The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The poor SNR of fMRI data requires that many repetitive trials be performed during an event-related experiment to obtain statistically significant levels of inferred brain activity. This is costly in terms of scanner time, necessitates that subjects perform the behavioural task(s) for long durations which may induce fatigue, and vastly increases the amount of data generated. In this paper, we present...
Blood oxygenation level dependent (BOLD) functional MRI and near infrared optical tomography have been widely used to investigate hemodynamic responses to functional stimulation in the human brain. In this paper, we present a complete methodology for integrating the two imaging modalities to study the underlying physiological mechanism of the hemodynamic response in primary visual cortex. Using a...
The goal of our research is try to explain the electrophysiological mechanisms of alternation in T-wave of ECG in ultrahigh static magnetic field (SMF). The magneto-hydrodynamics model study shows that ultrahigh SMF can induce reduction in the volume flow rate of the blood in human aorta more than 10%, thus may lead to anoxia condition of acute ischemia. Using an ionic-based theoretical model of the...
The recording of EEG signals during fMRI scanning is now technically feasible and safe. However, artifacts relating to pulsatile blood flow (the ballistocardiogram) may still be prominently present in EEG data recorded in the MRI magnet. The application of independent component analysis (ICA) in order to reduce these artifacts off-line was investigated in three different types of EEG, one normal visually...
This paper presents the identification and the study of the impact of a real-time MRI-based propulsion and tracking system constraints on the step response using a discrete PID controller. A simplified model for such a system accounts for these constraints such as the time delay, the sampling period, and the blood velocity. This application is intended for minimally invasive operations within the...
Perfusion normally refers to the delivery of blood at the level of capillaries. Hemodynamic perfusion magnetic resonance (MR) imaging has been used in clinics for a series of applications including tumor characterization (histological type diagnosis and grading), diagnosis and the follow up of stroke, and several other disorders. For this study a platform to investigate the theoretical basis of perfusion...
In the last decade, the possibility to noninvasively estimate cortical activity and connectivity has been highlighted by the application of the techniques known as high resolution EEG. These techniques include a subject's multi-compartment head model (scalp, skull, dura mater, cortex) constructed from individual magnetic resonance images, multi-dipole source model, and regularized linear inverse source...
A nonlinear canonical correlation analysis (CCA) for detecting neural activation in fMRI data is proposed in this paper. We use the BOLD response based on the HDR models with various parameters as reference signals. Instead of characterizing the relationship between the paradigm and time series using the oversimplified linear model, we employ the kernel trick that maps the intensities of the voxels...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.