dynamical model of hemodynamic signal transduction in fMRI. Subsequent work by Mandeville et al. (1999) provided important theoretical and empirical constraints on the form of the dynamic relationship between blood flow and volume that underpins the evolution of the fMRI signal. In this paper we combine

). The optimal spin-echo time of 40 msec was confirmed from echo-time dependency fMRI studies. The intravascular contribution was examined using a graded diffusion-weighted spin-echo echo-planar imaging technique with diffusion weighting factor (b) valuesofupto 1200 sec/mm2. Relative BOLD signal changes induced

cortex of cats using diffusion-weighted (DW) spin-echo The measurement of ADC in fMRI is generally achieved by varying the levels of diffusion weighting (usually quantified as b) and then fitting the resulting attenuated signals to a monoexponential decaying function of b. According to the intravoxel

method appeared effective in minimizing effects of the interaction between scanning noise and experimental auditory stimulation; it adds useful temporal information to the spatial resolution afforded by fMRI in studies of human auditory function, while allowing presentation of auditory stimuli on a

Abstract: The goal of this functional magnetic resonance imaging (fMRI) study was to compare the central effects of electroacupuncture at different frequencies with traditional Chinese manual acupuncture. Although not as time-tested as manual acupuncture, electroacupuncture does have the advantage

In this work, we investigated the effect of the regional variability of the hemodynamic response on the sensitivity of Granger causality (GC) analysis of functional magnetic resonance imaging (fMRI) data to neuronal causal influences. We simulated fMRI data by convolving a standard canonical

if the expected difference in responses is small and if the number of suitable stimuli is limited. Hum. Brain Mapping 20:1–12, 2003. © 2003 Wiley-Liss, Inc. Key words: event-related fMRI; repetition effects; face processing; experimental design

artefacts not accounted for by rigid body registration. These contributions give rise to temporal autocorrelation in the residuals of the fMRI signal and invalidate the statistical analysis as the errors are no longer independent. The low-frequency drift is often removed by high-pass filtering, and other

Localized changes in cortical blood oxygenation during voluntary movements were examined with functional magnetic resonance imaging (fMRI) and evaluated with a new dynamical cluster analysis (DCA) method. fMRI was performed during finger movements with eight subjects on a 1.5-T scanner using single

due to chronic pain in the brain pain matrix’s effective con-nectivity. The approach is able to deconvolve the hemody-namic response function from spontaneous neural events, i.e., in the absence of explicit onset timings, and to evaluate infor-mation transfer between two regions as a joint probability