The arousal-biased competition model predicts that arousal increases the gain on neural competition between stimuli representations. Thus, the model predicts that arousal simultaneously enhances processing of salient stimuli and impairs processing of relatively less-salient stimuli. We tested this model with a simple dot-probe task. On each trial, participants were simultaneously exposed to one face image as a salient cue stimulus and one place image as a non-salient stimulus. A border around the face cue location further increased its bottom-up saliency. Before these visual stimuli were shown, one of two tones played: one that predicted a shock (increasing arousal) or one that did not. An arousal-by-saliency interaction in category-specific brain regions (fusiform face area for salient faces and parahippocampal place area for non-salient places) indicated that brain activation associated with processing the salient stimulus was enhanced under arousal whereas activation associated with processing the non-salient stimulus was suppressed under arousal. This is the first functional magnetic resonance imaging study to demonstrate that arousal can enhance information processing for prioritized stimuli while simultaneously impairing processing of non-prioritized stimuli. Thus, it goes beyond previous research to show that arousal does not uniformly enhance perceptual processing, but instead does so selectively in ways that optimizes attention to highly salient stimuli.
Shoulder arthroscopy has been shown to be the procedure of choice for many diagnostic and therapeutic interventions. Neuropraxia of the great auricular nerve (GAN) is an uncommon complication of shoulder surgery, with the patient in the beach chair position. We report a case of great auricular neuropraxia associated with direct compression by a horseshoe headrest, used in routine positioning for uncomplicated shoulder surgery. In this case, an arthroscopic approach was taken, under regional anesthesia with sedation in the beach chair position. The GAN, a superficial branch of the cervical plexus, is vulnerable to neuropraxia due to its superficial anatomical location. We recommend that for the procedures of the beach chair position, the auricle be protected and covered with cotton and gauze to avoid direct compression and the position of the head and neck be checked and corrected frequently.
Coronary artery disease is commonly characterized by atherosclerotic obstruction of vessels responsible for providing adequate blood supply to the myocardium. Disruption of atheromatous plaques can promote thrombosis, significant reductions in cardiac perfusion, and devastating acute (i.e, death) or chronic (i.e., congestive heart failure) consequences. Minimally invasive, catheter-based techniques have been implemented throughout the past three decades and include balloon angioplasty and stent implantation, to alleviate occlusive plaque burden in coronary vessels. Yet, these techniques have not come without complication, namely the tendency for vessels to re-occlude, or undergo restenosis. This manifestation is characterized by acute physical and longer-lasting cellular/biochemical components. To maximize clinical effectiveness, researchers and clinicians have exploited recognition that use of a rigid bare metal stent bound to a drug-bearing polymer, or so-called drug-eluting stent (DES), is best to combat the mechanical and biological contributors to restenosis. In this report, we review restenosis factors in detail, the corresponding rationale for drug choice for DES, and the results of trials conducted with such DES agents. Particular emphasis is given to paclitaxel, a natural compound included on a first-generation DES (Taxus® Express(2)®) made available for clinical use by Boston Scientific Corporation. We use paclitaxel as a model to illustrate alternatives for drug delivery to coronary vessels, broad concerns about DES use in the context of disease backgrounds, such as diabetes, and suggestions related to the continuing evolution of DES.
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