Accurate interpretation of functional MRI (fMRI) signals requires knowledge of the relationship between the hemodynamic response and the neuronal activity that underlies it. Here we address the question of coupling between pre- and postsynaptic neuronal activity and the hemodynamic response in rodent somatosensory (Barrel) cortex in response to single-whisker deflection. Using full-field multiw...

We present a new algorithm to estimate hemodynamic response function (HRF) and drift components of fMRI data in wavelet domain. The HRF is modeled by both parametric and nonparametric models. The functional Magnetic resonance Image (fMRI) noise is modeled as a fractional brownian motion (fBm). The HRF parameters are estimated in wavelet domain by exploiting the property that wavelet transforms ...

In functional magnetic resonance imaging (fMRI), modeling the complex link between neuronal activity and its hemodynamic response via the neurovascular coupling requires an elaborate and sensitive response model. Methods based on physiologic assumptions as well as direct, descriptive models have been proposed. The focus of this study is placed on such a direct approach that allows for a robust ...

Objective-  To evaluate kidney hemodynamic response including blood flow velocity in segmental arteries shortly after administration of various dose of saffron extract (10, 40 and 90 mg/kg).   Design- Technical assessment, experimental study.   Animals- 20 healthy male Sprague-Dawley rats.   Procedures- In this study, using a real-time pulsed doppler analysis, kidney hemodynamic response inc...

or had significant heart failure. Often the hemodynamic response to plasma volume expansion within fifteen hours after uncomplicated acute myocardial infarction is abnormal, but it is not useful in predicting prognosis. The abnormal hemodynamic response may be transient, improving during early convalescence. It represents an interaction between left ventricular compliance and function, both of ...

An understanding of the relationship between changes in neural activity and the accompanying hemodynamic response is crucial for accurate interpretation of functional brain imaging data and in particular the blood oxygen level-dependent (BOLD) fMRI signal. Much physiological research investigating this topic uses anesthetized animal preparations, and yet, the effects of anesthesia upon the neur...