1,721,000 research outputs found
Radiomic reliability assessed on anatomical and diffusion MRI in Autosomal Dominant Polycystic Kidney Disease (ADPKD) patient
No full textReliability of Mental Workload Index Assessed by EEG with Different Electrode Configurations and Signal Pre-Processing Pipelines
No full textBackground and Objective: Mental workload (MWL) is a relevant construct involved in all cognitively demanding activities, and its assessment is an important goal in many research fields. This paper aims at evaluating the reproducibility and sensitivity of MWL assessment from EEG signals considering the effects of different electrode configurations and pre-processing pipelines (PPPs). Methods: Thirteen young healthy adults were enrolled and were asked to perform 45 min of Simon’s task to elicit a cognitive demand. EEG data were collected using a 32-channel system with different electrode configurations (fronto-parietal; Fz and Pz; Cz) and analyzed using different PPPs, from the simplest bandpass filtering to the combination of filtering, Artifact Subspace Reconstruction (ASR) and Independent Component Analysis (ICA). The reproducibility of MWL indexes estimation and the sensitivity of their changes were assessed using Intraclass Correlation Coefficient and statistical analysis. Results: MWL assessed with different PPPs showed reliability ranging from good to very good in most of the electrode configurations (average consistency > 0.87 and average absolute agreement > 0.92). Larger fronto-parietal electrode configurations, albeit being more affected by the choice of PPPs, provide better sensitivity in the detection of MWL changes if compared to a single-electrode configuration (18 vs. 10 statistically significant differences detected, respectively). Conclusions: The most complex PPPs have been proven to ensure good reliability (>0.90) and sensitivity in all experimental conditions. In conclusion, we propose to use at least a two-electrode configuration (Fz and Pz) and complex PPPs including at least the ICA algorithm (even better including ASR) to mitigate artifacts and obtain reliable and sensitive MWL assessment during cognitive tasks
Penumbra region excitability is not enhanced acutely after cerebral ischemia in the in vitro isolated guinea pig brain
No full textEarly seizures are a frequent consequence of stroke. The main goal of the present study is to verify whether anoxic ischemia per se is able to induce early changes in excitability that may be a prelude to the generation of seizures and, ultimately, to epileptogenesis. Excitability changes in the very acute postischemic phase are here analyzed in a new model of ischemia developed in the isolated guinea pig brain preparation.Permanent bilateral occlusion of the anterior cerebral arteries (ACAs) was performed in the isolated guinea pig brain maintained in vitro by arterial perfusion. Magnetic resonance imaging and immunohistochemistry were utilized to identify the penumbra and core regions induced by ACA occlusion (ACAo). Slow potentials and evoked responses recorded in olfactory cortices were utilized to evaluate excitability changes in the acute phase after ischemia.ACAo induces a core area located in the shell of the nucleus accumbens and a region of penumbra in the underlying olfactory cortices, where characteristic slow potential shifts, but no reduction of diffusion tensor magnetic resonance (MR) signal and microtubule associated protein 2 (MAP-2) immunostaining (typical of ischemic core) was observed. Recording of responses evoked by low- and high-frequency stimulations of the lateral olfactory tract showed no excitability changes in the early hours that follow ischemia in the olfactory cortical areas supplied by ACAs.The absence of early hyperexcitability changes in an isolated whole brain model of ischemia, strongly suggests that brain anoxia per se does not contribute to the generation of early seizures. These findings support the view that blood-borne events (such as hemorrhage and inflammation) may play a major role in early postischemic seizures
Protocol assessment for quantitative 19F MRI of low concentrated compounds on a preclinical 7T MRI scanner: preliminary evaluations and results
No full textFunctional and structural correlates of magnetic resonance patterns in a new in vitro model of cerebral ischemia by transient occlusion of the medial cerebral artery.
No full textHigh Field 19F MRI: optimization of Rapid Acquisition with Relaxation Enhancement (RARE) sequences to improve the sensitivity on a preclinical 7T MRI scanner.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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