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This study was prompted by reports of functionally normal humans with micrencephaly or cortical hypoplasia. Methylazoxymethanol acetate (MAM) treatment, which induces micrencephaly in rats, was administered by injection (20 mg/kg) on Gestational Day 14. Prior to weaning and into adulthood, offspring were assessed on many behavioral tests. There were 3 findings. First, MAM rats (forebrain weight less than two-thirds of controls) were not profoundly hyperactive. Increased activity was seen only on prolonged tests or after amphetamine administration. Second, MAM rats were hypoactive in some conditions. These rats were light shy and less likely to explore lighted areas. MAM rats appeared hyperreactive to environmental stimuli, but not hyperactive. Finally, no MAM effect on behavior was as large as that on brain weight. Thus, as with clinical findings, rat micrencephalics are more remarkable for functional sparing than for behavioral abnormalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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The effects of high-energy radiation on pre- and neonatal development, the adult nervous system, learning and performance, and sensory functions are described. Though the number of available studies are few, there is evidence to suggest that: (1) the adult nervous system is relatively radioresistant; (2) learning functions are relatively unaffected by lethal or sublethal dosages of radiation; (3) hearing acuity and thresholds to dark adaptation increase as a result of radiation; and (4) the fetal nervous system is relatively radiosensitive. There is a need for more studies assessing the behavioral effects of radiation. 70-item bibliography. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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High densities of atriopeptin-immunoreactive fibers and of highly specific and selective atriopeptin receptor sites are present in brain areas involved in animal behavior. The possible influence of these peptides on behavior was thus investigated in adult rats. The intracerebroventricular injection of atriopeptin II modified male sexual behavior (reduction in mount latency) at the dose of 5 micrograms/animal; lower and higher doses were ineffective. Open-field behavior was also modified by i.c.v. atriopeptin II at the doses of 5 and 10 micrograms/rat, which induced an increase in the number of external and internal crossings and of external rearings. Finally, in fasted rats, atriopeptin II, at the dose of 10 micrograms/rat, significantly increased the amount of food intake 30 and 60 min after injection. These findings indicate that atriopeptins may modify different animal behaviors.  相似文献   

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In Exp I, 42 Ss (mean age 30.4 yrs) tracked a moving target and monitored lights after receiving sublingual drops that contained either water, sodium nitrate (4.5, 45, 450, or 4,500 ppm), or sodium fluoride (.1, 1, 10, or 100 ppm). Dosage levels equaled, exceeded, or fell below those of municipal waters. In Exp II, 20 females performed this task after receiving sublingual drops of the same test substances in a repeated measures design; dosage levels equaled or exceeded levels found in municipal waters by 100 or 500 times. Neither type nor amount of chemical affected primary task performance; however, after receiving sublingual drops in Exp I, Ss paid less attention to lights on their right. In Exp II, Ss made more errors and had longer response latencies after they received moderate and very high concentrations of test substances. It is concluded that challenge testing is a safe but effective technique for provoking and studying reactions to chemicals when combined with a sensitive measure of sensorimotor performance. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Research studies have provided advancements in knowledge regarding retinopathy of prematurity. Examination identifies premature infants with threshold disease that indicates need for treatment. It is hoped that timely evaluation and treatment will reduce the incidence of ROP-related blindiness.  相似文献   

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Retinopathy of prematurity (ROP) is a disease characterized by abnormal growth of retinal blood vessels in the eyes of premature infants. It is especially severe in the tiniest, most premature infants, whose chances of survival have increased with advances in neonatal care. Infants in whom ROP is diagnosed during the perinatal period are at risk for ocular abnormalities and for deficits in visual function. This article reviews the classification of ROP, summarizes current recommendations for screening of ROP in the perinatal period, and describes recent findings with respect to ocular and visual acuity outcomes of infants with ROP.  相似文献   

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Intraoral infusion of milk to the rat fetus promoted changes in behavior (mouth and rearlimb movements), reduced responsiveness to perioral cutaneous stimulation, and resulted in expression of a fetal stretch response. Milk also altered the temporal organization of fetal movements over periods up to 30 min. The orosensory characteristics of milk, in the absence of ingestion, was sufficient to evoke these behavioral effects. Reduced responsiveness to a perioral stimulus had a rapid onset (  相似文献   

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Previous results show that endogenous opioid systems mediate affective responses in neonatal rats. Opioids modulate isolation-induced ultrasonic vocalizations and analgesia. This study further examines the behavioral effects of κ-receptor-system stimulation on 10-day-old rats. With the agonist U50,488, response to isolation in terms of vocalizations, activity levels, and pain sensitivity was tested. In contrast to morphine's effects (primarily a μ-agonist), the κ-agonist U50,488 produced increased vocalizing and hyperactivity, although both opioid agonists caused analgesia. Isolation adds to the U50,488-mediated increase in the latency for paw withdrawal from heat. This study suggests that the kappa system provokes calling and activity as opposed to the quieting effects of μ-agonists found in previous studies. These differential effects may be due in part to the interaction of the opioid and dopamine systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Developed a bivariate model of response to antidepressant tricyclic medication and psychosocial interventions and conducted a test of the drug-response aspect of this model, using objectively defined nonpathognomonic behaviors. Repeated measures ANOVA and interrupted time-series analyses were used to test whether tricyclics affected different constellations of behavior in 30 depressed inpatients. Results show that drug interventions increased the frequencies of activity-related behaviors only; however, positive clinical response was related to elevated levels of both activity-related and interpersonal behaviors. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Albino rats, 0, 9, 12, 15, 18, 21 or greater than 90 days of age, were given a mid-thoracic spinal cord transection. Evaluation of responses of the hindlimbs to a variety of behavioral tasks was begun on the day of surgery and at intervals throughout the postoperative survival period (up to 300 days). Two investigators, independently and without knowledge of the animals' ages or survival times, rated the response data. Histological study showed all transections to be complete. Large differences in behavior are observed when animals trasected at the neonatal stage (0-4 days of age) are compared with animals transected at the weanling stage (21-26 days of age)37. Results of the present investigation indicate a critical period near 15 days of age; animals lesioned prior to this age (0, 9, 12 days of age) show response development and recovery similar to the neonatally lesioned animal, whereas those animals lesioned at a later age (18, 21, greater than 90 days of age) show little recovery and are behaviorally similar to the weanling transected animal. In animals lesioned prior to the fifteenth postnatal day, postural responses appear depressed for a brief period but recover rapidly while most responses of animals in the older groups are depressed for longer periods and never attain the degree of recovery characteristic of the neonatally transected animal. Finally, like the neonatally transected animal, rats lesioned on the ninth and twelfth postnatal day develop certain responses at appropriate times relative to normal response development. If, however, these responses are mature and supraspinal control is present at the time of lesioning, they appear to be permanently depressed and fail to recover.  相似文献   

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Experiments examined how learning processes modulate tolerance to discriminative stimulus effects of morphine. Rats were trained to discriminate saline and 3.2 mg/kg morphine, and the doses of morphine required to mimic the training dose were determined before, during and after repeated treatment with saline or high doses of morphine (10 mg/kg, b.i.d.). In one set of experiments, training was either suspended or continued with saline and the original training dose during a 2-week treatment regimen. When training was suspended, high-dose morphine treatment increased the dose of morphine required for stimulus effects approximately 3-fold. Tolerance persisted 2 days after treatment ended, but disappeared within 7 days. In contrast, continued training with saline and 3.2 mg/kg morphine during high-dose treatment both attenuated development of tolerance and transferred control to lower doses. Transfer of control to lower doses appeared conditional upon recent termination of high-dose treatment, as it disappeared within 7 days. Treatment with saline did not change the doses of morphine required for stimulus effects under either training condition. A final experiment examined whether high-dose treatment could transfer control to higher doses of morphine. The treatment dose of 10 mg/kg morphine itself was used as the training dose during a 2-week treatment regimen. The dose of morphine required for stimulus effects increased 2- to 4-fold during treatment, but quickly returned to control values when treatment ended. These results extend previous findings that conditioning and pharmacodynamic processes jointly regulate development of tolerance to discriminative effects of morphine.  相似文献   

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Reared 212 randomly bred mice from birth in an enriched environment or in a standard control environment. Ss were tested for open-field activity and defecation, running wheel activity, exploration, and hoarding. After the hoarding tests all Ss were sacrificed and adrenal glands were removed and weighed. Significant main effects due to treatment were found on gross body weight at 38 days of age, open-field activity and defecation, running wheel activity measures, and exploration. Correlational analyses revealed that open-field activity was positively associated with exploratory behavior, and that the 2 activity measures were positively associated. In the control Ss, the running wheel measures were positively associated with hoarding performance. Results are discussed and compared with previous studies of environmental enrichment and mouse behavior. It is concluded that the effects of early enrichment upon open-field activity, running wheel activity, and exploration are well established. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Behavioral effects of estrogen receptor gene disruption in male mice   总被引:1,自引:0,他引:1  
Gonadal steroid hormones regulate sexually dimorphic development of brain functions and behaviors. Their nuclear receptors offer the opportunity to relate molecular events in neurons to simple instinctive mammalian behaviors. We have determined the role of estrogen receptor (ER) activation by endogenous estrogen in the development of male-typical behaviors by the use of transgenic estrogen-receptor-deficient (ERKO) mice. Surprisingly, in spite of the fact that they are infertile, ERKO mice showed normal motivation to mount females but they achieved less intromissions and virtually no ejaculations. Aggressive behaviors were dramatically reduced and male-typical offensive attacks were rarely displayed by ERKO males. Moreover, ER gene disruption demasculinized open-field behaviors. In the brain, despite the evident loss of functional ER protein, the androgen-dependent system appears to be normally present in ERKO mice. Together, these findings indicate that ER gene expression during development plays a major role in the organization of male-typical aggressive and emotional behaviors in addition to simple sexual behaviors.  相似文献   

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Subjective, performance-enhancing, dependence-producing, and adverse effects of methylxanthines are examined, based on computerized searches (i.e., Medline and PsycLIT). High doses (>3 mg/kg) of caffeine in children who consume little caffeine produce negative subjective effects such as nervousness, jitteriness, stomachaches, and nausea. Whether lower doses produce positive subjective effects has not been adequately tested. Caffeine appears to slightly improve vigilance performance and decrease reaction time in healthy children who habitually consume caffeine but does not consistently improve performance in children with attention deficit-hyperactivity disorder. Early studies suggest caffeine self-administration and withdrawal can occur in some adolescent soda drinkers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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A total of 33 male psychiatric patients who participated in a token system were exposed to changes in the token price of available commodities in 2 experiments. In Exp I the price of cigarettes was first raised, then lowered. As predicted, consumption of cigarettes decreased during price increases and increased during price decreases. Contrary to expectations, Ss did not consume less of other commodities or increase their earnings in order to purchase cigarettes at the higher prices. In Exp II, which again raised and lowered the price of cigarettes, evidence was found for the notion that the proportional price change rather than the absolute price change governed cigarette consumption behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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The use of perches to enrich the environment of group-housed Japanese monkeys (Macaca fuscata) was assessed. When monkeys were housed in a cage which contained eight wooden perches to increase the usable space, the rate of agonistic interactions as well as the rates of spatial proximity and social grooming decreased in comparison with those evident when they were housed in a cage without such perches. These results suggest that agonistic interactions were reduced which are likely to occur more frequently in crowded conditions and the monkeys displayed affiliative behavior such as social grooming more frequently in a cage without perches, i.e., more crowded conditions, than in a cage with perches. Attempts to enrich the environment of group-housed monkeys may lead to a better understanding of their behavioral flexibility and social adjustment.  相似文献   

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