scholarly journals Perception affects the brain's metabolic response to sensory stimulation

2021 ◽  
Author(s):  
Mauro DiNuzzo ◽  
Silvia Mangia ◽  
Marta Moraschi ◽  
Daniele Mascali ◽  
Gisela E. Hagberg ◽  
...  
Keyword(s):  
Metabolic Response ◽  
Visual Stimulation ◽  
Aerobic Glycolysis ◽  
Sensory Stimulation ◽  
Blood Oxygenation ◽  
Bold Fmri ◽  
Physiological Variables ◽  
Fmri Signal ◽  
Oxygenation Level ◽  
Neurochemical Profile

Processing of incoming sensory stimulation triggers an increase of cerebral perfusion and blood oxygenation (neurovascular response) as well as an alteration of the metabolic neurochemical profile (neurometabolic response). Here we show that perceived and unperceived isoluminant chromatic flickering stimuli designed to have similar neurovascular responses as measured by blood oxygenation level dependent functional MRI (BOLD-fMRI) in primary visual cortex (V1) have markedly different neurometabolic responses as measured by functional MRS. In particular, a significant regional buildup of lactate, an index of aerobic glycolysis, and glutamate, an index of malate-aspartate shuttle, occurred in V1 only when the flickering is perceived, without any relation with behavioral or physiological variables. Wheras the BOLD-fMRI signal in V1, a proxy for input to V1, was insensitive to flickering perception by design, the BOLD-fMRI signal in secondary visual areas was larger during perceived than unperceived flickering indicating increased output from V1. These results indicate that the upregulation of energy metabolism induced by visual stimulation depends on the type of information processing taking place in V1, and that 1H-fMRS provides unique information about local input/output balance that is not measured by BOLD-fMRI.

scholarly journals Physiological and pathological brain activation in the anesthetized rat produces hemodynamic-dependent cortical temperature increases that can confound the BOLD fMRI signal

2017 ◽  
Author(s):  
Samuel S. Harris ◽  
Luke W. Boorman ◽  
Devashish Das ◽  
Aneurin J. Kennerley ◽  
Paul S. Sharp ◽  
...  
Keyword(s):  
Core Temperature ◽  
Hemoglobin Concentration ◽  
Sensory Stimulation ◽  
Blood Oxygenation ◽  
Experimental Methodology ◽  
Temperature Changes ◽  
Bold Fmri ◽  
Fmri Signal ◽  
Acute Seizures ◽  
Cortical Temperature

AbstractAnesthetized rodent models are ubiquitous in pre-clinical neuroimaging studies. However, because the associated cerebral morphology and experimental methodology results in a profound negative brain-core temperature differential, cerebral temperature changes during functional activation are likely to be principally driven by local inflow of fresh, core-temperature, blood. This presents a confound to the interpretation of blood-oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) data acquired from such models, since this signal is also critically temperature-dependent. Nevertheless, previous investigation on the subject is surprisingly sparse. Here, we address this issue through use of a novel multi-modal methodology in the urethane anesthetized rat. We reveal that sensory stimulation, hypercapnia and recurrent acute seizures induce significant increases in cortical temperature that are preferentially correlated to changes in total hemoglobin concentration, relative to cerebral blood flow and oxidative metabolism. Furthermore, using a phantom-based evaluation of the effect of such temperature changes on the BOLD fMRI signal, we demonstrate a robust inverse relationship between the two. These findings indicate that temperature increases, due to functional hyperemia, should be accounted for to ensure accurate interpretation of BOLD fMRI signals in pre-clinical neuroimaging studies.

scholarly journals Altered neurochemical coupling in the occipital cortex in migraine with visual aura

Cephalalgia ◽  
2015 ◽  
Vol 35 (11) ◽  
pp. 1025-1030 ◽  
Author(s):  
Holly Bridge ◽  
Charlotte J Stagg ◽  
Jamie Near ◽  
Chi-ieong Lau ◽  
Aimee Zisner ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Stimulation ◽  
Occipital Cortex ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Resonance Spectroscopy ◽  
Bold Signal ◽  
Visual Aura ◽  
Oxygenation Level ◽  
Neurochemical Profile

Background Visual aura is present in about one-third of migraine patients and triggering by bright or flickering lights is frequently reported. Method Using migraine with visual aura patients, we investigated the neurochemical profile of the visual cortex using magnetic resonance spectroscopy. Specifically, glutamate/creatine and GABA/creatine ratios were quantified in the occipital cortex of female migraine patients. Results GABA levels in the occipital cortex of migraine patients were lower than that of controls. Glutamate levels in migraine patients, but not controls, correlated with the blood-oxygenation-level-dependent (BOLD) signal in the primary visual cortex during visual stimulation. Conclusion Migraine with visual aura appears to disrupt the excitation-inhibition coupling in the occipital cortex.

scholarly journals Large Enhancement of Perfusion Contribution on fMRI Signal

2012 ◽  
Vol 32 (5) ◽  
pp. 907-918 ◽  
Author(s):  
Xiao Wang ◽  
Xiao-Hong Zhu ◽  
Yi Zhang ◽  
Wei Chen
Keyword(s):  
Visual Stimulation ◽  
Human Subjects ◽  
Brain Activity ◽  
Human Study ◽  
Blood Oxygenation ◽  
Calibration Model ◽  
Linear Superposition ◽  
Fmri Signal ◽  
Oxygenation Level ◽  
True Blood

The perfusion contribution to the total functional magnetic resonance imaging (fMRI) signal was investigated using a rat model with mild hypercapnia at 9.4 T, and human subjects with visual stimulation at 4 T. It was found that the total fMRI signal change could be approximated as a linear superposition of ‘true’ blood oxygenation level-dependent (BOLD; T2/T2*) effect and the blood flow-related ( T1) effect. The latter effect was significantly enhanced by using short repetition time and large radiofrequency pulse flip angle and became comparable to the ‘true’ BOLD signal in response to a mild hypercapnia in the rat brain, resulting in an improved contrast-to-noise ratio (CNR). Bipolar diffusion gradients suppressed the intravascular signals but had no significant effect on the flow-related signal. Similar results of enhanced fMRI signal were observed in the human study. The overall results suggest that the observed flow-related signal enhancement is likely originated from perfusion, and this enhancement can improve CNR and the spatial specificity for mapping brain activity and physiology changes. The nature of mixed BOLD and perfusion-related contributions in the total fMRI signal also has implication on BOLD quantification, in particular, the BOLD calibration model commonly used to estimate the change of cerebral metabolic rate of oxygen.

scholarly journals Physiological origin for the BOLD poststimulus undershoot in human brain: Vascular compliance versus oxygen metabolism

2011 ◽  
Vol 31 (7) ◽  
pp. 1599-1611 ◽  
Author(s):  
Jun Hua ◽  
Robert D Stevens ◽  
Alan J Huang ◽  
James J Pekar ◽  
Peter CM van Zijl
Keyword(s):  
Cerebral Blood Volume ◽  
Visual Stimulation ◽  
Oxygen Metabolism ◽  
Blood Oxygenation ◽  
Biophysical Model ◽  
Breath Hold ◽  
Signal Recovery ◽  
Vascular Compliance ◽  
Oxygenation Level ◽  
Bold Undershoot

The poststimulus blood oxygenation level-dependent (BOLD) undershoot has been attributed to two main plausible origins: delayed vascular compliance based on delayed cerebral blood volume (CBV) recovery and a sustained increased oxygen metabolism after stimulus cessation. To investigate these contributions, multimodal functional magnetic resonance imaging was employed to monitor responses of BOLD, cerebral blood flow (CBF), total CBV, and arterial CBV (CBVa) in human visual cortex after brief breath hold and visual stimulation. In visual experiments, after stimulus cessation, CBVa was restored to baseline in 7.9 ± 3.4 seconds, and CBF and CBV in 14.8 ± 5.0 seconds and 16.1 ± 5.8 seconds, respectively, all significantly faster than BOLD signal recovery after undershoot (28.1 ± 5.5 seconds). During the BOLD undershoot, postarterial CBV (CBVpa, capillaries and venules) was slightly elevated (2.4 ± 1.8%), and cerebral metabolic rate of oxygen ( CMRO2) was above baseline (10.6 ± 7.4%). Following breath hold, however, CBF, CBV, CBVa and BOLD signals all returned to baseline in ∼20 seconds. No significant BOLD undershoot, and residual CBVpa dilation were observed, and CMRO2 did not substantially differ from baseline. These data suggest that both delayed CBVpa recovery and enduring increased oxidative metabolism impact the BOLD undershoot. Using a biophysical model, their relative contributions were estimated to be 19.7 ± 15.9% and 78.7 ± 18.6%, respectively.

scholarly journals A Functional Magnetic Resonance Imaging Technique Based on Nulling Extravascular Gray Matter Signal

2008 ◽  
Vol 29 (1) ◽  
pp. 144-156 ◽  
Author(s):  
Yuji Shen ◽  
Risto A Kauppinen ◽  
Rishma Vidyasagar ◽  
Xavier Golay
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Gray Matter ◽  
Visual Stimulation ◽  
Brain Activation ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Fmri Signal

A new functional magnetic resonance imaging (fMRI) technique is proposed based on nulling the extravascular gray matter (GM) signal, using a spatially nonselective inversion pulse. The remaining MR signal provides cerebral blood volume (CBV) information from brain activation. A theoretical framework is provided to characterize the sources of GM-nulled (GMN) fMRI signal, effects of partial voluming of cerebrospinal fluid (CSF) and white matter, and behaviors of GMN fMRI signal during brain activation. Visual stimulation paradigm was used to explore the GMN fMRI signal behavior in the human brain at 3T. It is shown that the GMN fMRI signal increases by 7.2% ± 1.5%, which is two to three times more than that obtained with vascular space occupancy (VASO)-dependent fMRI (−3.2% ± 0.2%) or blood oxygenation level-dependent (BOLD) fMRI (2.9% ± 0.7%), using a TR of 3,000 ms and a resolution of 2 × 2 × 5 mm3. Under these conditions the fMRI signal-to-noise ratio (SNRfMRI) for BOLD, GMN, and VASO images was 4.97 ± 0.76, 4.56 ± 0.86, and 2.43 ± 1.06, respectively. Our study shows that both signal intensity and activation volume in GMN fMRI depend on spatial resolution because of partial voluming from CSF. It is shown that GMN fMRI is a convenient tool to assess CBV changes associated with brain activation.

scholarly journals Relationship of the BOLD Signal with VEP for Ultrashort Duration Visual Stimuli (0.1 to 5 ms) in Humans

2009 ◽  
Vol 30 (2) ◽  
pp. 449-458 ◽  
Author(s):  
Barış Yeşilyurt ◽  
Kevin Whittingstall ◽  
Kâmil Uğurbil ◽  
Nikos K Logothetis ◽  
Kâmil Uludağ
Keyword(s):  
Brain Function ◽  
Temporal Dynamics ◽  
Visual Stimulation ◽  
Impulse Response Function ◽  
Blood Oxygenation ◽  
Context Dependency ◽  
Oxygenation Level ◽  
Relationship Of ◽  
The Relationship ◽  
The Brain

There is currently a great interest to combine electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to study brain function. Earlier studies have shown different EEG components to correlate well with the fMRI signal arguing for a complex relationship between both measurements. In this study, using separate EEG and fMRI measurements, we show that (1) 0.1 ms visual stimulation evokes detectable hemodynamic and visual-evoked potential (VEP) responses, (2) the negative VEP deflection at ∼80 ms (N2) co-varies with stimulus duration/intensity such as with blood oxygenation level-dependent (BOLD) response; the positive deflection at ∼120 ms (P2) does not, and (3) although the N2 VEP–BOLD relationship is approximately linear, deviation is evident at the limit of zero N2 VEP. The latter finding argues that, although EEG and fMRI measurements can co-vary, they reflect partially independent processes in the brain tissue. Finally, it is shown that the stimulus-induced impulse response function (IRF) at 0.1 ms and the intrinsic IRF during rest have different temporal dynamics, possibly due to predominance of neuromodulation during rest as compared with neurotransmission during stimulation. These results extend earlier findings regarding VEP–BOLD coupling and highlight the component- and context-dependency of the relationship between evoked potentials and hemodynamic responses.

Sex Differences in Blood-Oxygenation-Level-Dependent Functional MRI With Primary Visual Stimulation

1998 ◽  
Vol 155 (3) ◽  
pp. 434-436 ◽  
Author(s):  
Jonathan M. Levin ◽  
Marjorie H. Ross ◽  
Jack H. Mendelson ◽  
Nancy K. Mello ◽  
Bruce M. Cohen ◽  
...  
Keyword(s):  
Sex Differences ◽  
Functional Mri ◽  
Visual Stimulation ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

Effect of Luminance Contrast on BOLD fMRI Response in Human Primary Visual Areas

1998 ◽  
Vol 79 (4) ◽  
pp. 2204-2207 ◽  
Author(s):  
Bradley G. Goodyear ◽  
Ravi S. Menon
Keyword(s):  
Luminance Contrast ◽  
Blood Oxygenation ◽  
Planar Imaging ◽  
Bold Fmri ◽  
Activation Level ◽  
Red Led ◽  
Visual Areas ◽  
Oxygenation Level ◽  
Fmri Response ◽  
Image Pixels

Goodyear, Bradley G. and Ravi S. Menon. Effect of luminance contrast on BOLD fMRI response in human primary visual areas. J. Neurophysiol. 79: 2204–2207, 1998. In this study, we examined the effect of stimulus luminance contrast on blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging within human visual cortex (V1 and extrastriate). Between experiments, the calibrated luminance of a single red LED covering 2° of the subject's visual field was changed relative to a constant background luminance. This stimulus provided a different foveal luminance contrast for each experiment. We used an echo planar imaging sequence to collect blood-oxygenation-sensitive images during and in the absence of the presented stimulus. Our results showed that within V1 there was an increase in the spatial extent of activation with increasing stimulus contrast, but no trend was seen within extrastriate. In both V1 and extrastriate, the local mean activation level for all activated image pixels remained constant with increasing luminance contrast. However, when we investigated activated pixels common to all luminance contrast levels, we found that there was an increase in the mean activation level within V1, but not within extrastriate. These results suggest that there is an increase in the activity of cells in V1 with increasing luminance contrast.

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