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Morgan M.,City University London | Morgan M.,Max Planck Institute for Metabolism Research
Current Biology | Year: 2015

A new experiment shows that the perceived motion path of a textured object is affected both by the path of the object and by the motion of texture within it, but that eye movements attempting to intercept the object are unaffected by the texture movement. © 2015 Elsevier Ltd All rights reserved. Source

Heiss W.-D.,Max Planck Institute for Metabolism Research
Cerebrovascular Diseases | Year: 2016

Background: Malignant middle cerebral artery infarction is a devastating condition, with up to 80% mortality in conservatively treated patients. The pathophysiology of this stroke is characterized by a large core of severe ischemia and only a relatively small rim of penumbra. Due to the fast development of irreversible morphological damage, cytotoxic edema occurs immediately in a large portion of the ischemic territory. The subsequent damage of the tight junctions leads to the breakdown of the blood brain barrier and vasogenic brain edema, resulting in space-occupying brain swelling. The progressive vasogenic edema reaches its maximum after 1 to several days and exerts a mechanical force on surrounding tissue structures leading to midline shift and transtentorial herniation and finally brain stem compression and death. Summary: Early severe neurological symptoms - hemiparesis, gaze deviation, higher cortical signs - followed by headache, vomiting, papillo edema and reduced consciousness may predict the deleterious course. Imaging supports the suspected diagnosis with hypodense changes on CT extending beyond 50% of the MCA territory. The size of the probably infarcted tissue and a midline shift on CT as well as the size of the lesion on diffusion-weighted MRI are predictive of a malignant course. Reduction of cerebral blood flow below a critical value and volume of irreversible tissue damage detected by positron emission tomography in the early hours after the stroke are indicative of progression to malignant infarction with increased intracranial pressure (ICP) and decreased tissue oxygen tension observed by multimodal neuromonitoring in the later course. Treatment options of malignant infarction include general measures to limit the extent of space-occupying edema, but these therapies have not been efficacious. Only surgical intervention with decompressive hemicraniectomy (DHC) was successful in relieving the effects of increased ICP and of the deleterious shifts of brain tissue. Several controlled clinical trials have proven the efficacy of DHC with a significant decrease in mortality and improved functional outcome. However, DHC must be performed early and with a large diameter, regardless of the age of patients, but in patients beyond 60 years, the higher likelihood of resulting severe disability should be taken into consideration. Key Messages: Malignant MCA infarction can be predicted early with a high sensitivity by neuroimaging. The early diagnosis is mandatory for DHC, which was shown to reduce mortality and improve functional outcome in several controlled clinical trials. © 2015 S. Karger AG, Basel. Source

Vossel S.,University College London | Vossel S.,Julich Research Center | Mathys C.,University College London | Mathys C.,ETH Zurich | And 4 more authors.
Journal of Neuroscience | Year: 2015

The deployment of visuospatial attention and the programming of saccades are governed by the inferred likelihood of events. In the present study, we combined computational modeling of psychophysical data with fMRI to characterize the computational and neural mechanisms underlying this flexible attentional control. Sixteen healthy human subjects performed a modified version of Posner’s location-cueing paradigm in which the percentage of cue validity varied in time and the targets required saccadic responses. Trialwise estimates of the certainty (precision) of the prediction that the target would appear at the cued location were derived from a hierarchical Bayesian model fitted to individual trialwise saccadic response speeds. Trial-specific model parameters then entered analyses of fMRI data as parametric regressors. Moreover, dynamic causal modeling (DCM) was performed to identify the most likely functional architecture of the attentional reorienting network and its modulation by (Bayes-optimal) precision-dependent attention. While the frontal eye fields (FEFs), intraparietal sulcus, and temporoparietal junction (TPJ) of both hemispheres showed higher activity on invalid relative to valid trials, reorienting responses in right FEF, TPJ, and the putamen were significantly modulated by precision-dependent attention. Our DCM results suggested that the precision of predictability underlies the attentional modulation of the coupling of TPJ with FEF and the putamen. Our results shed new light on the computational architecture and neuronal network dynamics underlying the contextsensitive deployment of visuospatial attention. © 2015 the authors. Source

Stephan K.E.,ETH Zurich | Stephan K.E.,University College London | Stephan K.E.,Max Planck Institute for Metabolism Research | Iglesias S.,ETH Zurich | And 2 more authors.
Neuron | Year: 2015

Functional neuroimaging has made fundamental contributions to our understanding of brain function. It remains challenging, however, to translate these advances into diagnostic tools for psychiatry. Promising new avenues for translation are provided by computational modeling of neuroimaging data. This article reviews contemporary frameworks for computational neuroimaging, with a focus on forward models linking unobservable brain states to measurements. These approaches-biophysical network models, generative models, and model-based fMRI analyses of neuromodulation-strive to move beyond statistical characterizations and toward mechanistic explanations of neuroimaging data. Focusing on schizophrenia as a paradigmatic spectrum disease, we review applications of these models to psychiatric questions, identify methodological challenges, and highlight trends of convergence among computational neuroimaging approaches. We conclude by outlining a translational neuromodeling strategy, highlighting the importance of openly available datasets from prospective patient studies for evaluating the clinical utility of computational models. Psychiatry lacks diagnostic tools that enable clinical predictions and treatment selection for individual patients. Computational models of neuroimaging data offer a promising new avenue. Focusing on schizophrenia, this article reviews clinical applications, methodological challenges, and future developments of computational neuroimaging. © 2015 Elsevier Inc. Source

Hoehn M.,Max Planck Institute for Metabolism Research
Georgian medical news | Year: 2015

The investigation of dynamic processes with long time profiles can profit from longitudinal noninvasive imaging modalities. In this contribution the potential and limits of in vivo imaging modalities are discussed as regards monitoring neuro-inflammation. Complementary information derived from magnetic resonance imaging (MRI), positron emission tomography (PET) and bioluminescence imaging (BLI) will be presented. Source

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