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911.
This article explores the ethical concept of neutrality through use of a psychiatric clinical vignette. In this case a psychiatry resident is faced with the treatment of a patient who was found by the FBI to be in possession of child pornography. Although not accused of any other crimes, the patient was a fugitive from the law and requesting treatment for pedophilia. Faced with the pressures of limited resources and anxiety about the patient's dangerousness to others, the resident and his supervisor tried to strike a balance between the ethical principles of neutrality and beneficence. Through this vignette, the importance of neutrality, as well as how it can be compromised by other pressures such as expediency and anxiety, is explored. 相似文献
912.
913.
Recognition memory is usually regarded as a judgment based on trace strength or familiarity. But recognition may also be accomplished
by constraining retrieval so that only sought after information comes to mind (source-constrained retrieval). We introduce amemory-for-foils paradigm that provides evidence for source-constrained retrieval in recognition memory (Experiment 1) and source memory (Experiment
2). In this paradigm, subjects studied words under deep or shallow encoding conditions and were given a memory test (recognition
or source) that required them to discriminate between new items (foils) and either deep or shallow targets. A final recognition
test was used to examine memory for the foils. In both experiments, foil memory was superior when subjects attempted to retrieve
deep rather than shallow targets on the earlier test. These findings support a sourceconstrained retrieval view of cognitive
control by demonstrating qualitative differences in the basis for memory performance. 相似文献
914.
Holahan MR 《Neurobiology of learning and memory》2005,84(2):124-131
Evidence collected from rodent models of memory storage suggests that rapid forms of learning engage the involvement of multiple brain regions each of which may participate in a different component of information processing. The present study used temporary inactivation of the amygdala and hippocampus during different phases of information processing on a one-trial appetitive-conditioning task to examine how these two regions might participate in the storage of appetitive memories. Male Long Evans rats were chronically implanted into the amygdala or dorsal hippocampus and food deprived. Rats were trained on a radial maze conditioned cue preference task where training occurred in one 40-min session and testing took place 24 h later. The amygdala or hippocampus was inactivated separately with muscimol (50 ng/microl) injected immediately before or after training, or immediately before testing. Saline-injected rats displayed a conditioned preference by spending more time in the arm that previously contained food than in the arm that did not contain food. Muscimol injected into the amygdala before training or testing blocked the conditioned preference. Muscimol injected into the hippocampus immediately after training blocked the conditioned preference. These results suggest that the processing of memories may require multiple contributions from separate brain systems for at least short-term (24 h) storage. The resulting output from each system may converge on a similar downstream target to influence behavior. 相似文献
915.
The threat of bioterrorism, the emergence of the SARS epidemic, and a recent focus on professionalism among physicians, present a timely opportunity for a review of, and renewed commitment to, physician obligations to care for patients during epidemics. The professional obligation to care for contagious patients is part of a larger "duty to treat," which historically became accepted when 1) a risk of nosocomial infection was perceived, 2) an organized professional body existed to promote the duty, and 3) the public came to rely on the duty. Physicians' responses to epidemics from the Hippocratic era to the present suggests an evolving acceptance of the professional duty to treat contagious patients, reaching a long-held peak between 1847 and the 1950's. There has been some professional retrenchment against this duty to treat in the last 40 years but, we argue, conditions favoring acceptance of the duty are met today. A renewed embrace of physicians' duty to treat patients during epidemics, despite conditions of personal risk, might strengthen medicine's relationship with society, improve society's capacity to prepare for threats such as bioterrorism and new epidemics, and contribute to the development of a more robust and meaningful medical professionalism. 相似文献
916.
People's causal attributions for events in their lives have been shown to relate to individual and interpersonal outcomes. Groups and organizations also make causal attributions, and this article examines whether their publicly communicated attributions predict organizational-level outcomes. By content analyzing attributions contained in corporate annual reports from 14 companies during a 21-year period, the authors found that organizations that made "self disserving" attributions- internal and controllable attributions for negative events-had higher stock prices 1 year later. The authors argue that claiming personal responsibility for negative events made the organizations appear more in control, leading to more positive impressions. 相似文献
917.
In a previous study, search for a notched-disk target abutting a square among complete-disk nontargets and squares was inefficient in 250-ms exposures, but relatively efficient in 100-ms exposures. This finding was interpreted as evidence that amodal completion proceeds through a mosaic and then a completion stage, with the latter preempting the former. We used the same target but changed its context: Nontargets were instead notched disks near squares. Task set was also different: Participants searched for a complete disk. Contrary to the prediction of the preemption model, search was efficient in the 100-ms condition and inefficient in the 250-ms condition. We propose that in both the present and the previous studies, the target was ambiguous, and task set and context affected how it was perceived. In both experiments, set effects were evident for 100-ms exposures; context effects were evident for 250-ms exposures. 相似文献
918.
919.
Nicotinic cholinergic synaptic mechanisms in the ventral tegmental area contribute to nicotine addiction 总被引:16,自引:0,他引:16 下载免费PDF全文
Pidoplichko VI Noguchi J Areola OO Liang Y Peterson J Zhang T Dani JA 《Learning & memory (Cold Spring Harbor, N.Y.)》2004,11(1):60-69
Tobacco use is a major health problem that is estimated to cause 4 million deaths a year worldwide. Nicotine is the main addictive component of tobacco. It acts as an agonist to activate and desensitize nicotinic acetylcholine receptors (nAChRs). A component of nicotine's addictive power is attributable to actions on the mesolimbic dopaminergic system, which serves a fundamental role in the acquisition of behaviors that are inappropriately reinforced by addictive drugs. Here we show that nicotine, in the same concentration and time ranges as obtained from tobacco, has three main actions that regulate the activity of midbrain dopamine (DA) neurons. Nicotine first activates and then desensitizes nAChRs on the DA neurons. This process directly excites the DA neurons for a short period of time before the nAChRs desensitize. Nicotine also enhances glutamatergic excitation and decreases GABAergic inhibition onto DA neurons. These events increase the probability for synaptic plasticity, such as long-term potentiation. The short-lived direct excitation of the DA neurons coupled with the enhanced glutamatergic afferent activity provides the presynaptic and postsynaptic coincidence necessary to initiate synaptic potentiation. In total, these synaptic events lead to a relatively long-lasting heightened activity of midbrain DA neurons. Consistent with other summarized studies, this work indicates that the synaptic changes normally associated with learning and memory can be influenced and commandeered during the nicotine addiction process. 相似文献
920.
Auditory trace fear conditioning is a hippocampus-dependent learning task that requires animals to associate an auditory conditioned stimulus (CS) and a fear-producing shock-unconditioned stimulus (US) that are separated by an empty 20-s trace interval. Previous studies have shown that aging impairs learning performance on hippocampus-dependent tasks. This study measured heart rate (HR) and freezing fear responses to determine if aging impairs hippocampus-dependent auditory trace fear conditioning in freely moving rats. Aging and Young rats received one long-trace fear conditioning session (10 trials). Each trial consisted of a tone-CS (5 s) and a shock-US separated by an empty 20-s trace interval. The next day rats received CS-alone retention trials. Young rats showed significantly larger HR and freezing responses on the initial CS-alone retention trials compared to the Aging rats. A control group of aging rats received fear conditioning trials with a short 1-s trace interval separating the CS and US. The Aging Short-Trace Group showed HR and freezing responses on the initial CS alone retention trials that were similar to the Young Long-Trace Group, but greater than the Aging Long-Trace Group. A second aging control group received unpaired CSs and USs, and showed no HR or freezing responses on CS-alone retention trials. These data show that HR and freezing are effective measures for detecting aging-related deficits in trace fear conditioning. 相似文献