scholarly journals Evolution of the Dynamic Changes in Functional Cerebral Oxidative Metabolism from Tissue Mitochondria to Blood Oxygen

2012 ◽  
Vol 32 (4) ◽  
pp. 745-758 ◽  
Author(s):  
Alberto L Vazquez ◽  
Mitsuhiro Fukuda ◽  
Seong-Gi Kim
Keyword(s):  
Metabolic Rate ◽  
Dynamic Properties ◽  
Brain Activity ◽  
Oxygen Electrode ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygen ◽  
Autofluorescence Imaging ◽  
Response Condition ◽  
Intrinsic Signal

The dynamic properties of the cerebral metabolic rate of oxygen consumption (CMRO2) during changes in brain activity remain unclear. Therefore, the spatial and temporal evolution of functional increases in CMRO2 was investigated in the rat somato-sensory cortex during forelimb stimulation under a suppressed blood flow response condition. Temporally, stimulation elicited a fast increase in tissue mitochondria CMRO2 described by a time constant of ~ 1 second measured using flavoprotein autofluorescence imaging. CMRO2-driven changes in the tissue oxygen tension measured using an oxygen electrode and blood oxygenation measured using optical imaging of intrinsic signal followed; however, these changes were slow with time constants of ~ 5 and ~ 10 seconds, respectively. This slow change in CMRO2-driven blood oxygenation partly explains the commonly observed post-stimulus blood oxygen level-dependent (BOLD) undershoot. Spatially, the changes in mitochondria CMRO2 were similar to the changes in blood oxygenation. Finally, the increases in CMRO2 were well correlated with the evoked multi-unit spiking activity. These findings show that dynamic CMRO2 calculations made using only blood oxygenation data (e.g., BOLD functional magnetic resonance imaging (fMRI)) do not directly reflect the temporal changes in the tissue's mitochondria metabolic rate; however, the findings presented can bridge the gap between the changes in cellular oxidative rate and blood oxygenation.

Differential neural correlates of reciprocal activation and cocontraction control in dorsal and ventral premotor cortices

2012 ◽  
Vol 107 (1) ◽  
pp. 126-133 ◽  
Author(s):  
Masahiko Haruno ◽  
Gowrishankar Ganesh ◽  
Etienne Burdet ◽  
Mitsuo Kawato
Keyword(s):  
Brain Activity ◽  
Premotor Cortex ◽  
Neural Correlates ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Dorsal Premotor Cortex ◽  
Blood Oxygen Level ◽  
Efficient Control ◽  
Dependent Activity ◽  
The Brain

Efficient control of reciprocal activation and cocontraction of the muscles are critical to perform skillful actions with suitable force and impedance. However, it remains unclear how the brain controls force and impedance while recruiting the same set of muscles as actuators. Does control take place at the single muscle level leading to force and impedance, or are there higher-order centers dedicated to controlling force and impedance? We addressed this question using functional MRI during voluntary isometric wrist contractions with online electromyogram feedback. Comparison of the brain activity between the conditions requiring control of either wrist torque or cocontraction demonstrates that blood oxygen level-dependent activity in the caudo-dorsal premotor cortex (PMd) correlates well with torque, whereas the activity in the ventral premotor cortex (PMv) correlates well with the level of cocontraction. This suggests distinct roles of the PMd and PMv in the voluntary control of reciprocal activation and cocontraction of muscles, respectively.

Effects of carbogen inhalation on tumor oxygenation: Comparison of magnetic resonance and oxygen electrode measurements

1996 ◽  
Vol 54 ◽  
pp. 882-883
Author(s):  
G.S. Karczmar ◽  
J.N. River ◽  
H.A. Al-Hallaq ◽  
M.Z. Lewis ◽  
H. Oikawa ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Cancer Patients ◽  
Tumor Response ◽  
Tissue Concentration ◽  
Oxygen Electrode ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygenation ◽  
Response To Therapy ◽  
Tumor Oxygenation ◽  
Blood Oxygen Level

Introduction:Radiotherapy is most effective in tumors in which the tissue concentration of oxygen is high. The potential of tumor oxygenating treatments (i.e., treatments which increase tumor oxygenation as an adjunct to radiotherapy; ‘TOX’s’) to substantially improve tumor response to therapy has been clearly demonstrated in animal models and in some studies of cancer patients. However, despite some initial successes, the ability of TOX‘s to help a large percentage of cancer patients has been disappointing. The reasons for this are not clear because there is currently no method which is routinely used to image the effects of TOX‘s on tumor oxygenation with high resolution and accuracy. Development of improved TOX‘s and optimization of their clinical application would be significantly advanced by such measurements.Previous work in this laboratory and other laboratories has demonstrated that Magnetic Resonance (MR) can be used to detect effects of TOX's on tumor blood oxygenation, based on the BOLD effect (blood oxygen level dependent contrast).

scholarly journals Human non-REM sleep and the mean global BOLD signal

2018 ◽  
Vol 39 (11) ◽  
pp. 2210-2222 ◽  
Author(s):  
Mark P McAvoy ◽  
Enzo Tagliazucchi ◽  
Helmut Laufs ◽  
Marcus E Raichle
Keyword(s):  
Blood Flow ◽  
Rem Sleep ◽  
Brain Activity ◽  
Oxygen Metabolism ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Bold Signal ◽  
Blood Oxygen Level ◽  
The Mean ◽  
Uniform Manner

A hallmark of non-rapid eye movement (REM) sleep is the decreased brain activity as measured by global reductions in cerebral blood flow, oxygen metabolism, and glucose metabolism. It is unknown whether the blood oxygen level dependent (BOLD) signal undergoes similar changes. Here we show that, in contrast to the decreases in blood flow and metabolism, the mean global BOLD signal increases with sleep depth in a regionally non-uniform manner throughout gray matter. We relate our findings to the circulatory and metabolic processes influencing the BOLD signal and conclude that because oxygen consumption decreases proportionately more than blood flow in sleep, the resulting decrease in paramagnetic deoxyhemoglobin accounts for the increase in mean global BOLD signal.

scholarly journals Brain reactivity using fMRI to insomnia stimuli in insomnia patients with discrepancy between subjective and objective sleep

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Young-Bo Kim ◽  
Nambeom Kim ◽  
Jae Jun Lee ◽  
Seo-Eun Cho ◽  
Kyoung-Sae Na ◽  
...  
Keyword(s):  
Brain Activity ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Cognitive Distortion ◽  
Sleep Diary ◽  
Bold Signal ◽  
Blood Oxygen Level ◽  
General Anxiety ◽  
Sleep Deficit ◽  
Perception Of Sleep

AbstractSubjective–objective discrepancy of sleep (SODS) might be related to the distorted perception of sleep deficit and hypersensitivity to insomnia-related stimuli. We investigated differences in brain activation to insomnia-related stimuli among insomnia patients with SODS (SODS group), insomnia patients without SODS (NOSODS group), and healthy controls (HC). Participants were evaluated for subjective and objective sleep using sleep diary and polysomnography. Functional magnetic resonance imaging was conducted during the presentation of insomnia-related (Ins), general anxiety-inducing (Gen), and neutral (Neu) stimuli. Brain reactivity to the contrast of Ins vs. Neu and Gen vs. Neu was compared among the SODS (n = 13), NOSODS (n = 15), and HC (n = 16) groups. In the SODS group compared to other groups, brain areas including the left fusiform, bilateral precuneus, right superior frontal gyrus, genu of corpus callosum, and bilateral anterior corona radiata showed significantly increased blood oxygen level dependent (BOLD) signal in the contrast of Ins vs. Neu. There was no brain region with significantly increased BOLD signal in the Gen vs. Neu contrast in the group comparisons. Increased brain activity to insomnia-related stimuli in several brain regions of the SODS group is likely due to these individuals being more sensitive to sleep-related threat and negative cognitive distortion toward insomnia.

Blood oxygen-level dependent functional assessment of cerebrovascular reactivity: Feasibility for intraoperative 3 Tesla MRI

2016 ◽  
Vol 77 (2) ◽  
pp. 806-813 ◽  
Author(s):  
Jorn Fierstra ◽  
Jan-Karl Burkhardt ◽  
Christiaan Hendrik Bas van Niftrik ◽  
Marco Piccirelli ◽  
Athina Pangalu ◽  
...  
Keyword(s):  
Functional Assessment ◽  
Blood Oxygen Level Dependent ◽  
Cerebrovascular Reactivity ◽  
3 Tesla ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
3 Tesla Mri
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