920 resultados para rapid object identification and tracking
Resumo:
In this article we propose a model to explain how voters' perceptions of their ideological proximity to a party affect their propensity to vote for that party. We argue that political knowledge plays a crucial moderating role in the relationship between party proximity and voting propensity. It is necessary, however, to distinguish between institutional knowledge (information about the political system) and party knowledge (information about the parties' left-right positions). An analysis of survey data from the 2007 Swiss federal elections supports our main hypothesis that party knowledge enhances the link between party proximity and voting propensity. Institutional knowledge may have additional influence, but clear evidence for this effect was obtained only for propensities to vote for the Swiss People's Party (SVP). Overall, the impact of political knowledge was found to be substantial, even after controlling for the outstanding influence of party identification and other predictors of voting propensities
Resumo:
Approaching or looming sounds (L-sounds) have been shown to selectively increase visual cortex excitability [Romei, V., Murray, M. M., Cappe, C., & Thut, G. Preperceptual and stimulus-selective enhancement of low-level human visual cortex excitability by sounds. Current Biology, 19, 1799-1805, 2009]. These cross-modal effects start at an early, preperceptual stage of sound processing and persist with increasing sound duration. Here, we identified individual factors contributing to cross-modal effects on visual cortex excitability and studied the persistence of effects after sound offset. To this end, we probed the impact of different L-sound velocities on phosphene perception postsound as a function of individual auditory versus visual preference/dominance using single-pulse TMS over the occipital pole. We found that the boosting of phosphene perception by L-sounds continued for several tens of milliseconds after the end of the L-sound and was temporally sensitive to different L-sound profiles (velocities). In addition, we found that this depended on an individual's preferred sensory modality (auditory vs. visual) as determined through a divided attention task (attentional preference), but not on their simple threshold detection level per sensory modality. Whereas individuals with "visual preference" showed enhanced phosphene perception irrespective of L-sound velocity, those with "auditory preference" showed differential peaks in phosphene perception whose delays after sound-offset followed the different L-sound velocity profiles. These novel findings suggest that looming signals modulate visual cortex excitability beyond sound duration possibly to support prompt identification and reaction to potentially dangerous approaching objects. The observed interindividual differences favor the idea that unlike early effects this late L-sound impact on visual cortex excitability is influenced by cross-modal attentional mechanisms rather than low-level sensory processes.
Resumo:
Testis size and sperm production are directly correlated to the total number of adult Sertoli cells (SCs). Although the establishment of an adequate number of SCs is crucial for future male fertility, the identification and characterization of the factors regulating SC survival, proliferation, and maturation remain incomplete. To investigate whether the IGF system is required for germ cell (GC) and SC development and function, we inactivated the insulin receptor (Insr), the IGF1 receptor (Igf1r), or both receptors specifically in the GC lineage or in SCs. Whereas ablation of insulin/IGF signaling appears dispensable for GCs and spermatogenesis, adult testes of mice lacking both Insr and Igf1r in SCs (SC-Insr;Igf1r) displayed a 75% reduction in testis size and daily sperm production as a result of a reduced proliferation rate of immature SCs during the late fetal and early neonatal testicular period. In addition, in vivo analyses revealed that FSH requires the insulin/IGF signaling pathway to mediate its proliferative effects on immature SCs. Collectively, these results emphasize the essential role played by growth factors of the insulin family in regulating the final number of SCs, testis size, and daily sperm output. They also indicate that the insulin/IGF signaling pathway is required for FSH-mediated SC proliferation.
Resumo:
Action representations can interact with object recognition processes. For example, so-called mirror neurons respond both when performing an action and when seeing or hearing such actions. Investigations of auditory object processing have largely focused on categorical discrimination, which begins within the initial 100 ms post-stimulus onset and subsequently engages distinct cortical networks. Whether action representations themselves contribute to auditory object recognition and the precise kinds of actions recruiting the auditory-visual mirror neuron system remain poorly understood. We applied electrical neuroimaging analyses to auditory evoked potentials (AEPs) in response to sounds of man-made objects that were further subdivided between sounds conveying a socio-functional context and typically cuing a responsive action by the listener (e.g. a ringing telephone) and those that are not linked to such a context and do not typically elicit responsive actions (e.g. notes on a piano). This distinction was validated psychophysically by a separate cohort of listeners. Beginning approximately 300 ms, responses to such context-related sounds significantly differed from context-free sounds both in the strength and topography of the electric field. This latency is >200 ms subsequent to general categorical discrimination. Additionally, such topographic differences indicate that sounds of different action sub-types engage distinct configurations of intracranial generators. Statistical analysis of source estimations identified differential activity within premotor and inferior (pre)frontal regions (Brodmann's areas (BA) 6, BA8, and BA45/46/47) in response to sounds of actions typically cuing a responsive action. We discuss our results in terms of a spatio-temporal model of auditory object processing and the interplay between semantic and action representations.
Resumo:
Mucosal candidiasis is frequent in immunocompromised HIV-infected highly active antiretroviral (HAART) naive patients or those who have failed therapy. Mucosal candidiasis is a marker of progressive immune deficiency. Because of the frequently marked and prompt immune reconstitution induced by HAART, there is no recommendation for primary antifungal prophylaxis of mucosal candidiasis in the HIV setting in Europe, although it has been evidenced as effective in the pre-HAART era. Fluconazole remains the first line of therapy for both oropharyngeal candidiasis and oesophageal candidiasis and should be preferred to itraconazole oral solution (or capsules when not available) due to fewer side effects. For patients who still present with fluconazole-refractory mucosal candidiasis, oral treatment with any other azole should be preferred based on precise Candida species identification and susceptibility testing results in addition to the optimization of HAART when feasible. For vaginal candidiasis, topical therapy is preferred.