The vestibulo-ocular reflex (VOR) adaptation is an ideal model for investigating how the neurosteroid 17 beta-estradiol (E2) contributes to the modification of behavior by regulating synaptic activities. We hypothesized that E2 impacts VOR adaptation by affecting cerebellar synaptic plasticity at the parallel fiber–Purkinje cell (PF) synapse. To verify this hypothesis, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in adaptation of the VOR in male rats using an oral dose (2.5 mg/kg) of the aromatase (...) inhibitor letrozole. We also assessed the effect of letrozole on synaptic plasticity at the PF synapse in vitro, using cerebellar slices from male rats. We found that letrozole acutely impaired both gain increases and decreases adaptation of the VOR without altering basal ocular-motor performance. Moreover, letrozole prevented long-term potentiation at the PF synapse (PF-LTP) without affecting long-term depression (PF-LTD). Thus, in male rats neurosteroid E2 has a relevant impact on VOR adaptation and affects exclusively PF-LTP. These findings suggest that E2 might regulate changes in VOR adaptation by acting locally on cerebellar and extra-cerebellar synaptic plasticity sites. (shrink)

Neurosteroid 17 beta-estradiol (E2) is a steroid synthesized de novo in the nervous system that might influence neuronal activity and behavior. Nevertheless, the impact of E2 on the functioning of those neural systems in which it is slightly synthesized is less questioned. The vestibulo-ocular reflex (VOR) adaptation, may provide an ideal arena for investigating this issue. Indeed, E2 modulates cerebellar parallel fiber-Purkinje cell synaptic plasticity that underlies encoding of VOR adaptation. Moreover, aromatase expression in the cerebellum of adult rodents is (...) maintained at very low levels and localized to Purkinje cells. The significance of age-related maintenance of low levels of aromatase expression in the cerebellum on behavior, however, has yet to be explored. Our aim in this study was to determine whether E2 synthesis exerts an effective and persistent modulation of VOR adaptation in adult male rats. To answer this question, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in VOR adaptation using an oral dose (2.5 mg/kg) of the aromatase inhibitor Letrozole in peri-pubertal and post-pubertal male rats. We found that Letrozole acutely impaired gain increases and decreases in VOR adaptation without altering basal ocular-motor performance and that these effects were similar in peri-pubertal and post-pubertal rats. Thus, in adult male rats neurosteroid E2 effectively modulates VOR adaptation in both of the periods studied. These findings imply that the adult cerebellum uses E2 synthesis for modulating motor memory formation and suggest that low and extremely localized E2 production may play a role in adaptive phenomena. (shrink)

The specificity of different perceptions must correspond to the metaphysical lines of the world. The metaphysical fault lines of being find expression in the peculiarities of the psychological structure of our experience. Ontologically, one would say: metaphysics produces psychology; psychologically, one would say the opposite: psychology determines our metaphysical structures. But symbolically, we will say, as we have said already: the metaphysical is expressed in the psychological, the psychological expresses metaphysics.

Negative campaign advertising is a major component of the electoral landscape, and has received much attention in the literature. In many studies, political scientists have tried to explain why some campaign ads contain more negative messages than others and to identify the determinants of this form of campaign behavior. In recent years, a number of studies have acknowledged the differences between alternative measures of negativity, but, in most cases, it is assumed that since these measures are highly correlated, they are (...) unidimensional and essentially interchangeable. In this article, we argue that much of the debate in the literature over negative campaigning is a result of inadequate operationalizations of negativity. Although debates over negativity have often been framed in conceptual terms, there is a methodological explanation for why they persist We begin our analysis by constructing reliable scales of negativity, and model them with salient predictors reported in the literature as significantly associated with campaign attacks. Our findings show that scaling does matter, and while some of the explanatory variables are robust predictors of negativity, most of them are not. (shrink)

In the period of the general crisis of capitalism and the revolutionary transition from capitalism to socialism, the trends and prospects for the historical development of society have become the central question in the ideological struggle.

This book challenges the widespread assumption of the incompatibility of evolution and the biological design argument. Kojonen analyzes the traditional arguments for incompatibility, and argues for salvaging the idea of design in a way that is fully compatible with evolutionary biology. Relating current views to their intellectual history, Kojonen steers a course that avoids common pitfalls such as the problems of the God of the gaps, the problem of natural evil, and the traditional Humean and Darwinian critiques. The resulting deconstruction (...) of the opposition between evolution and design has the potential to transform this important debate. (shrink)

As the black clouds of war lift from the surface of the Continents of Europe and Nearer Asia, the eye looks round upon a shattered civilization. The once busy tide of labour on the field and in the factory, beneath the soil and within dock, ebbs slowly away; the accustomed rewards of toil, food, warmth and clothing, become daily more difficult of attainment. Authority trembles in its seat, and money loses its once all-powerful attraction. Inevitably the scholar recalls the tale (...) of the Decline and Fall of the Roman-Hellenistic world, and calculates the prospect of a second millennium of darkness and suffering. And he is not unconscious that he stands himself accused of having brought about, or at least failed to avert, the doom of the nations. For, he is told, the governing classes of all the nations that clashed in mutual destructiveness were constituted of men brought up in the classical tradition, whose minds in their fresh boyhood were fed on the so-called glories of Alexander the Great and of Julius Caesar, and who sought in rivalry to win, each for his nation, the haughty supremacy of imperial Rome. And he hears the clamour of those who demand a clean sweep of the false ideals and selfish ambitions of the past, and the building upon new foundations of a world of contentment and peace, inspired by the basic conception of a citizenship in which no man shall seek his own gain at the cost of another's loss. Towards the building up of this new world, it is claimed, the study of the past can do nothing to help; by effacing itself it will cease to be a hindrance. And in response to this accusation there arise in all directions schemes for a reconstructed world, a reconstituted nation, and a new education, which shall be alike in this one point—that they take for granted the elimination of the study of antiquity and the disappearance of the atmosphere of the Humanities. (shrink)

In the whole theory of the Latin tenses there is no more popular item than this explanation by Roby of the use of the pluperfect indicative in unreal conditional sentences. Far the most familiar instance is that in Horace , ‘me truncus illapsus cerebro sustulerat, nisi Faunus ictum dextra leuasset.’.

Keine ausführliche Beschreibung für "Geschichte der antiken Philosophie" verfügbar.