نتایج جستجو برای: physiological noise

تعداد نتایج: 450799  

Journal: :NeuroImage 2011
Javier Gonzalez-Castillo Vinai Roopchansingh Peter A. Bandettini Jerzy Bodurka

This work addresses the choice of imaging flip angle in blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI). When noise of physiological origin becomes the dominant noise source in fMRI timeseries, it causes a nonlinear dependence of the temporal signal-to-noise ratio (TSNR) versus signal-to-noise ratio (SNR) that can be exploited to perform BOLD fMRI at angles...

Introduction: Increasing women’s participation in the labor market is one of the most important social phenomena in the world. Currently, the number of pregnant mothers working in industries in the developing countries is significant; therefore, there are always issues related to occupational hazards and pregnancy health. This study has analyzed articles that examined the complications of...

2017
Xiang Meng Helena Firczuk Paola Pietroni Richard Westbrook Estelle Dacheux Pedro Mendes John E.G. McCarthy

Gene expression noise influences organism evolution and fitness. The mechanisms determining the relationship between stochasticity and the functional role of translation machinery components are critical to viability. eIF4G is an essential translation factor that exerts strong control over protein synthesis. We observe an asymmetric, approximately bell-shaped, relationship between the average i...

Journal: :Journal of neurophysiology 2001
W C Stacey D M Durand

Stochastic resonance (SR) is a phenomenon whereby the detection of a low-level signal is enhanced in a nonlinear system by the introduction of noise. Studies of the effects of SR in neurons have suggested that noise could play a prominent role in improving detection of small signals. Most experimental SR research has focused on the role of noise in sensory neurons using physiological stimuli. C...

2011
Chloe Hutton Oliver Josephs Jörg Stadler Eric Featherstone Alphonso Reid Oliver Speck Johannes Bernarding Nikolaus Weiskopf

Cognitive neuroimaging studies typically require fast whole brain image acquisition with maximal sensitivity to small BOLD signal changes. To increase the sensitivity, higher field strengths are often employed, since they provide an increased image signal-to-noise ratio (SNR). However, as image SNR increases, the relative contribution of physiological noise to the total time series noise will b...

Journal: :Magnetic resonance in medicine 2017
Olivier Reynaud João Jorge Rolf Gruetter José P Marques Wietske van der Zwaag

PURPOSE Physiological noise often dominates the blood-oxygen level-dependent (BOLD) signal fluctuations in high-field functional MRI (fMRI) data. Therefore, to optimize fMRI protocols, it becomes crucial to investigate how physiological signal fluctuations impact various acquisition and reconstruction schemes at different acquisition speeds. In particular, further differences can arise between ...

Journal: :NeuroImage 2011
Timothy D. Verstynen Vibhas Deshpande

The BOLD signal not only reflects changes in local neural activity, but also exhibits variability from physiological processes like cardiac rhythms and breathing. We investigated how both of these physiological sources are reflected in the pulse oximetry (PO) signal, a direct measure of blood oxygenation, and how this information can be used to account for different types of noise in the BOLD r...

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