نتایج جستجو برای: hemodynamic response function
تعداد نتایج: 2085600 فیلتر نتایج به سال:
Introduced is a general framework for performing group-level analyses of fMRI data using any basis set of two functions (i.e., the canonical hemodynamic response function and its first derivative) to model the hemodynamic response to neural activity. The approach allows for flexible implementation of physiologically based restrictions on the results. Information from both basis functions is use...
Background & objectives: Cardiopulmonary bypass often causes a stress hormonal response with subsequent changes in hemodynamic and organ perfusion. Human studies involving cardiopulmonary bypass have shown that very low doses of ketamine can attenuate inflammatory and stress markers, without adverse effects. The aim of this study was to investigate whether low dose infusion of ketamine have hem...
Today, most studies of cognitive processes using functional MRI (fMRI) experiments adopt a single-trial design. Highly flexible stimulation paradigms require new statistical models in which not only the activation amount but also the time course of the measured hemodynamic response is analyzed. Most previous approaches have been based on a linear regression context and have introduced hemodynam...
Many cognitive paradigms require self-paced responses or examine events that occur at unpredictable times. To explore whether functional MRI (fMRI) can accommodate such paradigms, a method allowing rapid, unpredictable trial pacing was developed and tested on 17 subjects using activation of the motor network as a model. Trial onset was determined solely by the subjects' self-paced responses and...
Recent research on potential applications of fMRI in the detection of concealed knowledge primarily ascribed the reported differences in hemodynamic response patterns to deception. This interpretation is challenged by the results of the present study. Participants were required to memorize probe and target items (a banknote and a playing card, each). Subsequently, these items were repeatedly pr...
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