Spontaneous dissection of the external iliac artery due to fibromuscular dysplasia. A case of spontaneous dissection of the external iliac artery due to fibromuscular dysplasia is presented. In a 45-year-old man with a history of sudden onset of intermittent claudication a dissection of the right external iliac artery was found by duplex ultrasound. The patient, who was first treated with conservative therapy, subsequently required operative treatment because of further progression of the dissection. Considering the age of the patient a retrograde thrombendarterectomy manoeuver over guide wire was performed. Angiographic control at the end of operation demonstrated a good reconstructive result without any changes in the right common iliac artery and the aorta. Histopathological examination of the removed material showed fibromuscular dysplasia of the media. In the postoperative course the patient was clinically asymptomatic with ankle/brachial pressure indices of 1.0 on both legs. But shortly after discharge the intermittent claudication in the right leg recurred. Angiography and duplex ultrasound revealed focal stenosis of the right common iliac artery as well as retrograde dissection of the right common iliac artery extending into the distal aorta. Conservative therapy was recommended to the patient by the local hospital and no further progression of clinical and duplex findings within the last six months was found.

Optimal mental workload plays a key role in driving performance. Thus, driver-assisting systems that automatically adapt to a drivers current mental workload via brain–computer interfacing might greatly contribute to traffic safety. To design economic brain computer interfaces that do not compromise driver comfort, it is necessary to identify brain areas that are most sensitive to mental workload changes. In this study, we used functional near-infrared spectroscopy and subjective ratings to measure mental workload in two virtual driving environments with distinct demands. We found that demanding city environments induced both higher subjective workload ratings as well as higher bilateral middle frontal gyrus activation than less demanding country environments. A further analysis with higher spatial resolution revealed a center of activation in the right anterior dorsolateral prefrontal cortex. The area is highly involved in spatial working memory processing. Thus, a main component of drivers’ mental workload in complex surroundings might stem from the fact that large amounts of spatial information about the course of the road as well as other road users has to constantly be upheld, processed and updated. We propose that the right middle frontal gyrus might be a suitable region for the application of powerful small-area brain computer interfaces.

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Execution of two independent actions in quick succession results in transient binding of these two actions. Subsequent repetition of any of these actions automatically retrieves the other. This process is probably fundamental for developing complex action sequences. However, rigid bindings between two actions are not always adaptive. Sometimes, it is necessary to repeat only one of the two previously executed actions. In such situations, stored action sequences must be disassembled, for the sake of flexibility. Exact mechanisms that allow for such an active unbinding of actions remain largely unknown, but it stands to reason, that some form of prefrontal executive control is necessary. Building on prior neuronal research that explored other forms of binding (e.g. between distractors and responses and abstract representations and responses), we explored middle and superior frontal correlates of -response binding in a sequential classification task with functional near-infrared spectroscopy. We found that anterior dorsolateral prefrontal cortex activity varied as a function of response–repetition condition. Activity in the right anterior dorsolateral prefrontal cortex correlated with changes in reaction times due to response–response binding. Our results indicate that the right anterior dorsolateral prefrontal cortex dismantles bindings between consecutive actions, whenever such bindings interfere with current action goals.

Abstract. The GPS radio occultation (RO) technique is used to study sporadic E (ES) layer plasma irregularities of the Earth’s ionosphere on a global scale using GPS signal-to-noise ratio (SNR) profiles from the COSMIC/FORMOSAT-3 satellite. The maximum deviation from the mean SNR can be attributed to the height of the ES layer. ES are generally accepted to be produced by ion convergence due to vertical wind shear in the presence of a horizontal component of the Earth magnetic field, while the wind shear is provided mainly by solar tides. Here we present analyses of quarterdiurnal (QDT) signatures in ES occurrence rates. We find from a local comparison with mesosphere/lower thermosphere wind shear obtained with a meteor radar at Collm (51:3°N, 13:0°E), that the phases of the QDT in ES agree well with those of negative wind shear for all seasons except for summer, when the QDT amplitudes are small. We also compare the global QDT ES signal with numerical model results. The global distribution of ES occurrence rates qualitatively agrees with the modeled zonal wind shears. The results indicate that zonal wind shear is indeed an important driving mechanism for the QDT seen in ES.