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Selecting an optimal event distribution for experimental use in event-related fMRI studies can require the generation of large numbers of event sequences with characteristics hard to control. The use of known probability distributions offers the possibility to control event timing and constrain the search space for finding optimal event sequences. We(More)
Recently, the possibility to use both magnitude and phase image sets for the statistical evaluation of fMRI has been proposed, with the prospective of increasing both statistical power and the spatial specificity. In the present work, several issues that affect the spatial and temporal stability in fMRI phase time series in the presence of physiologic noise(More)
Magnetic resonance imaging (MRI) studies have highlighted the possibility to investigate brain iron content in vivo. In this study, we combined T2* relaxometry and automatic segmentation of basal ganglia based on T1-weighted images in healthy subjects, with the aim of characterizing age related changes in volume and iron-related relaxivity values (R2*) of(More)
Many efforts have been done in order to preview the properties of the magnetic resonance (MR) signals produced by the neuronal currents using simulations. In this paper, starting with a detailed calculation of the magnetic field produced by the neuronal currents propagating over single hippocampal CA1 pyramidal neurons placed inside a cubic MR voxel of(More)
It is assumed that several neuropsychological impairments characterize the cognitive profile of individuals with developmental dyslexia (DD). Phonological and visual processing are often impaired as well as auditory processing, attention, and information processing speed. Although reports in the literature on implicit learning abilities are contradictory,(More)
Neuronal current MRI (nc-MRI) is an imaging method that directly maps magnetic field changes caused by neuronal currents with, at the same time, a high spatial and temporal resolution. A viable nc-MRI method would be of great benefit, both for the study of human brain function and for clinical applications in the field of epilepsy, especially for the(More)
With the introduction of event-related designs in fMRI, it has become crucial to optimize design efficiency and temporal filtering to detect activations at the 1st level with high sensitivity. We investigate the relevance of these issues for fMRI population studies, that is, 2nd-level analysis, for a set of event-related fMRI (er-fMRI) designs with(More)
In this study, diffusion tensor imaging (DTI) and T(2)* multiechorelaxometry were combined in 30 healthy subjects at 3T, with the aim of characterizing the spatial distribution of relaxation rates in white matter (WM). Region of interest (ROI) analysis was performed in 23 different fiber tracts automatically defined in standard space. Spearman rank analysis(More)
Simultaneous EEG-fMRI is a powerful tool to study spontaneous and evoked brain activity because of the complementary advantages of the two techniques in terms of temporal and spatial resolution. In recent years, a significant number of scientific works have been published on this subject. However, many technical problems related to the intrinsic(More)
Although the majority of fMRI studies exploit magnitude changes only, there is an increasing interest regarding the potential additive information conveyed by the phase signal. This integrated part of the complex number furnished by the MR scanners can also be used for exploring direct detection of neuronal activity and for thermography. Few studies have(More)