Time invariant BOLD impulse response functions for brief- and long-lasting stimuli
نویسندگان
چکیده
convolution each of the BOLD responses with a single universal transfer function, modeled BOLD signals were generated which when differenced with the measured BOLD signals showed residual signals which were smaller than the measurement uncertainty. The root mean square (RMS) of the residual signal (left number) was compared with the averaged standard deviation (SD) of the measured data (right number). In every case, the RMS of the residual was lower than the measured SD.
منابع مشابه
BOLD impulse response functions and baseline-dependent response adaptation
INTRODUCTION It is well known that the BOLD impulse response functions (IRFs) show some degree of variability – primarily represented by either a presence or absence of a delayed undershoot – across different stimuli and/or regions. However a mechanistic basis of the BOLD-IRF variability is unknown. We hypothesized that BOLD-IRFs could be different due to the system’s variable adaptive properti...
متن کاملTemporal Autocorrelation of Noise for BOLD and IRON fMRI
F. P. Leite, D. Greve, W. Vanduffel, J. B. Mandeville HST, MIT, Cambridge, MA, United States, A A Martinos Center for Biomedical Imaging, Charlestown, MA, United States Introduction IRON (Increased Relaxation for Optimized Neuroimaging) contrast has significant advantages over BOLD (Blood Oxygen Level Dependent) contrast for fMRI in animal models. IRON contrast has much better functional sensit...
متن کاملNeural and Vascular Response Nonlinearity in Human Visual Cortex
The fMRI technique typically assumes that the BOLD signal at an activated voxel results from the convolution of external stimuli with a linear time-invariant system. However, a number of previous studies have demonstrated a nonlinear stimuli-to-BOLD relationship (i.e. the BOLD nonlinearity), which may reflect a nonlinear neural response to stimuli and/or a nonlinear vascular response to neural ...
متن کاملThe nexus of renewable energy - sustainable development - environmental quality in Iran: Bayesian VAR approach
The use of renewable energy reduces environmental pollution and leads to achievement of sustainable development. The current study investigates the dynamic interrelationship between sustainable development, renewable and non-renewable energies and environment nexus by applying Bayesian vector autoregression (BVAR) and impulse response functions in Iran with an annual data frequency for the time...
متن کاملBOLD responses to stimuli: dependence on frequency, stimulus form, amplitude, and repetition rate.
A quantitative theory is developed for the relationship between stimulus and the resulting blood oxygen level-dependent (BOLD) functional MRI signal. The relationship of stimuli to neuronal activity during evoked responses is inferred from recent physiology-based quantitative modeling of evoked response potentials (ERPs). A hemodynamic model is then used to calculate the BOLD response to neuron...
متن کامل