediator of early handling phenomena
Authors: Bell Robert W. , Nitschke Werner , Gorry Thomas H. , Zachman Thomas A.
Published: January 2005

Peromyscus maniculatus bairdi were either handled or not handled daily during the first 10 days of life. Handling consisted of removing the infant mice from the litter, placing them in small individual compartments where they remained for 3 min, and then replacing them in the nest. Immediately following the handling, simultaneous video and audio recordings were made of nest behavior for two 30‐sec recording sessions. The nonhandled controls were treated comparably except that pups were never removed from the nest. Handled litters differed from nonhandled in terms of the average number of signals per recording session (132.5 vs. 16.5), the average signal duration (0.108 sec vs. 0.045 sec), and the average peak frequency of signals (22.216 kHz vs. 11.990 kHz). During those recording sessions in which no vocalizations were detected no physical interaction appeared between the mother and the infants. During all sessions in which vocalizations were emitted the mother was retrieving and grooming the infants. The data suggest a possible interpretation of the effects of early handling in terms of modified mothering, medidiated by modified vocalizations of infant mice as a function of the handling.
Senile web patterns in Uloborus diversus (Araneae: Uloboridae)
Authors: Eberhard William G.
Published: January 2005

Elderly females of the spider Uloborus diversus (Uloboridae) spin webs which are different in various respects than those spun earlier in their lives. “Senile” virgins' webs differed from those of “senile” non‐virgins' in several characteristics and in some ways resembled those of first instar nymphs.
Reinforcement value of electrical brain stimulation in neonatal dogs
Authors: Bacon W. Edward , Wong Ira G.
Published: January 2005

Electrical brain stimulation in puppies during the first week of life was correlated with crawling from a demonstrably preferred to nonpreferred tactual stimulus. Preferences changed when the structures stimulated were the same as reward areas in adult mammals, thus demonstrating that electrical stimulation in the infant brain has positive reinforcement value.
Mirror self‐image reactions before age two
Authors: Amsterdam Beulah
Published: January 2005

The behavior of 88 children between 3 and 24 months was observed before a mirror, using an objective technique to examine the child's awareness of the image as his own. The results indicate the following age‐related sequence of behavior before the mirror: the first prolonged and repeated reaction of an infant to his mirror image is that of a sociable “playmate” from about 6 through 12 months of age. In the second year of life wariness and withdrawal appeared; self‐admiring and embarrassed behavior accompanied those avoidance behaviors starting at 14 months, and was shown by 75% of the subjects after 20 months of age. During the last part of the second year of life, from 20 to 24 months of age, 65% of the subjects demonstrated recognition of their mirror images.
Environmentally induced changes in the dimensions of the rat cerebrum: A replication and extension
Authors: Walsh Roger N. , Cummins Robert A. , Budtz‐Olsen Otto E.
Published: January 2005

In previous reports exposure to 80 or 90 days of environmental complexity induced a significant increase in the length of the rat cerebrum, whereas 30 days' exposure induced changes which failed to reach significant levels. In the present study after 30 days of differential rearing, cerebral length was 1.2% (p < .005) greater in brains from the enriched animals; the region contributing to this increase lay between the anterior pole and the point of greatest cerebral width. Measurements of cerebral width and brain weight failed to show any significant change, but the body and adrenal weights of the isolated rats were 19.9% (p ≤ .02) greater, respectively, than those of their littermates reared in environmental complexity. However, the ratios of adrenal weight to body weight did not differ significantly between groups.
Pacifier‐produced visual buffering in human infants
Authors: Bruner Jerome S.
Published: January 2005

Non‐nutritive sucking in human infants aged 9–13 weeks produces buffering by reducing visual scanning movements in the presence of movement‐invoking cinematic visual displays of both representational and abstract types. Scanning is correlated with movement in a display without the presence of sucking to buffer it.
An investigation of various egg‐opening techniques for use in avian behavioral embryology
Authors: Oppenheim Ronald W. , Levin Hinda L. , Harth Marshall S.
Published: January 2005

The effects of various egg‐opening techniques, including the Kuo Vaseline technique, upon survival, hatchability, and embryonic behavior have been experimentally evaluated in the present study. The major aim was to develop a technique that could be used for long term behavioral studies throughout most of incubation. The Kuo Vaseline technique was found to provide the poorest results in terms of survival and hatchability: none of the embryos in eggs opened by this technique hatched. Two techniques, however, did provide adequate survival and hatchability such that they could easily be used for behavioral observation of the chick embryo from the 2nd day of incubation until hatching. These latter techniques involved partial removal of the inner shell membrane in the air‐space; or the placement of a lateral window over the embryo along the side of the egg. Of all the techniques evaluated only the Vaseline technique resulted in a significant modification of the embryos' movements.
Hypothyroidism and the maturation of the hypothalamo‐hypophyseal‐adrenal axis
Authors: Meserve Lee A. , Leathem James H.
Published: January 2005

Rats were made hypothyroid by feeding .25% thiouracil in a semipurified casein diet to mothers from the first day of pregnancy through lactation. At 15 days of age, concentrations of adrenal and serum corticosterone were comparable in euthyroid and hypothyroid young, suggesting a basal ACTH release. Ether stress, however, failed to elicit an increased synthesis and release of corticosterone in the hypothyroid rat, but was effective in the euthyroid animal. Exogenous ACTH, on the other hand, did induce corticosterone synthesis and release in hypothyroid and euthyroid rats, indicating a functional adrenal gland. Thus, neonatal hypothyroidism appears to influence the hypothalamus. The retarded maturation of this axis may play a role in behavioral deficiencies seen in hypothyroid animals.
Mother‐infant separation in squirrel monkeys living in a group
Authors: Jones Byron C. , Clark Dennis L.
Published: January 2005

Two female and 3 male infant squirrel monkeys were separated from their mothers at a mean age of 169 days. All had been group reared. The experiment entailed three 5 day periods: (1) preseparation; (2) separation; and (3) reunion. During the experiment, each infant was observed for 10 min per day. Frequency and duration measures were recorded for activity play, locomotion, object manipulation, and disturbance. Social behaviors recorded were contact play, mixed play, competition play, sex play, affiliation, display, and aggression.

Changes noted during separation were depression of activity play, contact play, mixed play, object manipulation, and sex play. Affiliative behaviors and locomotion increased during separation.

After reunion, locomotion and affiliation returned to baseline levels while contact play, mixed play, and object manipulation remained depressed.
Brain weight changes resulting from enriched rearing conditions: A diallel analysis
Authors: Henderson Norman D.
Published: January 2005

Housemice from 6 inbred lines and their F1 crosses were reared in standard or enriched laboratory cages. A genetic analysis of brain and body weights indicated a significant directional dominance effect toward larger brain in F1 crosses among enriched animals only, even when adjustments for body weight were made. The proportion of additive genetic variance was greater in standard caged animals than in enriched animals. Maternal effects played a small but significant role in influencing brain weights apart from those indirectly caused by body weight effects. The use of laboratory reared animals for genetic studies is questioned when environmental influences are known to have a strong effect on the character being studied, and the results are to be used to make inferences concerning the adaptive significance of the character.
Straight‐alley escape behavior in infant mice: Effect of shock intensity
Authors: Nagy Z. Michael , Misanin James R.
Published: January 2005

Separate groups of Swiss‐Webster mice between 5‐15 days of age received 25 training trials in a straight‐alley escape task at 1 of 4 shock intensities, ranging from .1‐.8 mA. An increase in shock level led to better escape performance at all ages, although the amount of improvement varied directly as a function of age. The results supported earlier work suggesting that the competing response measure was the most useful index of improved escape behavior at the early ages. Running speeds did not indicate improved within‐session escape performance at any age or shock level, although speeds clearly reflected maturational and motivational differences between groups.
Novelty induced changes in spontaneous alternation by infant and adult rats
Authors: Egger Garry J.
Published: January 2005

Previously, preweaned rats have been shown to perseverate rather than alternate choices of goal arms over 2 trials in a T‐maze. In this study 16‐day old animals were successfully induced to increase their rate of alternation to chance level in the present experiment by increasing the novelty value on Trial 2 of the previously unchosen goal arm. Similarly, 100‐day old rats were encouraged to decrease their level of alternation by enhancing the novelty value of the previously chosen arm. An explanation for these findings was offered in terms of the escitatory and inhibitory effects of a stimulus, and the gradual development of inhibition in ontogeny.
Maternal vitamin A excess during the early fetal period: Effects on learning and development in the offspring
Authors: Hutchings Donald E. , Gibbon John , Kaufman Mavis A.
Published: January 2005

Pregnant rats were administered a teratogenic dose of vitamin A excess on Days 14 and 15 of gestation. Intubation controls received the vehicle alone; nontreated mothers were not disturbed; all groups were fostered to untreated mothers after birth. Treated offspring showed a generalized retardation in growth as evidenced by delayed onset of fur growth, eye‐opening, and reduced body weight. Treated subjects acquired the operant S+, S− discrimination during adulthood significantly slower than the controls because of a failure to inhibit responding in S−. Although their proportion of S+ responding eventually reached the level of the controls, they failed to acquire comparably long S− latencies, even during 40 sessions when S− responding was punished with shock. The treated rats evidently were less able to inhibit responding in the signal which indicated nonreinforcement. Histological examination of the brains revealed that the maternal vitamin A excess produced an overall reduction in offspring brain size with obvious microcephaly occurring in 1 animal.
The effects of premature delivery on subsequent development of the rat
Authors: Grota Lee J. , Ambruso Dan
Published: January 2005

Delivery of rat fetuses 18 hr prematurely results initially in decreased body weight and delayed development of the negative geotropic response compared to full‐term infants. At adulthood, prematurely delivered rat fetuses were less emotional than full‐term controls, but did not differ in weight, learning, and susceptibility to gastric erosions.
Effect of genotype and practice upon behavioral development in mice
Authors: Fuller John L. , Herman Barbara H.
Published: January 2005

Psychomotor development from birth to 18 days of age was observed in 3 lines of mice selected for high (H), medium (M), and low (L) brain weight. Litters were cut to 8 at birth and half of the individuals randomly assigned to a practiced group tested daily; the remainder were assigned to a nonpracticed group and were tested only on selected tests on the day at which their littermates met a predesignated criterion. Significant differences between the lines were found in open field activity, balancing on a rotorod, age of eye‐opening, and edge avoidance. The H‐line was generally more advanced than either M or L. On some measures, righting for example, no strain variation was found. The effects of practice were usually significant, but did not abolish strain differences.

Most research on the behavioral effects of genetic variation in the nervous system has been concerned with effects of mutant genes producing major disruption of developmental patterns. Our results indicate that genes affecting the rate and amount of normal brain growth also influence behavioral development. Genes of this type may be responsible for some of the individuality of behavioral phenotype found in natural populations.
Mirror image and self‐recognition in young human infants: I. A new method of experimental analysis
Authors: Papoušek Hanuš , Papoušek Mechthild
Published: January 2005

The infant's responses to his mirror image have been viewed as indices of self'recognition, but a lack of experimental evidence has caused contradictory conclusions on the beginning of self'recognition. The authors suggest that infants may respond to several factors in the mirror image: eye'to'eye contact, contingency of the image on their own behavior, a smiling face, another babyish being or another human being in general, and the identity of the image with their concept of self. A method for the study of these factors is described. The mirror image was replaced with a televised self‐image which was presented simultaneously with another matching image in a 2‐choice preference design. The discriminant variables between both images equate individual factors of the mirror image in individual modifications of the method. In this pilot study of eleven 5‐month‐old infants, the basic methodological questions were solved, and the first attempt was made to evaluate the roles of eye‐to‐eye contact and of mirror‐image contingency.
Escape learning: Acquisition and extinction rates as a function of age in rats
Authors: Egger Garry J.
Published: January 2005

An asymptotic measure of acquisition incorporating both escape latencies and competing responses (180° turns away from the goal box) was used to compare escape learning over ages in rats. Rats aged 24, 50, and 100 days did not differ in the number of trials required to reach acquisition as determined by this criterion. However, the youngest group required significantly more trials than either of the older groups to extinguish responding in this situation. They also performed significantly more competing responses than the older group in the early stages of acquisition.
Ovarian influences on the development of sexual behavior in neonatally androgenized rats
Authors: Hendricks Shelton E. , Duffy John A.
Published: January 2005

Female sexual behavior was studied in male and female rats. Males were castrated on the day of birth (Day 1); some received ovarian implants at that time; others were injected on Day 3 with oil, 5 μg testosterone propionate (TP), or 50 μg TP. Females were ovariectomized at birth, 20, or 60 days of age; on Day 3 all were injected with oil, 5 μg, TP, or 50 μg TP. Prepuberal ovarian tenancy in females tended to counteract the effects on sexual receptivity of TP administered during neonatal life. In males ovarian implants facilitated female sexual behavior at adulthood in oil‐injected animals, but did not significantly influence the effect on neonatally injected TP.
Infant development in two prosimian species: Greater galago and slow loris
Authors: Ehrlich Annette
Published: January 2005

Infant development in 2 prosimian species‐‐greater galago and slow loris‐‐was studied in 2 ways. First, the initial appearance and/or the eventual disappearance of various simple motor behaviors in infants was recorded. Second, the time spent by mothers and infants in contact, near, and away from each other was measured during the first 10 weeks of life. The aim was to see how the 2 sets of measures relate to each other and also to compare the 2 prosimian species with each other and with other primates. The results showed that: (1) contrary to the views advanced by some authors, the speed with which simple motor behaviors attain the adult form is not related in any consistent way to phyletic status, age at which sexual maturity is reached, or the mother's ability to provide manual support for her infant; (2) the pattern of mother‐infant interaction is more variable in prosimian than in anthropoid primates; and (3) the disappearance of involuntary foot‐grasping coincides with the initiatior of infant independence from the mother.
Critical periods in the organization of systems
Authors: Scott J. P. , Stewart John M. , De Ghett Victor J.
Published: January 2005

The general theory of critical periods applies to organizational processes involved in the development of any living system on any level of organization and states that the time during which an organizational process is proceeding most rapidly is the time when the process may most easily be altered or modified. Complex organizational processes involving 2 or more interdependent subprocesses may show 1 to several critical periods, depending on the time relationships of the subprocesses. The nature of the relationships between interdependent processes operating on different levels is again dependent on time and is a more meaningful formulation than that of the old “innate‐acquired” dichotomy. These theoretical considerations lead to the conclusion that understanding a critical‐period phenomenon rests on analyzing the nature of the organizational process or processes involved. An example is given in a review of research on the critical period for primary socialization (social attachment) in the dog. Evidence that attachment has taken place consists of discriminative behavior in relation to familiar and unfamiliar objects and rests on a minimum of 3 processes: (1) organization of the separation distress response; (2) visual and auditory sensory capacities; and (3) long‐term associative memory capacities. Once these capacities are developed, the overall attachment process proceeds very rapidly (the critical period for such attachment). Thus the critical periods for the organizational subprocesses precede or slightly overlap that for the overall process. Deeper analyses of these processes must rest on neurophysiological research. The theory of critical periods is a general one that should apply to any developmental organizational process which proceeds at grossly different rates at different times.
Following and visual imprinting in ducklings across a wide age range
Authors: Brown Robert T.
Published: January 2005

Ducklings ranging in age from 20–125 hr were exposed to a moving silent object in an open circular apparatus until a criterion of 300 sec of following was met. All duckings met the criterion, and age did not correlate with the time required. In subsequent choice tests most ducklings approached the imprinting object over a novel object, and age did not correlate with choice behavior. Results indicate that imprinting can occur over a fairly wide age range, and that the traditional critical period for imprinting may, in part, be an artifact of laboratory methods.
Impairment of conditioned active avoidance in adult rats given corticosterone in infancy
Authors: Olton David S. , Johnson Craig T. , Howard Evelyn
Published: January 2005

Intensive corticosterone treatment given to rats during the 1st postnatal week irreversibly decreases DNA accumulation in the cerebrum and cerebellum. After such hypercorticism in infancy rats were tested as adults in 2 conditioned active avoidance tasks. In comparison with litter‐mate controls, the treated rats were impaired in the acquisition of 2‐way active avoidance but not in the acquisition of 1‐way active avoidance. These data are consistent with other observations suggesting a hyperresponsiveness or hyperemotionality following corticosterone treatment in infancy.
Developmental changes in pre‐adult behavior in confined colonies of golden hamsters
Authors: Goldman L. , Swanson Heidi H.
Published: January 2005

Eight litters of hamsters living in a large enclosure were observed from birth to 120 days. For the first 65 days each litter was confined to a separate compartment. Basic motor coordination was reached by the 3rd week. Marking was seen during the 6th week when males began to mount their mothers sexually, but lordosis was not seen in female pups before the 7th week. Fighting appeared at this time with the females being the more aggressive.

At 65 days the litters were combined into 2 groups of 4. A gradual shift followed in the relative aggressiveness of the sexes. Females, which had previously initiated over 90% of attacks, became less aggressive, whereas attacks by males increased to the former female level. This unusual behavior for hamsters, where females are normally dominant, may have been due to crowding. Also, severe disruption of maternal behavior occurred with marked infanticidal tendencies.
Olfactory bulbectomy and nursing behavior in rat pups (Wistar DAB)
Authors: Singh Pauline Jirik , Tobach Ethel
Published: January 2005

To determine whether bilateral olfactory bulbectomy led to a change in nursing behavior, and thus death, we bilaterally bulbectomized (BX) pups from 14 litters at 2, 7, and 11 days of age. Litters treated on Days 2 and 7 consisted of 3 BX pups, 2 surgical control (SC) pups, and 2 handling control (HC) pups. Litters treated on Day 11 consisted of 1 or 2 BX, 1 or 2 incompletely bulbectomized pups (IBX), 2 SC pups, and 2 HC pups. These litters and 3 additional nontreated litters were observed on Days 4, 7, 10, 13, and 16. A smaller number of BX pups survived through Day 10 than SC, HC, IBX, and nontreated pups. Differential treatment of the BX pups by females or littermates was not found. The females' mammary glands were functional but the BX pup stomachs had little or no milk. The BX pups spent less time nursing and more time away from the female and their littermates than did the other pups.
Handling rabbits in infancy: In search of a critical period
Authors: Wyly Mary Virginia , Denenberg Victor H. , De Santis Darlene , Burns Joan Kennedy , Zarrow M. X.
Published: January 2005

In Experiment 1 rabbits were handled for the first 10 days of life while controls were not disturbed. In Experiment 2 rabbits were handled on Days 11–20. In Experiment 3 rabbits were handled on Days 1–10, 11–20, 1–20, or were not handled. Starting at 31 days the animals were given an open‐field test, a test for exploratory behavior toward novel stimuli, and a test of social behavior. The data were not consistent with the critical period concept. Instead, handling during the first and second 10‐day intervals appears to be additive and to approximate the effects of 20 days of handling.
Acute versus chronic acoustic deprivation: Effects on auditory evoked potentials and seizures in mice
Authors: McGinn Michael D. , Henry Kenneth R.
Published: January 2005

C57BL/6J mice are not typically susceptible to audiogenic seizures, but temporary conductive hearing loss (via earplugging) can induce susceptibility in these subjects. The present study observed that a 40‐dB hearing loss, beginning at 17 days postpartum, requires 2 days before it induces susceptibility to audiogenic seizures. When this hearing loss occurred only between 17 and 21 days postpartum, seizures were maximally severe 1–2 days after earplug removal. The peak‐to‐peak amplitudes of the auditory evoked potential (AEP) were also maximal at this same time. But mice deprived of acoustic input between ages 42–46 days exhibited equally large or even larger AEP amplitudes, while not exhibiting susceptibility to audiogenic seizures. Animals at this older age were shown to be capable of convulsing, in that chronic conductive loss from 17–42 days maintained susceptibility to audiogenic seizures. The acoustic deprivation produced both behavioral (audiogenic seizures) and neural (augmented AEP amplitudes) supersensitivity to sound, but the former requires a critical period, whereas the latter does not. Some degree of residual hearing loss persisted at all ages for approximately 2 days after removal of the earplugs.
Prenatal maternal d‐amphetamine effects on emotionality and audiogenic seizure susceptibility of rat offspring
Authors: Seliger Deborah Levy
Published: January 2005

Dosages of 0, 5, and 10 mg/kg body weight of d‐amphetamine were injected subcutaneously to gravid albino rats during Days 5–9 or Days 12–16 of gestation. Offspring were assessed for water‐wading emotionality and audiogenic‐seizure behaviors. No significant differences among groups were found in defecation scores from either test. The only animals to exhibit a considerable incidence of wild‐running attacks or seizures were these whose mothers had received the placebo early in pregnancy. These differences are in agreement with most findings that indicate an enhancement of immunity to audiogenic seizure susceptibility as a function of prior stress. Maternal administration of d‐amphetamine during pregnancy apparently can produce offspring who have less susceptibility to severe emotional responses but no protection against mild expressions of emotionality.
Defensive distance and immobility in young precocial birds (Gallus gallus)
Authors: Ginsburg Harvey J.
Published: January 2005

The manifestation and duration of the tonic immobility reaction in 3‐day‐old chicks (Gallus gallus) was found to vary reliably as a function of the spatial proximity between the hand of the experimenter and the immobilized chick. The results of this experiment indicate that young birds are susceptible to immobility and that the maintenance of close spatial proximity is the condition necessary for the occurrence of the reaction in young precocial birds.
Voluntary exposure to light by young and aged albino and pigmented inbred mice as a function of light intensity
Authors: Wax Teena M. , Goodrick Charles L.
Published: January 2005

Young (5 month) and old mice (23 and 26 months) of the inbred A/J and C57BL/6J strains (N = 80) were isolated in ventilation chambers with ad lib food and water for 1 week at a time. Each animal was allowed to select its own lighting schedule by pressing one lever to turn on a light of either 10.76 or 166.40 lux illumination intensity and pressing another lever to turn the light off. Three‐way analyses of variance for Age, Strain, and Illumination effects on parameters of bar pressing, stimulus change, and light duration patterns per circadian period (24 hr) indicate that old mice are less active than young mice and the A/J mice are less active than C57BL/6J mice. Young mice spent more time in the dark than old mice and the A/J albino mice spent more time in the dark than did the C57BL/6J pigmented mice. Other age and strain differences were noted as well and are discussed with respect to some theories of light exposure by nocturnal animals.
Effects of age and genotype on acquisition of an active avoidance response in mice
Authors: Stavnes Karen , Sprott Richard L.
Published: January 2005

Two experiments were conducted in which inbred C57BL/6J and DBA/2J mice were trained in an active avoidance jump‐up task under distributed practice conditions at a variety of ages comprising a large part of their life‐span. DBA/2J mice were found to be basically an escaping strain and exhibited little change in behavior as a function of age. C57BL/6J mice developed consistent avoidance behavior when training was initiated at 31–36 days of age. Avoidance behavior appeared to reach a peak in the 45–day‐old group and progressively decreased in 145‐ and 560‐day‐old groups. Increased footshock intensity in old DBA/2J mice enhanced escape responding without increasing avoidance responding. Increased footshock intensity in old C57BL/6J mice enhanced avoidance responding.
The development and modification of object preferences in domestic white leghorn chicks
Authors: Einsiedel Albert A.
Published: January 2005

This study examined in domestic chicks the time‐course of adaptation to a new object after having established strong preferences for a previous stimulus (during the first 3 days of life). By interchanging the stimuli to which the animal was exposed, and by confining the animal exclusively with the new object for some period of time, the new preference was expected to develop as a function of the duration of exposure. The results confirm that expectation with a monotonic increase in preference as a function of hours of exposure. The establishment of a preference for the new object was rapid, as indicated by a significant shift in preference after 5 hr.
Daylength and sexual maturation in female house mice
Authors: Drickamer Lee C.
Published: January 2005

A series of 4 experiments investigated the relationship between daylength and sexual maturation in female house mice. Mice reared in constant light matured significantly later than mice maintained under photoperiods involving 0, 6, 12, or 18 hr of light/day. Results of an experiment involving cross‐classified combinations of pre‐ and postweaning photoperiods revealed that only the postweaning photoperiod treatment was a significant factor influencing the attainment of puberty. Studies of body growth, food consumption, and wheel‐running activity in young females housed under different photoperiods indicated that mice kept in constant light grew more slowly during the first 10 days after weaning, generally consumed more food than mice at other photoperiod conditions, and failed to exhibit regular daily activity patterns like those of mice maintained under photoperiods of 0 or 12 hr of Night/day. Constant illumination apparently disrupts the normal physiological and behavioral activity rhythms and delays the attainment of sexual maturity.
Developmental patterns of seizure susceptibility in inbred strains of mice
Authors: Deckard Betty S. , Lieff B. , Schlesinger K. , Defries J. C.
Published: January 2005

Samples of mice from each of 6 inbred strains were tested for audiogenic and electroconvulsive seizures at 5 ages (14, 21, 28, 35, and 42 days). A moderately large within‐strain correlation (.67) was found, indicating that developmental patterns of susceptibility to audiogenic and electroconvulsive seizures are similar within each strain. The finding of an even larger between‐strain correlation (.91) indicated that strains which are highly susceptible to audiogenic seizures are also likely to be highly susceptible to electroconvulsive seizures.

In a 2nd experiment, whole brain norepinephrine and serotonin were assayed in each of 5 inbred strains at 21 and 42 days of age. Results were consistent with the hypothesis that levels of these amines are inversely related to seizure susceptibility. Mice from strains which were susceptible to seizures at 21 days of age had significantly lower levels of norepinephrine and serotonin in brain than did 42‐day‐old, seizure‐resistant animals.
Absence of effects of corticosterone given at 22 days
Authors: Howard Evelyn
Published: January 2005

Mice given a single large dose of corticosterone at 2 days of age, and tested when adult, have shown lasting alterations in operant behavior, associated with reductions in cerebral weight and DNA content. When mice were given corticosterone at 22 days, no changes appeared in cerebral weight, DNA, or in operant behavior, but an apparent decrease did occur in open‐field activity. The results suggest that the effects of corticosterone treatment at 2 days on the developing brain are mediated by one or more types of sensitivity to the steroid that have been largely lost by 22 days.
Rapid changes in cerebral blood flow and initial visual experience in the developing chick
Authors: Bondy Stephen C. , Purdy Janet L.
Published: January 2005

A single eye of young chicks was sewed shut for various times. Regions contralateral to and primarily or secondarily innervated by the sutured eye had a reduced rate of cerebral blood flow in comparison to the corresponding ipsilateral regions. However, upon reopening the sutured eye after 2 days, these contralateral regions (optic lobes and cerebral hemispheres) exhibited a rapid increase in cerebral blood flow to a level significantly above that in control ipsilateral areas. The duration of this effect was considerably prolonged in chicks that were monocularly sutured immediately after hatching without prior exposure to light. Chicks that had 1 week of normal vision before monocular suture did not show this overcompensatory effect. If the period of monocular suture was extended to 7 days before restoration of vision to the occluded eye, the overcompensatory vascular effect was delayed. The maximal effect was apparent only upon the 1st exposure of an eye to major visual input. A possible relation exists between this rapid increase in regional blood flow and the period when visual imprinting could normally be expected to be maximal.
Peculiarities in the changes of catecholamine level in the brain, blood, and adrenals of dogs and rats in ontogenesis
Authors: Rozanova V. D. , Khodorova N. A.
Published: January 2005

The norepinephrine content of the whole brainstem and of its differnt parts and the epinephrine and norepinephrine (NE) content in the blood and adrenals in dogs and rats during ontogenesis were studied.

The catecholamine (CA) level in the blood and different parts of the dog brainstem increased to the age of 20‐30 days and then decreased. The NE value of the whole dog brainstem increased to the age of 9‐30 days, and then decreased. The content of NE of the rat brainstem increased to the age of 120 days and then decreased. The amount of CA of the dog and rat adrenals increased progressively from birth to adulthood. The CA brain and adrenal level of dogs during postnatal ontogenesis was lower than in rats.
The organization of sleep and wakefulness after maternal separation in young rats
Authors: Hofer Myron A.
Published: January 2005

Two‐week‐old infant rats were studied before and after 24 hr of maternal absence. This experience produced an increase in time spent awake, a reduction in time spent in paradoxical sleep (PS), and an increased frequency of state transitions with more frequent and shorter periods of both slow‐wave sleep (SWS) and PS. Body movements were increased and nonnutritive sucking decreased during PS after separation. Other aspects of sleep organization were relatively stable: the pattern of probability of direction of state transitions, the integration of the physiological and behavioral determinants of state, the pattern and amount of nonnutritive sucking, and the underlying PS cycle period. These findings, and the results of 2 control experiments, suggest that some aspects of the prolonged absence of the mother produce a shift in the infant'apos;s central neutral state regulation through processes yet to be understood.
The behavioral effects of prenatal hypoxia in the rat
Authors: McCullough Maurice L. , Blackman Derek E.
Published: January 2005

Pregnant rats were exposed to an oxygen depleted atmosphere (13% oxygen in nitrogen) at normal pressure in 2‐hr daily sessions extending over approximately the last 14 days of pregnancy. Their progeny were compared with control progeny in terms of age of eye‐opening, open‐field behavior, and Hebb‐Williams maze problem solving ability. The groups were not distinguishable by their performance in the open‐field, but the experimental animals opened their eyes significantly earlier and made significantly more errors on Hebb‐Williams maze problems.
Motor reactions during the antenatal period correlated with the periodic change in the activity of the cardiovascular system
Authors: Arshavsky I. A. , Arshavskaya E. I. , Praznikov V. P.
Published: January 2005

A connection between the periodic appearance of vagal bradycardia and of intrauterine large‐amplitude respiratory movements, as well as the appearance of generalized jerky‐type and more sustained extensor motor reactions, has been established in experiments on dog fetuses connected with the mother through the umbilical cord. Brief vagal bradycardia also arises immediately after completion of these reactions and is an analogue of the vagal phase in adults after motor activity. These correlated phenomena are caused by periodic reversible mild hypoxemia which through the chemoreceptors of the sinocarotid zone stimulates the centers of vagal innervation of the heart and the centers of innervation of skeletal muscles. These phenomena disappear when the mother inhales a gas mixture containing less than 14‐15% oxygen or greater than 50‐60% oxygen, as well as when the mother is under deep anesthesia.