We often close our eyes to improve perception. Recent results have shown a decrease of perception thresholds accompanied by an increase in somatosensory activity after eye closure. However, does somatosensory spatial discrimination also benefit from eye closure? We previously showed that spatial discrimination is accompanied by a reduction of somatosensory activity. Using magnetoencephalography, we analyzed the magnitude of primary somatosensory (somatosensory P50m) and primary auditory activity (auditory P50m) during a one-back discrimination task in 21 healthy volunteers. In complete darkness, participants were requested to pay attention to either the somatosensory or auditory stimulation and asked to open or close their eyes every 6.5 min. Somatosensory P50m was reduced during a task requiring the distinguishing of stimulus location changes at the distal phalanges of different fingers. The somatosensory P50m was further reduced and detection performance was higher during eyes open. A similar reduction was found for the auditory P50m during a task requiring the distinguishing of changing tones. The function of eye closure is more than controlling visual input. It might be advantageous for perception because it is an effective way to reduce interference from other modalities, but disadvantageous for spatial discrimination because it requires at least one top-down processing stage.

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Background Stenoses of the left atrial appendage (LAA) represent a common complication after incomplete surgical ligation. However, the idiopathic entity is very rare. So far, there is uncertainty about the thromboembolic risk and potential benefit for anticoagulation in these patients. We report on congenital ostial stenosis of the LAA as a secondary finding in a patient with myocardial infarction. Case summary A 56-year-old patient presented with acute heart failure secondary to STEMI and eventually progressed to cardiogenic shock. A percutaneous coronary intervention and stent placement in the first diagonal branch and in the left anterior descending artery was performed in two sessions. There was a new onset of typical atrial flutter and paroxysmal atrial fibrillation with hemodynamically relevant tachycardia. Before synchronized electrical cardioversion, we performed transesophageal echocardiography. Left atrial thrombi were ruled out. Surprisingly, we found a membranous ostial stenosis of the LAA, resulting in a bidirectional flow pattern. After 28 days of treatment in the intensive care unit the patient had full clinical recovery. Discussion Given the very rare cases of congenital LAA ostial stenosis, there is uncertainty about the thrombogenicity and a potential benefit of anticoagulation or even a percutaneous closure of the LAA. We discuss possible similarities regarding the thromboembolic risk of patients with an idiopathic narrowing of the LAA to patients with incomplete surgical ligation and patients with a device leak after percutaneous LAA closure. Congenital ostial LAA stenosis represents a clinically relevant condition and may be considered as a potential hazard for thromboembolism.