Improved Activation and Hemodynamic Response Function of Olfactory fMRI Using Simultaneous Multislice with Reduced TR Acquisition

Objectives. The respiration could decrease the time synchronization between odor stimulation and data acquisition, consequently deteriorating the functional activation and hemodynamic response function (HRF) in olfactory functional magnetic resonance imaging (fMRI) with a conventional repetition time (TR). In this study, we aimed to investigate whether simultaneous multislice (SMS) technology with reduced TR could improve the blood oxygen level-dependent (BOLD) activation and optimize HRF modeling in olfactory fMRI. Methods. Sixteen young healthy subjects with normal olfaction underwent olfactory fMRI on a 3T MRI scanner using a 64 channel head coil. FMRI data were acquired using SMS acceleration at three different TRs: 3000 ms, 1000 ms, and 500 ms. Both metrics of BOLD activation (activated voxels, mean, and maximum t -scores) and the HRF modeling (response height and time to peak) were calculated in the bilateral amygdalae, hippocampi, and insulae. Results. The 500 ms and 1000 ms TRs both significantly improved the number of activated voxels, mean, and maximum t -score in the amygdalae and insulae, compared with a 3000 ms TR (all P < 0.05 ). But the increase of these metrics in the hippocampi did not reach a statistical significance (all P > 0.05 ). No significant difference in any BOLD activation metrics between TR 500 ms and 1000 ms was observed in all regions of interest (ROIs) (all P > 0.05 ). The HRF curves showed that higher response height and shorter time to peak in all ROIs were obtained at 500 ms and 1000 ms TRs compared to 3000 ms TR. TR 500 ms had a more significant effect on response height than TR 1000 ms in the amygdalae ( P = 0.017 ), and there was no significant difference in time to peak between TR 500 ms and 1000 ms in all ROIs (all P > 0.05 ). Conclusions. The fast image acquisition technique of SMS with reduced TR could significantly improve the functional activation and HRF curve in olfactory fMRI.

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Retinotopic variations of the negative blood-oxygen-level dependent hemodynamic response function in human primary visual cortex

Journal of Neurophysiology ◽

10.1152/jn.00676.2020 ◽

2021 ◽

Vol 125 (4) ◽

pp. 1045-1057 ◽

Cited By ~ 1

Author(s):

Natasha de la Rosa ◽

David Ress ◽

Amanda J. Taylor ◽

Jung Hwan Kim

Keyword(s):

Visual Cortex ◽

Response Function ◽

Complex Dynamics ◽

Hemodynamic Response ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Oxygen Level ◽

Hemodynamic Response Function ◽

Blood Oxygen Level ◽

Early Visual Cortex

We investigate dynamics of the negative hemodynamic response function (nHRF), the negative blood-oxygen-level-dependent (BOLD) response (NBR) evoked by a brief stimulus, in human early visual cortex. Here, we show that the nHRFs are not inverted versions of the corresponding pHRFs. The nHRF has complex dynamics that varied significantly with eccentricity. The results also show shift-invariant temporal linearity does not hold for the NBR.

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Nonlinear blood oxygen level-dependent responses for transient activations and deactivations in V1 — insights into the hemodynamic response function with the balloon model

Magnetic Resonance Imaging ◽

10.1016/j.mri.2008.07.017 ◽

2009 ◽

Vol 27 (4) ◽

pp. 449-459 ◽

Cited By ~ 11

Author(s):

Lin Tang ◽

Malcolm J. Avison ◽

John C. Gore

Keyword(s):

Response Function ◽

Hemodynamic Response ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Oxygen Level ◽

Hemodynamic Response Function ◽

Blood Oxygen Level

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The effect of self- vs. externally generated actions on timing, duration and amplitude of BOLD response for visual feedback processing

10.1101/2021.06.19.449116 ◽

2021 ◽

Author(s):

Eleftherios Kavroulakis ◽

Bianca M van Kemenade ◽

Ezgi B Arikan ◽

Tilo Kircher ◽

Benjamin Straube

Keyword(s):

Hemodynamic Response ◽

Blood Oxygen Level Dependent ◽

Neural Processing ◽

Hemodynamic Response Function ◽

Subcortical Structures ◽

Blood Oxygen Level ◽

Feedback Processing ◽

Variable Delays ◽

Custom Made ◽

Predictive Mechanisms

It has been widely assumed that internal forward models use efference copies to create predictions about the sensory consequences of our own actions. While these predictions had been frequently associated with reduced neural processing in sensory cortices, the timing and duration of the hemodynamic response of self-generated as opposed to externally generated movements is poorly investigated. In the present study we tested the hypothesis that predictive mechanisms for self-generated actions lead to early and shorter neural processing compared with externally generated movements. Using a first and second-order Taylor approximation in terms of the temporal (TD) and dispersion (DD) derivatives of a canonical hemodynamic response function, we investigated the timing and duration of activation for self-generated and externally generated movements using a custom-made fMRI-compatible movement device. Visual video feedback of the active and passive hand movements were presented in real time or with variable delays (0 - 417 ms). Participants had to judge, whether the feedback was delayed. We found earlier feedback processing for self-generated compared to externally generated movements in several regions including the supplementary motor area, cerebellum, subcortical structures such as the putamen and visual cortices. Shorter processing was found in areas, which show also lower blood oxygen level dependent (BOLD) amplitudes, such as the SMA, occipital and parietal cortex. Specifically, earlier activation in the putamen, of self-generated movements was associated with worse performance in detecting delays. These findings support our hypothesis, that efference copy based predictive mechanisms enable earlier processing of action feedback, as potential source for behavioral effects.

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Modeling of the Hemodynamic Responses in Block Design fMRI Studies

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2013.200 ◽

2013 ◽

Vol 34 (2) ◽

pp. 316-324 ◽

Cited By ~ 35

Author(s):

Zuyao Y Shan ◽

Margaret J Wright ◽

Paul M Thompson ◽

Katie L McMahon ◽

Gabriella G A M Blokland ◽

...

Keyword(s):

Response Function ◽

Goodness Of Fit ◽

Block Design ◽

Onset Time ◽

Hemodynamic Response ◽

Fmri Data ◽

Parameter Estimates ◽

Block Designs ◽

Hemodynamic Response Function ◽

Time To Peak

The hemodynamic response function (HRF) describes the local response of brain vasculature to functional activation. Accurate HRF modeling enables the investigation of cerebral blood flow regulation and improves our ability to interpret fMRI results. Block designs have been used extensively as fMRI paradigms because detection power is maximized; however, block designs are not optimal for HRF parameter estimation. Here we assessed the utility of block design fMRI data for HRF modeling. The trueness (relative deviation), precision (relative uncertainty), and identifiability (goodness-of-fit) of different HRF models were examined and test–retest reproducibility of HRF parameter estimates was assessed using computer simulations and fMRI data from 82 healthy young adult twins acquired on two occasions 3 to 4 months apart. The effects of systematically varying attributes of the block design paradigm were also examined. In our comparison of five HRF models, the model comprising the sum of two gamma functions with six free parameters had greatest parameter accuracy and identifiability. Hemodynamic response function height and time to peak were highly reproducible between studies and width was moderately reproducible but the reproducibility of onset time was low. This study established the feasibility and test–retest reliability of estimating HRF parameters using data from block design fMRI studies.

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Hemodynamic response function in resting brain: disambiguating neural events and autonomic effects

10.1101/028514 ◽

2015 ◽

Cited By ~ 1

Author(s):

Guorong Wu ◽

Daniele Marinazzo

Keyword(s):

Point Process ◽

Resting State ◽

Process Analysis ◽

Cardiac Activity ◽

Hemodynamic Response ◽

Blood Oxygen Level Dependent ◽

Blood Oxygen ◽

Bold Signal ◽

Hemodynamic Response Function ◽

Blood Oxygen Level

It has been shown that resting state brain dynamics can be characterized by looking at sparse blood-oxygen-level dependent (BOLD) events, which can be retrieved by point process analysis. Cardiac activity can also induce changes in the BOLD signal, thus affect both the number of these events and the mapping between neural events and BOLD signal, namely the hemodynamic response. To isolate neural activity and autonomic effects, we compare the resting state hemodynamic response retrieved by means of a point process analysis with and without deconvolving the cardiac fluctuations. Brainstem and the surrounding cortical area (such as precuneus, insula etc.) are found to be significantly affected by cardiac pulses. Methodological and physiological implications are then discussed.

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A novel method of quantifying hemodynamic delays to improve hemodynamic response, and CVR estimates in CO2 challenge fMRI

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x20978582 ◽

2021 ◽

pp. 0271678X2097858

Author(s):

Jinxia (Fiona) Yao ◽

Ho-Ching (Shawn) Yang ◽

James H Wang ◽

Zhenhu Liang ◽

Thomas M Talavage ◽

...

Keyword(s):

Arrival Time ◽

Stress Test ◽

Low Frequency ◽

Hemodynamic Response ◽

Blood Oxygen Level Dependent ◽

Cerebrovascular Reactivity ◽

Bold Signal ◽

Hemodynamic Response Function ◽

Carbon Dioxide Co2 ◽

Co2 Challenge

Elevated carbon dioxide (CO2) in breathing air is widely used as a vasoactive stimulus to assess cerebrovascular functions under hypercapnia (i.e., “stress test” for the brain). Blood-oxygen-level-dependent (BOLD) is a contrast mechanism used in functional magnetic resonance imaging (fMRI). BOLD is used to study CO2-induced cerebrovascular reactivity (CVR), which is defined as the voxel-wise percentage BOLD signal change per mmHg change in the arterial partial pressure of CO2 (PaCO2). Besides the CVR, two additional important parameters reflecting the cerebrovascular functions are the arrival time of arterial CO2 at each voxel, and the waveform of the local BOLD signal. In this study, we developed a novel analytical method to accurately calculate the arrival time of elevated CO2 at each voxel using the systemic low frequency oscillations (sLFO: 0.01-0.1 Hz) extracted from the CO2 challenge data. In addition, 26 candidate hemodynamic response functions (HRF) were used to quantitatively describe the temporal brain reactions to a CO2 stimulus. We demonstrated that our approach improved the traditional method by allowing us to accurately map three perfusion-related parameters: the relative arrival time of blood, the hemodynamic response function, and CVR during a CO2 challenge.

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Detecting the hemodynamic response function in resting state fMRI: methodology and applications

Frontiers in Neuroinformatics ◽

10.3389/conf.fninf.2015.19.00004 ◽

2015 ◽

Vol 9 ◽

Author(s):

Wu Guorong ◽

Marinazzo Daniele

Keyword(s):

Response Function ◽

Resting State ◽

Resting State Fmri ◽

Hemodynamic Response ◽

Hemodynamic Response Function

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Bayesian estimation of the hemodynamic response function in functional MRI

10.1063/1.1477050 ◽

2002 ◽

Cited By ~ 10

Author(s):

G. Marrelec

Keyword(s):

Bayesian Estimation ◽

Functional Mri ◽

Response Function ◽

Hemodynamic Response ◽

Hemodynamic Response Function

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The brain’s hemodynamic response function rapidly changes under acute psychosocial stress in association with genetic and endocrine stress response markers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1804340115 ◽

2018 ◽

Vol 115 (43) ◽

pp. E10206-E10215 ◽

Cited By ~ 17

Author(s):

Immanuel G. Elbau ◽

Benedikt Brücklmeier ◽

Manfred Uhr ◽

Janine Arloth ◽

Darina Czamara ◽

...

Keyword(s):

Stress Response ◽

Response Function ◽

Genetic Variants ◽

Psychosocial Stress ◽

Acute Stress ◽

Physiological Stress ◽

Hemodynamic Response ◽

Hemodynamic Response Function ◽

Ample Evidence ◽

Acute Psychosocial Stress

Ample evidence links dysregulation of the stress response to the risk for psychiatric disorders. However, we lack an integrated understanding of mechanisms that are adaptive during the acute stress response but potentially pathogenic when dysregulated. One mechanistic link emerging from rodent studies is the interaction between stress effectors and neurovascular coupling, a process that adjusts cerebral blood flow according to local metabolic demands. Here, using task-related fMRI, we show that acute psychosocial stress rapidly impacts the peak latency of the hemodynamic response function (HRF-PL) in temporal, insular, and prefrontal regions in two independent cohorts of healthy humans. These latency effects occurred in the absence of amplitude effects and were moderated by regulatory genetic variants of KCNJ2, a known mediator of the effect of stress on vascular responsivity. Further, hippocampal HRF-PL correlated with both cortisol response and genetic variants that influence the transcriptional response to stress hormones and are associated with risk for major depression. We conclude that acute stress modulates hemodynamic response properties as part of the physiological stress response and suggest that HRF indices could serve as endophenotype of stress-related disorders.

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