Reversal of Relative Thresholds for Synaptic Facilitation and Increased Excitability Induced by Serotonin and Tail Nerve Stimulation inAplysiaSensory Neurons

Tail shock induces reflex sensitization inAplysiaand, in parallel, induces a number of modulatory effects in central neurons, such as increased excitability in tail sensory neurons (SNs) and facilitation of synaptic transmission from SNs to motor neurons. Both of these modulatory effects are mimicked by exogenous application of serotonin (5HT) or electrical stimulation of the tail nerve P9. In the present study we examined the activation thresholds for increased excitability and synaptic facilitation induced by either 5HT or P9 stimulation. We found that the concentration of 5HT sufficient to produce a significant increase in excitability produced no significant synaptic facilitation and, conversely, that the intensity of nerve stimulation sufficient to produce significant synaptic facilitation produced no excitability changes. This reversal of relative thresholds for these modulatory effects may reflect the differential access of exogenous 5HT and endogenous 5HT (released by tail nerve stimulation) to the SN cell body and synaptic terminals, respectively.     

WHY BIOETHICS NEEDS THE PHILOSOPHY OF MEDICINE: SOME IMPLICATIONS OF REFLECTION ON CONCEPTS OF HEALTH AND DISEASE

Germund Hesslow has argued that concepts of health and disease serve no important scientific, clinical, or ethical function. However, this conclusion depends upon the particular concept of disease he espouses; namely, on Boorse's functional notion. The fact/value split embodied in the functional notion of disease leads to a sharp split between the “science” of medicine and bioethics, making the philosophy of medicine irrelevant for both. By placing this disease concept in the broader context of medical history, I shall show that it does capture an essential part of modern medical ideology. However, it is also a self-contradictory notion. By making explicit the value desiderata of medical nosologies, a reconfiguration of the relation between medicine, bioethics, and the philosophy of medicine is initiated. This, in turn, will involve a recovery of the caring dimensions of medicine, and thus a more humane practice.     

行为与脑的关系及其与机体其它属性间的相互作用的研究──心理学研究展望

“二十一世纪的心理学”的论题是当今许多科学家感兴趣的．这种预测是一种想象与现实相结合的尝试。审视过去和现在．心理学未来的雏形的基础可能是行为与脑的关系及其与生命其它属性之间的相互作用。     

Isoluminance and contingent color aftereffects

In the typical induction of the orientation-contingent color aftereffect (CCAE), the stimuli are composed of elements that differ in both color and luminance. Three experiments are reported that show that chromatic contrast between stimulus elements is insufficient for the induction of the orientation-CCAE and that luminance contrast is necessary. These experiments expand on previous research concerned with the role of luminance contrast in the induction of orientation-CCAEs by eliminating alternative explanations.     

Causal Attributions for Poorly Performing Projects: Their Effect on Project Continuation Decisions

This study examined the escalation problem within an attribution theory framework. Students read a case scenario containing causal attribution information that described a poorly performing project under their supervision. They made estimates of its future success, as well as a decision whether to continue it. Perceived stability of causality had the primary effect on expectancy of success. A project whose performance downturn was attributed to a stable cause had a lower expectancy. Locus of causality had a smaller but still significant effect. Project downturns attributed to internal causes had a lower expectancy. Expectancy of success was significantly correlated with project continuation decisions. Discrepancies between these results and those reported by Staw and Ross (1978) are accounted for in terms of Weiner's (1985, 1986) attributional analysis.     

De Re Language,De Re Eliminability,and the Essential Limits of Both

De re modality is eliminable if there is an effective translation of all wffs into non-de re equivalents. We cannot have logical equivalence unless logic has odd theses, but we can have material equivalence by banning all essences, something the non-de re facts let us do, or by giving everything such humdrum essences as self-identity and banning the more interesting ones. Eliminability cannot be got from weaker assumptions, nor independent ones of even modest generality. The net philosophical import is that, quite apart from the merits of essentialism, de re language has scant utility.     

Politeness and memory for the wording of remarks

Three experiments were conducted to examine whether people spontaneously remember the wording used to convey politeness. In all experiments, subjects heard statements varying in politeness that had been made by either a high-status (e.g., a professor) or equal-status (e.g., another student) speaker. Subjects’ incidental memory for these statements was then tested with either a recognition (Experiments 1 and 3) or a recall (Experiment 2) procedure. As expected, there was evidence of significant memory for wording that conveyed politeness, and subjects were more likely to remember forms that were incongruous with the speaker’s status. There was also some evidence that subjects encoded the politeness of a remark even when they were unable to recall the specific remark. The results demonstrate the role of the interpersonal dimension in the processing of language in context.     

End-Weight from the Speaker's Perspective

Explanations of the tendency to put long, complex constituents at the ends of sentences (end-weight) usually take the listener's perspective, claiming it facilitates parsing. I argue for a speaker-oriented explanation of end-weight, based on how it facilitates utterance planning. Parsing is facilitated when as much tree structure as possible can be determined early in the string, but production is easiest when options for how to continue are kept open. That is, listeners should prefer early commitment and speakers should prefer late commitment. Corpus data show that different verbs exhibit different rates of word-order variation that are systematically related to differences in subcategorization possibilities in just the way predicted by a strategy of late commitment. Thus, a speaker-based account of lexical preferences in word ordering does a better job of explaining variation in weight effects than a listener-based account.