bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dopamine antagonists produce an age‐dependent increase in the responding of the young chick
Authors: Zolman James F. , McDougall Sanders A. 
Published: January 2005

AbstractIn three experiments the effects of dopamine receptor antagonists on response‐contingent punishment and autoshape learning of 1‐ and 4‐day‐old chicks were determined. In the first two experiments, 1‐ or 4‐day‐old chicks (N = 120) were trained to key‐peck for heat reward and then injected intraperitoneally (ip) with either haloperidol (1.5, 2.5, or 5.0 mg/kg) or saline (Experiment 1) and with either haloperidol (2.0 mg/kg), sulpiride (50 mg/kg) or saline (Experiment 2) 30 min before a 96‐trial response contingent punishment session. In Experiment 3, 1‐ and 4‐day‐old chicks (N = 48) were injected ip with saline or haloperidol (2.0 mg/kg) 30 min prior to a 30‐trial autoshape learning session. In both the punishment and appetitive tasks 1‐day‐old chicks pretreated with either haloperidol (1.5 to 2.5 mg/kg) or sulpiride showed a significant increase in key‐peck responding compared with their saline injected controls. In contrast, 4‐day‐old chicks given either haloperidol (2.0 mg/kg) or sulpiride did not differ significantly from saline treated chicks on the punishment task, and on the autoshape task haloperidoltreated 4‐day‐old chicks responded on fewer trials than did their saline controls. These results indicate that dopaminergic synaptic transmission in the young chick as measured by dopamine D2 receptor blockers is functionally different at 1 compared with 4 days of age.
The effect of early experience on water maze spatial learning and memory in rats
Authors: Tees Richard C. , Buhrmann Kristin , Hanley Jordan 
Published: January 2005

AbstractIn the first of two experiments on spatial competence, groups of light‐reared (LR) and dark‐reared (DR) rats were compared using a (latent learning) variation of the Morris Water Maze task. On their initial test, the LR rats benefited more than DR rats did from viewing the room/pool from a platform in the correct location. Further, visually experienced rats remember the location of the platform more than DR rats when retested one month later. In a second experiment, in which a proximal cue as well as location was varied from trial to trial, LR rats again proved to be more competent than their DR counterparts. This second task also revealed significant benefits related to stimulation history in the case of a third group of animals raised in enriched or complex environment (CR) conditions. The results are discussed in terms of the nature of the impact of early experience on the ability to acquire and remember spatial concepts.
Kinematic variability and relationships characterizing the development of walking
Authors: Lasko‐McCarthey Peggy , Beuter Anne , Biden Edmund 
Published: January 2005

AbstractThe purposes of this study were: (1) to determine the pattern of variability and relationships in joint kinematics characterizing the development of walking and (2) to determine whether controlling for postural stability in new walkers results in less variability. The variability and relationships among hip, knee, and ankle motions were measured during 10 gait cycles of new walkers, supported new walkers, two‐year‐olds and seven‐year‐olds. Fourier series were generated for each joint motion and standard deviations were compared across groups. An age‐related decline in variability was evident in select portions of the cycle. Stance and swing phase duration correlated with cycle duration for all ages. Postural support did not lessen variability in joint rotations for new walkers. Cross‐correlations for hip‐knee, knee‐ankle, and hip‐knee rotations were strong across all groups. These results suggest that a coordinative structure for walking produces strong intralimb coupling early in development, despite variability in select portions of joint motions.
Developmental constraints on the expression of behavioral and heart‐rate orienting responses: I. The role of cardiosomatic coupling
Authors: Hayne Harlene , Richardson Rick , Campbell Byron A. 
Published: January 2005

AbstractThe ontogeny of behavioral and heart‐rate orienting responses to a novel olfactory stimulus was examined in three experiments. The results of Experiment 1 demonstrated that behavioral responses to the olfactory stimulus were observed as early as early as Day 1, although heart‐rate deceleration in response to the stimulus was not observed until Day 9. In Experiment 2, bradycardia was observed in 6‐day‐old pups if stimulus‐elicited motor activity was reduced with haloperidol. Thus, the developmental asynchrony in the expression of behavioral and heart‐rate orienting responses was due, at least in part, to cardiosomatic coupling in the very young animal. The results of Experiment 3 demonstrated that although cardiosomatic coupling interferes with the expression of the heart‐rate orienting response very early in development, it has increasingly less impact over the course of the preweaning period.
A refractory period for the heart rate response in infant visual attention
Authors: Casey Betty Jo , Richards John E. 
Published: January 2005

AbstractA refractory period for the heart rate (HR) response of 14‐, 20‐, and 26‐week‐old infants to second stimulus onset and primary stimulus offset during termination of visual attention was investigated. A stimulus that elicited a significant HR deceleration was presented. Following the return of HR to prestimulus level, a second stimulus occurred or the first stimulus ended at time delays of 0, 3, 6, and 9 s. If the second stimulus occurred at 0 or 3 s after HR returned to its prestimulus level, the HR response was smaller than the initial HR orienting response (OR). A usual HR OR resulted by waiting 6–9 s after the return of HR to prestimulus level. A significant offset response occurred only for the 6‐sec delay. Active inhibition of vagal cardiac activity during attention termination may cause the observed refractory period in the HR response, which appears to last from 3–6 s following sustained attention.
Time course of the effect of maternal deprivation on the hypothalamic‐pituitary‐adrenal axis in the infant rat
Authors: Levine Seymour , Huchton David M. , Wiener Sandra G. , Rosenfeld Patricia 
Published: January 2005

AbstractProloged (i.e., 24‐hr) maternal deprivation leads to a marked disinhibition of the infant rat's adrenocortical response to stress and/or ACTH. In the following study we examined the time course over which these effects develop. Pups were maternally deprived for varying lengths of time (i.e., 0, 2, 4, 8, & 24 hr); at the end of this period, corticosterone (CORT) secretion in response to stress (novelty or novelty plus saline injection) and ACTH injection was measured. Basal levels of CORT increased progressively over time in 7‐and 11‐(but not 3‐) day‐old pups. CORT release in response to stress followed a similar pattern. In contrast, ACTH injection resulted in marked increases in CORT levels regardless of the length of maternal deprivation in 3‐day‐old animals; at older ages, however, 24 hr of deprivation led to a much larger increase. These findings support the hypothesis that the hypothalamic‐pituitary‐adrenal axis of the neonatal rat is subject to maternal regulation.
The biphasic effect of morphine on odor conditioning in neonatal rats
Authors: Randall Christopher K. , Kraemer Philipp J. , Dose John M. , Carbary Timothy J. , Bardo Michael T. 
Published: January 2005

AbstractThree experiments examined the dose‐dependent biphasic effect of morphine on odor conditioning in neonatal rats. In Experiment 1, a single pairing of an odor and a low dose of morphine (0.5 mg/kg) in 5‐day‐old rats produced an odor preference, relative to an unpaired control group. In Experiment 2, pairing an odor with a high dose of morphine (2.0 mg/kg) produced an odor aversion, relative to an unpaired control group. A third experiment compared performance of a group given odor and morphine (2.0 mg/kg) paired to that of two unpaired groups: one given morphine 24 hr prior to and the other 24 hr after odor exposure. The paired group showed an odor aversion relative to both of the unpaired groups, which did not differ. The latter finding suggests that even if morphine metabolism is incomplete after 24 hr, behavior is unaffected. These results are discussed in reference to the functional development of the opioid system in rats © 1992 John Wiley & Sons, Inc.
Developmental thermoregulatory deficits in prenatal ethanol exposed long‐ and short‐sleep mice
Authors: Gilliam David M. , Kotch Lori E. 
Published: January 2005

AbstractSensitivity to alcohol may influence the severity of prenatal alcohol effects. To examine this hypothesis, the ontogeny of thermoregulation was measured in prenatal ethanol exposed offspring of mice selected for differences in alcohol sensitivity. Pregnant long‐sleep (LS) and short‐sleep (SS) mice were exposed to 3 or 4 g/kg ethanol or an isocaloric amount of maltose‐dextrin twice per day from day 7 through 18 of pregnancy. Doses were given six hours apart via gavage. Nonintubated lab chow controls were included for both genotypes. Offspring were fostered at birth to lactating mice of an outbred strain. Offspring temperatures were measured at 0, 60, and 120 min away from the nest on alternating days from 7 through 21 days of age. LS and SS offspring prenatally exposed to the high ethanol dose showed lower temperatures at the 60 and 120 min time points on each day of testing compared to all other treatment groups. Temperatures of offspring prenatally exposed to the low ethanol dose did not differ from controls. These results suggest a relatively steep dose‐response curve for thermoregulatory deficits in LS and SS offspring prenatally exposed to alcohol. Genetically‐based alcohol sensitivity did not influence the effects of prenatal alcohol exposure on this response © 1992 John Wiley & Sons, Inc.
Visual discrimination and recognition of facial expressions of anger, fear, and surprise in 4‐ to 6‐month‐old infants
Authors: Serrano Juan M. , Iglesias Jaime , Loeches Angela 
Published: January 2005

AbstractOn the assumption that the ability to discriminate facial expressions has adaptive value to infants during early social exchanges, ethologically based theorists have argued that this ability is innate. Guided by this perspective, we investigated the ability of infants, 4–6 months old to recognized and discriminate facial expressions of anger, fear, and surprise. Results obtained with an infant‐controlled habituation‐recovery procedure showed that infants both discriminated and recognized these expressions when portrayed by several adult female models. In addition, infants spent more time looking at expressions of anger and surprise that at fear expressions. These results suggest that infants can abstract configurations of features that give affective meaning to facial expression. It is suggested that the differences in habituation to each expression might be the result of their distinct functional signification for the infant. © 1992 Wiley & sons. Inc.
The ontogeny of phencyclidine‐induced wall climbing and locomotor activity
Authors: Scalzo Frank M. , Burge Lora J. 
Published: January 2005

AbstractWall climbing behavior is an age‐specific behavior that is elicited during postnatal Days 7 through 17 by various stimuli that include heat, odors, shock, and the catecholaminergic agonists apomorphine, amphetamine, and clonidine. In a previous study, a significant amount of wall climbing behavior was observed during ataxia and activity testing following phencyclidine (PCP) administration in Day 19 but not Day 40 rat pups. The present study describes the ontogeny of PCP‐induced wall climbing behavior and locomotor activity. Frequency and duration of wall climbing bouts and locomotor activity were recorded on Days 5, 12, 19, 26, 33, or 40 following PCP treatment. On Day 12, all doses of PCP induced significant amounts of wall climbing behavior. A similar pattern of results was observed on Day 5 although these effects were not statistically significant. After Day 12, PCP‐induced wall climbing behavior declined precipitously. PCP increased locomotor activity at all ages tested with maximum activities observed on Day 19. These results demonstrate that PCP‐elicited wall climbing behavior follows an ontogenetic profile similar to that previously reported for other stimuli and that there are robust ontogenetic differences in the locomotor response to PCP. © 1992 Wiley & sons. Inc.
Social and nutritional influences on the feeding of ring dove squab
Authors: Iskrant Katharine R. , Balsam Peter D 
Published: January 2005

AbstractThe effects of food deprivation on ring dove squabs′ begging and pecking was examined during the period of transition from dependent to independent feeding. Food‐deprived squabs begged more, pecked more, and were fed more by their parents than nondeprived squabs. When deprived, young squab primarily beg for food and older squab primarily peck. This difference may arise from the relative efficiencies of the two feeding responses at different ages. Additionally, parental state exerted control over the amount the squab pecked and begged. Parental food deprivation affected squab pecking, probably because hungry parents pecked more themselves and fed squabs less. Squab begging was not affected by parental food deprivation. However, parental separation from squab affected squab begging, as parents previously without squab were more likely to feed begging squab than were parents who were not separated from squab. Parental separation from squab did not affect squab pecking. The changes in the endogenous and exogenous controls of squab feeding allow for a great deal of plasticity in the transition from dependent to independent feeding.© 1994 John Wiley & Sons, Inc.
Behavioral profiles of adult rats in a difficult food supply social situation, related to certain early behavioral features
Authors: Deviterne Dominique , Peignot Patricia , Krafft Bertrand 
Published: January 2005

AbstractBehavioral profiles of male rats were defined in nine intralitter groups of six individuals at various stages of their development: (a) at pup stage in individual situations (uncomfortable positions) and social situations (removal away from the mother), and (b) at adult stage in a difficult food supply social situation (complete immersion of the food access way). The male population was split into two sets, both at pup stage (the most and the least swift and efficient of each group to overcome uncomfortable situations), and at adult stage (carriers and noncarriers of food in each group tested). Our results showed an important relation between these pup and adult behavioral profiles: the swiftest and most efficient individuals of a group at pup stage adopted more often a food carrier behavioral profile at adult stage. Assumptions about the predictive value of some behavioral features of a young rat in regard to its adult behavioral profile are discussed.© 1994 John Wiley & Sons, Inc.
State evaluation in a legislative environment: Adapting evaluation to legislative needs
Authors: Brown Judith R. 
Published: January 2005

AbstractState legislatures began recognizing evaluation as an important aspect of their oversight responsibilities in the late sixties. Since that time, evaluation has become an integral part of the legislative process. This chapter delineates such key issues as how the Illinois Office of the Auditor General has addressed legislative evaluation and the challenges and dilemmas evaluators must address to enhance their future effectiveness.
Plasticity of astroglia: Evidence supporting process elongation by “stretch”
Authors: Jaeger Christine B. 
Published: January 2005

AbstractThe structural plasticity of cerebral astroglia was investigated in vivo by implantation experiments. Immunocytochemical markers for glia filament protein were used to identify the astrocytes. First it was established that implanted nitrocellulose filters provided a substrate for astrocytes from different brain regions of young rats. Astrocytes attached to the filter and projected fine processes into it. Longer implantation times increased the density and length of glial processes within filter spaces. Astrocytes that penetrated the filters implanted in the tectum exhibited more processes than those in the cortex, suggesting regional differences of astrocyte distributions. Second it was observed that astrocyted that attached to the filter formed elongated processes when they were tethered within an expanding matrix. This was shown by implanting the nitrocellulose filter together with PC12 cells that continued to grow. The implantation of neither PC12 cells without filters nor nitrocellulose filters alone induced the formation of elongated astroglia with parallel aligned processes, resembling radial glia. Such glial forms only occurred in the filter/PC12 cell cografts. This indicates that processes of astrocytes adherent to nitrocellulose filters could be stretched in response to expansion of the surrounding tissue.
Cytotopographical specialization of enzymatically isolated rabbit retinal Müller (glial) cells: K+ conductivity of the cell membrane
Authors: Reichenbach Andreas , Eberhardt Wolfgang 
Published: January 2005

AbstractMüller (radial glial) cells were isolated from rabbit retinae by means of papaine and mechanical dissociation. Regional membrane properties of these cells were studied by intracellular microelectrode recordings of potential responses to local application of high K+ solutions. When different parts of the cell membrane were exposed to high K+, the amplitude of the depolarizing responses varied greatly, indicating a strong regional specialization of the membrane properties. Using morphometrical data of isolated rabbit Müller cells, and a simple circuit model, we calculated the endfoot membrane to constitute more than 80% of the total K+ conductance of the cell; the specific resistivity of the endfoot membrane was about 400 Ωcm2, i.e., more than 40 times less than that of the membrane of the vitread process, which is immediately adjacent. This kind of regional membrane specialization seems to be optimized in respect to the Müller cells+ ability to carry spatial buffering K+ currents.
Schwann cell myelination of the myelin deficient rat spinal cord following X‐irradiation
Authors: Duncan I. D. , Hammang J. P. , Gilmore S. A. 
Published: January 2005

AbstractThe myelin‐deficient (md) rat is an X‐linked myelin mutant that has an abnormality of oligodendrocytes and a severe paucity of myelin throughout the CNS. This lack of myelin makes it an ideal model in which to study the cellular interactions that occur when “foreign” myelinating cells are induced in the milieu of this nonmyelinated CNS. In this study, Schwann cells were induced in the lumbosacral spinal cord by exposing it to radiation, a technique demonstrated repeatedly in other nonmutant strains of rats. Md rats and their age‐matched littermates were irradiated (3,000 to 4,000 R) at 3 days of age and perfused 16–22 days later after pulse labeling with tritiated thymidine. In the md rat, Schwann cell invasion progressed from the area of the spinal cord–nerve root junction and extended into the dorsal columns and adjacent gray matter. Autoradiographic evidence revealed that many of these cells incorporated 3H‐thymidine, indicating that they were undergoing proliferation. Ultrastructural observations showed that there was an integration of these intraspinal Schwann cells with the cells normally occurring in this environment, i.e., oligodendrocytes and astrocytes. The extent of migration and division of Schwann cells, as well as their interactions with glial cells, were similar to those seen in the nonmutant irradiated littermates. These studies provide conclusive evidence that md rat axons are normal with respect to their ability to provide trophic and mitogenic signals to myelinating cells.
Cytoplasmic membrane elaborations in oligodendrocytes during myelination of spinal motoneuron axons
Authors: Waxman S. G. , Sims T. J. , Gilmore S. A. 
Published: January 2005

AbstractThe ultrastructure of paranodal oligodendroglial cytoplasm, which is located in proximity to the forming myelin sheath, was studied during maturation of spinal motoneuron axons in rat. At 8 days postnatal, the paranodal oligodendroglial loops contain a network of membrane‐bound tubulovesicular elements. These membrane elaborations are most common in oligodendroglial loops attached to the outermost layers of the myelin sheath, i.e., paranodal loops closest to the nodal gap. The number of oligodendroglial cytoplasmic profiles per paranodal loop falls over the course of five to ten sequential paranodal loops, and these profiles are nearly absent in paranodal oligodendroglial cytoplasm located distant from the nodal gap. Oligodendrocytes in spinal cords of 14‐ and 20‐day‐old rats and of adult rats did not exhibit networks of tubulovesicular profiles. The appearance of these membrane organelles within oligodendroglial cytoplasm during myelin maturation suggests increased membrane turnover within paranodal cytoplasm located adjacent to the axon that is being myelinated. Membrane turnover within oligodendrocytes may reflect axonal modulation of glial function during myelination.
Prenatal gliogenesis in the developing cerebrum of the mouse
Authors: Choi Ben H. 
Published: January 2005

AbstractA correlative light microscopic, ultrastructural, and immunocytochemical study was made of the brains of C57BL/6J mice obtained between embryonic day (E‐) 11 to postnatal day (P‐) 3. The deployment of radially oriented glial cells within the neopallium was already apparent by E‐12, at which time the expanded endfeet of processes abutting the basement membrane at the pial surface showed ultrastructural evidence of glial differentiaon. Scattered, horizontally arranged glial cells were also observed within the marginal zone prior to the arrival of the cortical plate neurons. Indirect immunofluorescence for glial fibrillary acidic protein (GFAP) was detected at the outer margins of the neopallium at E‐12, antedating the expression of GFAP in radially organized fibers. Radial fibers traversing the full thickness of the neopallium became strongly immunoreactive for GFAP only at and after day E‐16. These findings provide evidence of early gliogenesis in the developing mouse forebrain and indicate that GFAP is as readily demonstrable in mouse astrocytes and radial glial fibers as it is in those of man and subhuman primates.
Patterns of glial proliferation during formation of olfactory glomeruli in an insect
Authors: Oland Lynne A. , Tolbert Leslie P. 
Published: January 2005

AbstractParitioning of the first‐order olfactory neuropil into glomeruli in the developing brain of the moth Manduca sexta occurs only in the presence of olfactory sensory axons and appears to be mediated by changes in glial cells (Oland et al.: J. Neurosci., 8:353–367, 1988). The arrival of sensory axons in the brain triggers changes in glial shape and position that lead to the formation of a glial scaffolding for the developing glomeruli. The presence of mitotic figures in glial cells at stages before glomeruli emerge (Oland and Tolbert: J. Comp. Neurol., 255:196–207, 1987) suggested that glial proliferation might also contribute to the formation of the glomerular envelopes. To determine whether glial proliferation is induced by olfactory axons, we have used 3H‐thymidine to label dividing cells before, during, and after the formation of glomeruli and have compared the patterns of proliferation in normal and chronically unafferented olfactory neuropils. We found significant differences in mitotic indices only after glomerular walls had been established, indicating that the sensory axons induce the formation of glomerular envelopes primarily via the changes in glial morphology and distribution, not by stimulating glial proliferation.