The problem of switching in conditional behavior

This article reviews studies of various authors on the phenomenon of “switching,” which is observed in both classical and instrumental conditioning and consists in elicitation of different responses to the same conditional stimulus (CS) when it is applied in an environment different than the original one. The different responses include a decrease or an absence of the previously trained conditional response (CR), elicitation of an appetitive response instead a defensive one, or vice versa, as well as elicitation of two different instrumental CRs in the same trial. The studies suggest that, due to the repeated occurrence of CS in the same environment (E), also called “situation” or “context,” associations are formed between CS and E. Consequently, the CR is elicited to a compound CS+E rather than to CS alone. When the CS is applied alone in a different E than the original one, the previously formed associations are inactive and the CR cannot be elicited; this leads to switching. Studies also suggest that E plays a dominant role in conditioning compared with that of CS alone, which often appears to be only a trigger for eliciting the response. However, CS tested in a different E may still produce some components of the previously acquired CR, such as a general fear behavior to an originally defensive CS or an approach behavior to an originally alimentary CS. The environmental stimuli can be considered the “determining” stimuli that determine the kind of reaction to be elicited, or “tonic” stimuli that increase the tonus in the brain but do not elicit the CR. The “determining” or “tonic” stimuli do not seem to be a special class of stimuli. Instead, they are stimuli that initially can produce the CR (e.g., intertrial CRs), but by being not reinforced they become partly inhibited; nevertheless, due to associations with the reinforcement, they still can produce some excitement related to it, thus facilitating the CR.     

Bioterrorism, Embryonic Stem Cells, and Frankenstein

The stem cell controversy raises a fundamental question for humankind. Does science have a right to pursue knowledge whatever the cost? Our Enlightenment culture says yes. However, human history and literature are sending warning signals. Ethical issues impact the “knowledge for its own sake” imperative, and must be addressed.     

“You are our only hope”: Trading metaphorical “magic bullets” for stem cell “superheroes”

In the wake of two recent developments in stem cell research, it is a fitting time to reassess the claim that stem cells will radically transform the concept and function of medicine. The first is the U.S. Food and Drug Administration’s decision in January 2009 to approve Geron Corporation’s Phase I clinical trial using human embryonic stem cells for patients with spinal cord injuries. The second is the National Institutes of Health’s decision to permit federal funding of research using donated IVF human embryos in their July 2009 Guidelines on Human Stem Cell Research. We are now poised to see whether stem cell research can deliver on what it promises. However, what exactly does it promise and how? Moreover, who is doing the promising? Turning to the use of metaphor can help us to answer these questions and enable us to develop a better appreciation of the unique features of promised stem cell therapies. Indeed, metaphors have exerted profound influence in medicine, and it is fitting that we seek new metaphors for new therapies where appropriate. In this case, other metaphors such as magic bullets or the Holy Grail cannot capture what is unique about stem cells. Accordingly, I propose a new metaphor: the stem cell superhero. Stem cell superheroes are characterized by the following traits: they are seemingly capable of fighting the evil of virtually all disease (unlike “magic bullets”) and they seem to be our only hope of doing so, although to summon them we must make difficult moral choices. In the course of assessing the merits of three recent yet covert references to the superhero metaphor, I conclude that this powerful new paradigm employs a problematic logic (i.e., we cannot know that something is “our only hope”), but that the aspiration as such is a good one.     

Identification and categorization in visual search

Seven experiments were addressed to the general question of whether the identification of letters and numbers is a more rapid process than the categorization of such stimuli. Subjects were required to make a single response if a target stimulus specified by name (e.g., “A,” “2”) or designated by category class alone (e.g., “letter,” “number”) was presented in a trial. The principal findings were: (1) identification reaction times (RTs) were faster than categorization RTs: (2) RTs for targets shown without a context were faster than RTs for targets shown in the context of other stimuli; (3) identification RTs for targets shown in the context of stimuli from a different conceptual-taxonomic category were faster than RTs for targets shown in the context of stimuli from the same category only when target-context stimulus discriminability differencet were optimized. The results were interpreted in terms of a two-stage processing model in which context face,ors affect the duration of an initial encoding-scanning stage and search instruction (effective memory size) factors affect the duration of the memory comparison stage.     

高强度聚焦超声配合FOLFOX4方案治疗晚期肝癌的临床观察

观察高强度聚焦超声(HIFU)配合FOLFOX4方案治疗晚期肝癌的疗效和不良反应。将58例晚期肝癌患者随机分成两组:热疗+化疗组(热化组)采用HIFU配合FOLFOX4方案,对照组为单纯FOLFOX4(单化组)治疗。结果显示热化组CR0例,PR18例,SD7例,PD2例,总有效率64.28%;单化组CR0例,PR11例,SD11例,PD7例,总有效率36.67%,两组差异均有统计学意义(P0.05)。HIFU配合FOLFOX4方案,治疗晚期肝癌近期疗效尚可,毒副反应较轻,值得临床推广试用。     

AUDITORY SUCCESSIVE CONDITIONAL DISCRIMINATION AND AUDITORY STIMULUS EQUIVALENCE CLASSES

This paper describes an experimental demonstration of stimulus equivalence classes consisting entirely of auditory stimuli. Stimuli were digitized arbitrary syllables (e.g., “cug,” “vek”) presented via microcomputer. Training and testing were conducted with a two-choice auditory successive conditional discrimination procedure. On each trial, auditory samples and comparisons were presented successively. As each comparison was presented, a response location (a rectangle) appeared on the computer screen. After all stimuli for a trial were presented, subjects selected one of the response locations. Six subjects acquired the conditional discrimination baseline, 4 subjects demonstrated the formation of three-member auditory equivalence classes resulting from sample-S+ relations, and 1 subject demonstrated equivalence classes resulting from sample-S— relations. Four subjects received additional training and subsequently demonstrated expansion of the three-member classes to four members each.     

Negative priming and stimulus-response compatibility

The subjects in this study made incongruent naming responses to words and pictures that were presented on alternate trials (e.g., say “car” toBIKE). Their response time was longer if the correct response for the current trial was the name of the stimulus presented on the preceding trial, as compared with a control condition. These results suggest that the tendency to produce the (congruent) name of the stimulus is automatically activated and then inhibited. The “negative priming” effects appeared stronger for words where pictures were primes than for pictures where words were primes. The implications of these results for negative priming and stimulus-response compatibility are discussed.     

“Show Me” Bioethics and Politics

Missouri, the “Show Me State,” has become the epicenter of several important national public policy debates, including abortion rights, the right to choose and refuse medical treatment, and, most recently, early stem cell research. In this environment, the Center for Practical Bioethics (formerly, Midwest Bioethics Center) emerged and grew. The Center's role in these “cultural wars” is not to advocate for a particular position but to provide well researched and objective information, perspective, and advocacy for the ethical justification of policy positions; and to serve as a neutral convener and provider of a public forum for discussion. In this article, the Center's work on early stem cell research is a case study through which to argue that not only the Center, but also the field of bioethics has a critical role in the politics of public health policy.     

Negative priming insame-different matching: Further evidence for a central locus of inhibition

Responses to recently ignored information may be slower or less accurate than responses to information not recently encountered. Such negative priming effects imply that the mechanism of selective attention operates on unattended, as well as attended, information. In the present experiment, subjects judged the second and fourth letters of five-letter strings (e.g., BABAB) as “same” or “different.” Responses were slower when a target letter was identical to the distractors presented in the immediately preceding trial. This effect did not depend on which response was required on the current or preceding trial. The results suggest that ignored information is functionally disconnected from the response system as a whole, rather than from a specific response.     

Varying temporal placement during CS of an added stimulus correlated with non-delivery of UCS

This experiment extends Pavlov’s method of contrasts for training a stimulus discrimination to the case of the cardiac conditional response in the rhesus monkey. It explores the parameter of temporal placement of an additional stimulus (“CS₂”) within a 10-sec CS (or “CS₁”), with the appearance of the former stimulus on any trial signalling the absence of UCS (electric shock) on that trial. This experimental paradigm is a parallel to that of the “intruded stimulus” studies in operant conditioning. In both cases, several ways of describing the function of the added stimulus are possible, but all seem reducible to the same operational terms. Data were taken in the present study with respect to the form and latency of the cardiac rate changes produced by intrusion of CS₂ (light), across a range of placements varying from simultaneity with CS₁ (a different light) onset to two sec before UCS would have been delivered. The control of CS₂ over the cardiac rate CR was occasionally exhibited with a latency as short as three beats after stimulus onset. The order of CS₂ temporal placements to which a subject was exposed was a factor in determining the form of the conditioned cardiac rate response to CS₁.     

Pattern-directed attention in uncertain-frequency detection

The role of early pattern components as cues in uncertain frequency detection was investigated in four probe-signal experiments. Listeners heard two consecutive presentations of one of two 12-tone patterns in a noise background. One presentation of the pattern was complete, whereas the other was missing the 11th (primary) tone. Listeners were required to indicate which presentation was complete. On 20% of the test trials, the 11th component of the complete pattern was replaced with one of four probe tones. The results indicated that listeners were more sensitive to the primary tone than to probe tones, and this selective sensitivity changed on a trial-by-trial basis as a function of the attentional cues provided by early pattern components. The data suggested two cue functions: (1) an “informational” function in providing information regarding which of two primary tones is likely to occur on a given trial, and (2) a “frequency” function that “automatically” directs listening to an appropriate frequency range and narrows or “fine tunes,” the listening band.     

GENETIC AND REPRODUCTIVE TECHNOLOGIES IN THE LIGHT OF RELIGIOUS DIALOGUE

Since the gene splicing debates of the 1980s, the public has been exposed to an ongoing sequence of genetic and reproductive technologies. Many issue areas have outcomes that lose track of people's inner values or engender opposing religious viewpoints defying final resolution. This essay relocates the discussion of what is an acceptable application from the individual to the societal level, examining technologies that stand to address large numbers of people and thus call for policy resolution, rather than individual fiat, in their application. A major source of guidance is the “Genetic Frontiers” series of professional dialogues and conferences held by the National Conference for Community and Justice from 2002 to 2004. Genetic testing, human gene therapy, genetic engineering of plants and animals, and stem cell technology are examined. While differences in perspective on the beginning of life persist, a stepwise approach to the examination of genetic testing reveals areas of general agreement. Stewardship of life, human co‐creativity with the divine, and social justice help define the bounds of application of genetic engineering and therapy; compassionate care plays a major role in establishing stem cell policy. Active, sustained dialogue is a useful resource for enabling sharing of religious values and crystallization of policies.     

胰岛细胞再生研究的临床应用前景

胰岛细胞再生是治愈1型糖尿病和胰岛β细胞功能丧失的2型糖尿病的根本途径。体外再生和体内再生两种策略都是通过将干细胞或其他类型体细胞分化或转化为胰岛细胞后发挥胰岛素分泌功能,从而治疗糖尿病。基础研究显示,两者存在着各自的优势和面临的问题。胰岛细胞再生治疗的临床应用前景尚需要进一步加以考证。     

„Time is brain“ bei der schubförmigen Multiplen Sklerose

Background

Despite highly divergent time scales of disease evolution in multiple sclerosis (MS) and ischemic stroke, clear analogies are apparent that may point the way to optimization of MS treatment. Inflammatory disease activity and neurodegeneration may induce potentially irreversible damage to central nervous system structures and thus lead to permanent disability. For the treatment of MS early detection of disease activity and early immunotherapy or treatment optimization are pivotal determinants of long-term outcomes. Such therapeutic concepts may be described with the catchy phrase “time is brain” as coined for the acute thrombolytic treatment of ischemic stroke.

Results and discussion

For MS a “time is brain” concept would comprise an early initiation of first line therapy as well as sensitive and structured monitoring of disease activity under therapy in conjunction with a low threshold for timely treatment optimization to achieve sustained freedom from measurable disease activity. This approach may substantially improve the long-term outcome in patients who show insufficient response to platform therapies. The intersectorial collaboration in regional MS care networks involving office-based neurologists and specialized MS centers may facilitate the timely use of highly active therapies with their specific benefit-risk profiles thus supporting sustained stabilization of patient quality of life.

     

The“response” in behavior theory

The term“response” is a basic one in behavior theory, particularly reflex theory, but its definition is not clear. The origin of the term in the common vocabulary has affected its later extensions in the analysis of behavior. Some contemporary theorists accept the existence of two“types” of response, coordinating one with the Pavlovian conditioning procedure, the other with the operant conditioning procedure of the so-called“contingent” variety. Reservations are expressed here about such distinctions between response classes and conditioning paradigms, emphasizing the difficulties that arise from certain conventions and inadequacies in current definitions and conceptions of“response.” The critical nature of the problem for behavior theory is illustrated once again by the recent laboratory finding that a familiar and accepted conditional reflex, that of the“conditioned cardiac CR,” can be fractionated into“parts” and is therefore perhaps no longer to be treated as a single unitary“response.”     

How can a heterosexual man remove his body hair and retain his masculinity? Mapping stories of male body hair depilation

ABSTRACT

This study explores the gendered body hair removal norm and the meanings of male body hair by examining young people’s sense-making around male body hair removal. The novel technique of story completion was used to collect data from 102 psychology undergraduates. They were presented with a story “stem” featuring a young man (David) deciding to start body hair removal and asked to complete the stem. David was most often portrayed as a young heterosexual man who was excessively hairy, in the “wrong” places, was often subject to teasing and bullying, and was concerned about his diminished sexual capital. Hair removal did not always end “happily ever after” for David. While in some stories he “got the girl,” he was punished for his vanity and foolishness in others. These different endings arguably reflect currently ambivalent meanings around male body hair depilation. The production of a hairless, or less hairy, male body is both desirable and a potential threat to masculinity. The data spoke strongly to the power of social norms surrounding body hair practices and suggest that story completion provides a useful tool in interrogating the discourses that sustain these norms.     

肿瘤干细胞研究的进展及启示

肿瘤干细胞理论认为,肿瘤增长是由肿瘤中具有干细胞特性的细胞分裂增殖引起的。针对性地抑制肿瘤干细胞的增殖,能显著提高肿瘤治愈率。本文用哲学的观点对肿瘤干细胞假说的提出、验证、临床应用进行分析,对于深入认识肿瘤干细胞的本质、探索其分离方法、发现抑制其增殖的有效手段将起到积极作用。     

The ethical assessment of innovative therapies: Liver transplantation using living donors

Liver transplantation is the treatment of choice for many forms of liver disease. Unfortunately, the scarcity of cadaveric donor livers limits the availability of this technique. To improve the availability of liver transplantation, surgeons have developed the capability of removing a portion of liver from a live donor and transplanting it into a recipient. A few liver transplants using living donors have been performed worldwide. Our purpose was to analyze the ethics of liver transplants using living donors and to propose guidelines for the procedure before it was introduced in the United States. We used a process of “research ethics consultation” that involves a collaboration between clinical investigators and clinical ethicists. We concluded that it was ethically appropriate to perform liver transplantation using living donors in a small series of patients on a trial basis, and we published our ethical guidelines in a medical journal before the procedure was introduced. We recommend this prospective, public approach for the introduction of other innovative therapies in medicine and surgery.     

模拟网络信息主动增加特征的决策过程研究

与传统信息不同,网络信息具有可以主动增加的互动特征,本研究探讨这种特征对网络情境下决策加工过程的影响。通过改进的信息板技术追踪决策过程。实验一设置可否“主动增加信息”两种情境进行对照研究,发现引入主动增加功能后被试的搜索深度降低,先前知识的水平影响信息加工的模式;实验二设置可以连续要求增加信息的连续任务,比较不同的增加路径和选择阶段的影响,发现被试的搜索深度逐步降低,更多采用非补偿性的策略。两个实验均有超过半数的被试要求增加信息,连续任务有着32%的回头率,研究者推论在信息不断增加的情况下,被试的信息搜索行为更具选择性。