scholarly journals Statistical Power or More Precise Insights into Neuro-Temporal Dynamics? Assessing the Benefits of Rapid Temporal Sampling in fMRI

2021 ◽  
Author(s):  
Logan T Dowdle ◽  
Geoffrey Ghose ◽  
Kamil Ugurbil ◽  
Essa Yacoub ◽  
Luca Vizioli
Keyword(s):  
Statistical Power ◽  
Temporal Dynamics ◽  
Blood Oxygen Level Dependent ◽  
Neuronal Firing ◽  
Blood Oxygen Level ◽  
Non Invasive ◽  
Temporal Sampling ◽  
Simple Question ◽  
Technological Developments ◽  
Human Neuroimaging

Functional magnetic resonance imaging (fMRI), a non-invasive and widely used human neuroimaging method, is most known for its spatial precision. However, there is a growing interest in its temporal sensitivity. This is despite the temporal blurring of neuronal events by the blood oxygen level dependent (BOLD) signal, the peak of which lags neuronal firing by 4 to 6 seconds. Given this, the goal of this review is to answer a seemingly simple question - "What are the benefits of increased temporal sampling for fMRI?". To answer this, we have combined fMRI data collected at multiple temporal scales, from 323 to 1000 milliseconds, with a review of both historical and contemporary temporal literature. After a brief discussion of technological developments that have rekindled interest in temporal research, we next consider the potential statistical and methodological benefits. Most importantly, we explore how fast fMRI can uncover previously unobserved neuro-temporal dynamics - effects that are entirely missed when sampling at conventional 1 to 2 second rates. With the intrinsic link between space and time in fMRI, this temporal renaissance also delivers improvements in spatial precision. Far from producing only statistical gains, the array of benefits suggest that the continued temporal work is worth the effort.

scholarly journals Levels of biological plausibility

2020 ◽  
Vol 376 (1815) ◽  
pp. 20190632
Author(s):  
Bradley C. Love
Keyword(s):  
Model Selection ◽  
Functional Neuroimaging ◽  
Scientific Progress ◽  
Blood Oxygen Level Dependent ◽  
Levels Of Analysis ◽  
Biological Plausibility ◽  
Blood Oxygen Level ◽  
Selection Procedures ◽  
Non Invasive ◽  
The Relationship

Notions of mechanism, emergence, reduction and explanation are all tied to levels of analysis. I cover the relationship between lower and higher levels, suggest a level of mechanism approach for neuroscience in which the components of a mechanism can themselves be further decomposed and argue that scientists' goals are best realized by focusing on pragmatic concerns rather than on metaphysical claims about what is ‘real'. Inexplicably, neuroscientists are enchanted by both reduction and emergence. A fascination with reduction is misplaced given that theory is neither sufficiently developed nor formal to allow it, whereas metaphysical claims of emergence bring physicalism into question. Moreover, neuroscience's existence as a discipline is owed to higher-level concepts that prove useful in practice. Claims of biological plausibility are shown to be incoherent from a level of mechanism view and more generally are vacuous. Instead, the relevant findings to address should be specified so that model selection procedures can adjudicate between competing accounts. Model selection can help reduce theoretical confusions and direct empirical investigations. Although measures themselves, such as behaviour, blood-oxygen-level-dependent (BOLD) and single-unit recordings, are not levels of analysis, like levels, no measure is fundamental and understanding how measures relate can hasten scientific progress. This article is part of the theme issue ‘Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.

scholarly journals A Model of the Dynamic Relationship between Blood Flow and Volume Changes during Brain Activation

2004 ◽  
Vol 24 (12) ◽  
pp. 1382-1392 ◽  
Author(s):  
Yazhuo Kong ◽  
Ying Zheng ◽  
David Johnston ◽  
John Martindale ◽  
Myles Jones ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Volume ◽  
Temporal Dynamics ◽  
Blood Oxygen Level Dependent ◽  
Extended Model ◽  
Biophysical Modeling ◽  
Blood Oxygen Level ◽  
Windkessel Model ◽  
Dynamic Relationship ◽  
Dependent Signal

The temporal relationship between changes in cerebral blood flow (CBF) and cerebral blood volume (CBV) is important in the biophysical modeling and interpretation of the hemodynamic response to activation, particularly in the context of magnetic resonance imaging and the blood oxygen level–dependent signal. Grubb et al. (1974) measured the steady state relationship between changes in CBV and CBF after hypercapnic challenge. The relationship CBVαCBFΦ has been used extensively in the literature. Two similar models, the Balloon ( Buxton et al., 1998 ) and the Windkessel ( Mandeville et al., 1999 ), have been proposed to describe the temporal dynamics of changes in CBV with respect to changes in CBF. In this study, a dynamic model extending the Windkessel model by incorporating delayed compliance is presented. The extended model is better able to capture the dynamics of CBV changes after changes in CBF, particularly in the return-to-baseline stages of the response.

scholarly journals Cortical Depth-Dependent Temporal Dynamics of the BOLD Response in the Human Brain

2011 ◽  
Vol 31 (10) ◽  
pp. 1999-2008 ◽  
Author(s):  
Jeroen CW Siero ◽  
Natalia Petridou ◽  
Hans Hoogduin ◽  
Peter R Luijten ◽  
Nick F Ramsey
Keyword(s):  
Human Brain ◽  
Gray Matter ◽  
Animal Studies ◽  
Temporal Dynamics ◽  
Onset Time ◽  
Neurovascular Coupling ◽  
Blood Oxygen Level Dependent ◽  
Peak Time ◽  
Blood Oxygen Level ◽  
Coupling Mechanisms

Recent animal studies at high field have shown that blood oxygen level-dependent (BOLD) contrast can be specific to the laminar vascular architecture of the cortex, by differences in its temporal dynamics in reference to cortical depth. In this study, we characterize the temporal dynamics of the hemodynamic response (HDR) across cortical depth in the human primary motor and visual cortex, at 7T and using very short stimuli and with high spatial and temporal resolution. We find that the shape and temporal dynamics of the HDR changed in an orderly manner across cortical depth. Compared with the pial vasculature, HDRs in deeper gray matter are significantly faster in onset time (by ∼ 0.5 second) and peak time (∼2 seconds), and are narrower (by ∼1 second) and with smaller amplitude, in line with the known vascular organization across cortical depth and the transit of deoxygenated blood through the vasculature. The width of the HDR in deeper gray matter was as short as 2.1 seconds, indicating that neurovascular coupling takes place at a shorter timescale than previously reported in the human brain. These findings open the possibility to probe layer-specific hemodynamics and neurovascular coupling mechanisms in human gray matter.

scholarly journals Relationship Between Changes in the Temporal Dynamics of the Blood-Oxygen-Level-Dependent Signal and Hypoperfusion in Acute Ischemic Stroke

Stroke ◽  
2017 ◽  
Vol 48 (4) ◽  
pp. 925-931 ◽  
Author(s):  
Ahmed A. Khalil ◽  
Ann-Christin Ostwaldt ◽  
Till Nierhaus ◽  
Ramanan Ganeshan ◽  
Heinrich J. Audebert ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Temporal Dynamics ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Dependent Signal

scholarly journals Many hats: intratrial and reward level-dependent BOLD activity in the striatum and premotor cortex

2013 ◽  
Vol 110 (7) ◽  
pp. 1689-1702 ◽  
Author(s):  
Erik J. Peterson ◽  
Carol A. Seger
Keyword(s):  
Ventral Striatum ◽  
Premotor Cortex ◽  
Learning Task ◽  
Blood Oxygen Level Dependent ◽  
Reward Processing ◽  
Unique Contribution ◽  
Blood Oxygen Level ◽  
Visuomotor Learning ◽  
Cell Recording ◽  
Human Neuroimaging

Human functional magnetic resonance imaging (fMRI) studies, as well as lesion, drug, and single-cell recording studies in animals, suggest that the striatum plays a key role in associating sensory events with rewarding actions, both by facilitating reward processing and prediction (i.e., reinforcement learning) and by biasing and later updating action selection. Previous human neuroimaging research has failed to dissociate striatal activity associated with reward, stimulus, and response processing, and previous electrophysiological research in nonhuman animals has typically only examined single striatal subregions. Overcoming both these limitations, we isolated blood oxygen level-dependent (BOLD) signal associated with four intratrial processes (stimulus, preparation of response, response, and feedback) in a visuomotor learning task and examined activity associated with each within four striatal subregions (ventral striatum, putamen, head of the caudate nucleus, and body of the caudate) and the lateral premotor cortex. Overall, the striatum and lateral premotor cortex were recruited during all trial components, confirming their importance in all aspects of visuomotor learning. However, the caudate was most active at stimulus and feedback, whereas the putamen peaked in activity at response. Activation in the lateral premotor cortex was, surprisingly, strongest during stimulus and following response as feedback approached. Activity was additionally examined at three reward magnitudes. Reward magnitude affected neural activity only during stimulus in the caudate, putamen, and premotor cortex, whereas the ventral striatum showed reward sensitivity during both stimulus and feedback. Collectively, these results indicate that each striatal region makes a unique contribution to visuomotor learning through functions performed at different points within single trials.

scholarly journals Statistical power or more precise insights into neuro-temporal dynamics? Assessing the benefits of rapid temporal sampling in fMRI

2021 ◽  
pp. 102171
Author(s):  
Logan T. Dowdle ◽  
Geoffrey Ghose ◽  
Clark C.C. Chen ◽  
Kamil Ugurbil ◽  
Essa Yacoub ◽  
...  
Keyword(s):  
Statistical Power ◽  
Temporal Dynamics ◽  
Temporal Sampling

scholarly journals Evaluation of Renal Tissue Oxygenation Using Blood Oxygen Level-Dependent Magnetic Resonance Imaging in Chronic Kidney Disease

2021 ◽  
pp. 1-11
Author(s):  
Fen Chen ◽  
Han Yan ◽  
Fan Yang ◽  
Li Cheng ◽  
Siwei Zhang ◽  
...  
Keyword(s):  
Renal Function ◽  
Tissue Oxygenation ◽  
Blood Oxygen Level Dependent ◽  
Renal Tissue ◽  
Selection Method ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
Bold Mri ◽  
Function Group ◽  
Renal Function Group

<b><i>Background:</i></b> Blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) has been widely used to assess renal oxygenation changes in different kidney diseases in recent years. This study was designed to evaluate and compare renal tissue oxygenation using 2 BOLD-MRI analysis methods, namely, the regional and whole-kidney region of interest (ROI) selection methods. <b><i>Methods:</i></b> The study ended up with 10 healthy controls and 40 chronic kidney disease (CKD) patients without dialysis. Their renal BOLD-MRI data were analyzed using whole-kidney ROI selection method and compared with regional ROI selection method. <b><i>Results:</i></b> We found the cortical, medullary, and whole-kidney R2* values were significantly higher in CKD patients than those in controls. Compared with the regional ROI selection method, the whole-kidney ROI selection method yielded higher cortical R2* values in both controls and CKD patients. The whole-kidney R2* values of deteriorating renal function group were significantly higher than those in stable renal function group. <b><i>Conclusions:</i></b> Cortical and medullary oxygenation was decreased significantly in CKD patients compared with the healthy controls, particularly in the medulla. The whole-kidney R2* values were positively correlated with kidney function and inversely correlated with the estimated glomerular filtration rate and effective renal plasma flow. Whole-Kidney R2* value might effectively predict the progression of renal function in patients with CKD.

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