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891.
Patterns of memory failure after scopolamine treatment: implications for cholinergic hypotheses of dementia 总被引:3,自引:0,他引:3
To test the idea that scopolamine provides a suitable pharmacological model of the memory defects associated with cortical or subcortical dementias, we assessed memory on a battery of tasks in healthy young normal subjects who received 0.5 mg scopolamine, 0.1-0.2 mg glycopyrrolate or physiological saline, once each on three separate occasions, and compared the pattern of memory failure induced by scopolamine to that observed on the same tasks in patients with Alzheimer's disease (AD) or Huntington's disease (HD). In agreement with previous reports, scopolamine impaired acquisition and delayed recall of a 14-word list and disrupted retention on the Brown-Peterson distractor task, whereas the peripherally active anticholinergic glycopyrrolate was without effect. However, under scopolamine the pattern of errors made on these memory tasks was quite different from that seen in patients with AD. Scopolamine did not increase the number of false positive errors on delayed recognition of the word list and also failed to increase the number of prior-item intrusions on the Brown-Peterson task. Also, scopolamine did not impair learning of a symbol-digit paired-associate task, and did not reduce the number of words retrieved or increase the number of words repeated on a standardized verbal fluency test. When the effects of scopolamine on memory were compared to the pattern of impairments observed in demented patients with HD, several differences were found. Although scopolamine clearly produces deficits on some measures of anterograde memory, the present findings question whether anticholinergic drugs adequately mimic the full range of memory impairments observed in cortical or subcortical dementias. 相似文献
892.
Retrospective coding in pigeons' delayed matching-to-sample 总被引:2,自引:0,他引:2
P J Urcuioli T R Zentall 《Journal of experimental psychology. Animal behavior processes》1986,12(1):69-77
In this study we examined how coding processes in pigeons' delayed matching-to-sample were affected by the stimuli to be remembered. In Experiment 1, two groups of pigeons initially learned 0-delay matching-to-sample with identical comparison stimuli (vertical and horizontal lines) but with different sample stimuli (red and green hues or vertical and horizontal lines). Longer delays were then introduced between sample offset and comparison onset to assess whether pigeons were prospectively coding the same events (viz., the correct line comparisons) or retrospectively coding different events (viz., their respective sample stimuli). The hue-sample group matched more accurately and showed a slower rate of forgetting than the line-sample group. In Experiment 2, pigeons were trained with either hues or lines as both sample and comparison stimuli, or with hue samples and line comparisons or vice versa. Subsequent delay tests revealed that the hue-sample groups remembered more accurately and generally showed slower rates of forgetting than the line-sample groups. Comparison dimension had little or no effect on performance. Together, these data suggest that pigeons retrospectively code the samples in delayed matching-to-sample. 相似文献
893.
T R Zentall P Jackson-Smith J A Jagielo G B Nallan 《Journal of experimental psychology. Animal behavior processes》1986,12(2):153-159
Categorical coding is the tendency to respond similarly to discriminated stimuli. Past research indicates that pigeons can categorize colors according to at least three spectral regions. Two present experiments assessed the categorical coding of shapes and the existence of a higher order color category (all colors). Pigeons were trained on two independent tasks (matching-to-sample, and oddity-from-sample). One task involved red and a plus sign, the other a circle and green. On test trials one of the two comparison stimuli from one task was replaced by one of the stimuli from the other task. Differential performance based on which of the two stimuli from the other task was introduced suggested categorical coding rules. In Experiment 1 evidence for the categorical coding of sample shapes was found. Categorical color coding was also found; however, it was the comparison stimuli rather than the samples that were categorically coded. Experiment 2 replicated the categorical shape sample effect and ruled out the possibility that the particular colors used were responsible for the categorical coding of comparison stimuli. Overall, the results indicate that pigeons can develop categorical rules involving shapes and colors and that the color categories can be hierarchical. 相似文献
894.
Sex differences in the effects of gonadectomy on amphetamine-induced rotational behavior in rats 总被引:2,自引:0,他引:2
The effects of gonadectomy on amphetamine-induced rotational behavior were studied in male and female rats. Different systemic doses were used to produce equivalent brain concentrations of the drug in each group, thereby controlling for sex differences in the metabolism of amphetamine. Ovariectomy of female rats significantly attenuated amphetamine-induced rotation, whereas castration of males was without effect. The results support the idea that in females, the endogenous gonadal hormones facilitate functional activity in the mesostriatal dopamine system. 相似文献
895.
Initial environment influences amphetamine-induced stereotypy: subsequently environment change has little effect 总被引:1,自引:0,他引:1
Saline-treated and amphetamine-treated (7 mg/kg, ip, immediate) male rats from a Sprague-Dawley substrain were observed in two test environments designed to elicit different investigative responses in normal rats. Snout contact with the substrate was generated by placing the rat in a small enclosed cage. Absence of snout contact was induced by placement of the rat on a square elevated platform. Detailed ethological records were kept of locomotion, rearing, sitting, grooming, gnawing, and sleeping throughout the 90-min session. Amphetamine-treated rats incorporated environmentally contingent bodily postures into their forms of stereotyped behavior. The postures were characteristic of those evinced initially by the saline-treated rats in the same test environment. The control rats showed appropriate changes in their investigative behavior when the apparatus was changed at 10 and at 30 min postinjection. The amphetamine-treated rats, however, were completely unresponsive to such changes at 30 min and only partially so at 10 min postinjection. It was concluded that there is a temporal gradient of decreasing readiness to modify repetitive behavior after a single, large dose of amphetamine. 相似文献
896.
This paper compares LD and non-LD peers on eight variants of the oddity task. This study is part of a larger programmatic research effort aimed at the development of a screening test to detect preschool children who currently pass existing screening tests but, nonetheless, subsequently experience school failure. The theoretical orientation of this approach is to assess active, ongoing cognitive processing ability. The oddity task, which can be structured to assess such processing ability, was evaluated in the present study as a potential component of this screening test. Consistent with a priori predictions, the data resulted in strong group and developmental differences. Oddity performance increased over age, with the non-LD children performing consistently better than their LD peers at each age. Perceptual and conceptual factors were manipulated across the oddity variations, and both factors contributed to group differences. These results were discussed in relationship to early diagnosis and prognosis for learning disabilities that might result from deficiencies in abstract processing ability.The authors would like to express their thanks to the schools, teachers, and students who participated in this study. This research was supported in part by the Mailman Foundation and FDLRS/MAILMAN, a specialized university center of the Florida Diagnostic Learning Resources System, funded through State General Revenue appropriation to provide multidisciplinary evaluation services in exceptional student education programs. 相似文献
897.
Assessing depression in community samples of children using self-report inventories: Ethical considerations 总被引:2,自引:0,他引:2
Daniel J. Burbach Jennifer G. Farha Joseph S. Thorpe 《Journal of abnormal child psychology》1986,14(4):579-589
Although the methodological problems associated with the use of children's self-report depression inventories have previously been discussed in detail, the ethical problems related to the use of these instruments have been largely ignored. The primary purpose of this survey study was to determine how childhood depression researchers have prepared for and responded to children from community (i.e., nonclinic) samples whose nonanonymous scores on self-report depression inventories have indicated that they might be severely depressed or suicidal. Several recommendations, based upon (a) the results of this survey study, (b) the existing literature relevant to the ethical responsibilities of investigators who conduct research with children, and (c) our own experiences with these instruments and populations, are made to assist researchers in their attempts to use these inventories in an ethical manner.The authors would like to thank those childhood depression researchers who were kind enough to return completed surveys. 相似文献
898.
899.
A common technique in research into cerebral asymmetry in both normal and clinical populations involves the use of lateralized visual displays. The validity of this approach depends on several generally implicit assumptions about the character of the cognitive processes involved. For example, when words are used as stimuli, cognitive processing is assumed to involve either "whole-word" or "ends-in" analysis. In this way, both hemispheres are assumed to have equal opportunities to recognize the word. These assumptions are critical, because if they are wrong, explanations based on established perceptual principles may provide a sufficient and more parsimonious explanation for hemifield asymmetries than hemispheric specialization theories. This point is developed and illustrated with particular reference to word recognition and classification. From a purely perceptual viewpoint, the right visual field advantage observed in tasks using word stimuli is to be expected given the presence of systematic biases in favor of initial characters or features of words and the relationship between retinal eccentricity and visual acuity. In other words, there is no need nor justification for a hemispheric account of visual field differences in such tasks. Some of the limiting conditions and theoretical implications of this argument are identified and discussed. 相似文献
900.
Stress and coping in early adolescence: relationships to substance use in urban school samples 总被引:5,自引:0,他引:5
T A Wills 《Health psychology》1986,5(6):503-529
Measures of stress and coping were obtained from two cohorts of urban adolescents during the seventh- to eighth-grade period and were related to indices of cigarette smoking and alcohol use. Predictions were derived from a stress coping model of substance use. Stress was indexed by measures of subjective stress, recent events, and major life events; coping was assessed by behavior-based and intention-based methods. Concurrent and prospective analyses were consistent with predictions, indicating that stress was positively related to substance use, and four coping mechanisms (behavioral coping, cognitive coping, adult social support, and relaxation) were inversely related to substance use. Two types of predicted interactions, Stress X Coping and Positive X Negative Events, were found. Measures indexing peer support, distraction coping, and aggressive coping were positively related to substance use, independent of other predictors. Implications for substance use theory and prevention research are discussed. 相似文献