7 resultados para State organization

em Université de Lausanne, Switzerland


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The transition from wakefulness to sleep represents the most conspicuous change in behavior and the level of consciousness occurring in the healthy brain. It is accompanied by similarly conspicuous changes in neural dynamics, traditionally exemplified by the change from "desynchronized" electroencephalogram activity in wake to globally synchronized slow wave activity of early sleep. However, unit and local field recordings indicate that the transition is more gradual than it might appear: On one hand, local slow waves already appear during wake; on the other hand, slow sleep waves are only rarely global. Studies with functional magnetic resonance imaging also reveal changes in resting-state functional connectivity (FC) between wake and slow wave sleep. However, it remains unclear how resting-state networks may change during this transition period. Here, we employ large-scale modeling of the human cortico-cortical anatomical connectivity to evaluate changes in resting-state FC when the model "falls asleep" due to the progressive decrease in arousal-promoting neuromodulation. When cholinergic neuromodulation is parametrically decreased, local slow waves appear, while the overall organization of resting-state networks does not change. Furthermore, we show that these local slow waves are structured macroscopically in networks that resemble the resting-state networks. In contrast, when the neuromodulator decrease further to very low levels, slow waves become global and resting-state networks merge into a single undifferentiated, broadly synchronized network.

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In natural conditions, basidiomycete ectomycorrhizal fungi such as Laccaria bicolor are typically in the dikaryotic state when forming symbioses with trees, meaning that two genetically different individuals have to fuse or 'mate'. Nevertheless, nothing is known about the molecular mechanisms of mating in these ecologically important fungi. Here, advantage was taken of the first sequenced genome of the ectomycorrhizal fungus, Laccaria bicolor, to determine the genes that govern the establishment of cell-type identity and orchestrate mating. The L. bicolor mating type loci were identified through genomic screening. The evolutionary history of the genomic regions that contained them was determined by genome-wide comparison of L. bicolor sequences with those of known tetrapolar and bipolar basidiomycete species, and by phylogenetic reconstruction of gene family history. It is shown that the genes of the two mating type loci, A and B, are conserved across the Agaricales, but they are contained in regions of the genome with different evolutionary histories. The A locus is in a region where the gene order is under strong selection across the Agaricales. By contrast, the B locus is in a region where the gene order is likely under a low selection pressure but where gene duplication, translocation and transposon insertion are frequent.

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The human brain displays heterogeneous organization in both structure and function. Here we develop a method to characterize brain regions and networks in terms of information-theoretic measures. We look at how these measures scale when larger spatial regions as well as larger connectome sub-networks are considered. This framework is applied to human brain fMRI recordings of resting-state activity and DSI-inferred structural connectivity. We find that strong functional coupling across large spatial distances distinguishes functional hubs from unimodal low-level areas, and that this long-range functional coupling correlates with structural long-range efficiency on the connectome. We also find a set of connectome regions that are both internally integrated and coupled to the rest of the brain, and which resemble previously reported resting-state networks. Finally, we argue that information-theoretic measures are useful for characterizing the functional organization of the brain at multiple scales.

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The state of Vaud model of the pre-hospital chain of survival is an example of an efficient way to deal with pre-hospital emergencies. It revolves around a centrally located dispatch center managing emergencies according to specific key words, allowing dispatchers to send out resources among which we find general practitioners, ambulances, physician staffed fast response cars or physician staffed helicopters and specific equipment. The Vaud pre-hospital chain of survival has been tailored according to geographical, demographical and political necessities. It undergoes constant reassessment and needs continuous adaptations to the ever changing demographics and epidemiology of pre-hospital medicine.

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BACKGROUND: Predicting outcome of breast cancer (BC) patients based on sentinel lymph node (SLN) status without axillary lymph node dissection (ALND) is an area of uncertainty. It influences the decision-making for regional nodal irradiation (RNI). The aim of the NORA (NOdal RAdiotherapy) survey was to examine the patterns of RNI. METHODS: A web-questionnaire, including several clinical scenarios, was distributed to 88 EORTC-affiliated centers. Responses were received between July 2013 and January 2014. RESULTS: A total of 84 responses were analyzed. While three-dimensional (3D) radiotherapy (RT) planning is carried out in 81 (96%) centers, nodal areas are delineated in only 51 (61%) centers. Only 14 (17%) centers routinely link internal mammary chain (IMC) and supraclavicular node (SCN) RT indications. In patients undergoing total mastectomy (TM) with ALND, SCN-RT is recommend by 5 (6%), 53 (63%) and 51 (61%) centers for patients with pN0(i+), pN(mi) and pN1, respectively. Extra-capsular extension (ECE) is the main factor influencing decision-making RNI after breast conserving surgery (BCS) and TM. After primary systemic therapy (PST), 49 (58%) centers take into account nodal fibrotic changes in ypN0 patients for RNI indications. In ypN0 patients with inner/central tumors, 23 (27%) centers indicate SCN-RT and IMC-RT. In ypN1 patients, SCN-RT is delivered by less than half of the centers in patients with ypN(i+) and ypN(mi). Twenty-one (25%) of the centers recommend ALN-RT in patients with ypN(mi) or 1-2N+ after ALND. Seventy-five (90%) centers state that age is not considered a limiting factor for RNI. CONCLUSION: The NORA survey is unique in evaluating the impact of SLNB/ALND status on adjuvant RNI decision-making and volumes after BCS/TM with or without PST. ALN-RT is often indicated in pN1 patients, particularly in the case of ECE. Besides the ongoing NSABP-B51/RTOG and ALLIANCE trials, NORA could help to design future specific RNI trials in the SLNB era without ALND in patients receiving or not PST.