ANTINOCICEPTIVE EFFECT OF MORPHINE IN α-CHLORALOSE AND ISOFLURANE ANESTHETIZED RATS USING BOLD fMRI

2008 ◽  
Vol 20 (01) ◽  
pp. 39-46
Author(s):  
Chin-Mei Chen ◽  
Yen-Yu I. Shih ◽  
Tiing-Yee Siow ◽  
Yun-Chen Chiang ◽  
Chen Chang ◽  
...  
Keyword(s):  
Imaging Technique ◽  
Antinociceptive Effect ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Brain Areas ◽  
Oxygenation Level ◽  
Pain Testing ◽  
The Brain ◽  
Significant Activation

Blood oxygenation level dependent functional magnetic resonance imaging technique was used to explore the antinociceptive effect of morphine in the rat brain under α-chloralose and isoflurane anesthesia. Formalin was used as a pain-testing model which could produce significant activation in various brain areas. The results also showed that morphine pretreatment modulate neurovascular activities evoked by formalin stimulation, especially in cingulate cortex, somatosensory cortex, caudate putamen, visual cortex, and hippocampus. The present study identified the brain areas involved in modulating nociception.

scholarly journals A studyforrest extension, MEG recordings while watching the audio-visual movie "Forrest Gump"

2021 ◽  
Author(s):  
Xingyu Liu ◽  
Yuxuan Dai ◽  
Hailun Xie ◽  
Zonglei Zhen
Keyword(s):  
Neuronal Activity ◽  
Brain Function ◽  
Ecological Validity ◽  
Blood Oxygenation ◽  
Free Access ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Oxygenation Level ◽  
The Brain ◽  
The Magnetic Field

Naturalistic stimuli, such as movies, are being increasingly used to map brain function because of their high ecological validity. The pioneering studyforrest and other naturalistic neuroimaging projects have provided free access to multiple movie-watching functional magnetic resonance imaging (fMRI) datasets to prompt the community for naturalistic experimental paradigms. However, sluggish blood-oxygenation-level-dependent fMRI signals are incapable of resolving neuronal activity with the temporal resolution at which it unfolds. Instead, magnetoencephalography (MEG) measures changes in the magnetic field produced by neuronal activity and is able to capture rich dynamics of the brain at the millisecond level while watching naturalistic movies. Herein, we present the first public prolonged MEG dataset collected from 11 participants while watching the 2 h long audio-visual movie "Forrest Gump". Minimally preprocessed data was also provided to facilitate the use. As a studyforrest extension, we envision that this dataset, together with fMRI data from the studyforrest project, will serve as a foundation for exploring the neural dynamics of various cognitive functions in real-world contexts.

Attenuated Brain Response to Auditory Word Stimulation with Sevoflurane

2005 ◽  
Vol 103 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Chantal Kerssens ◽  
Stephan Hamann ◽  
Scott Peltier ◽  
Xiaoping P. Hu ◽  
Michael G. Byas-Smith ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Occipital Cortex ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Brain Response ◽  
Auditory Word ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

Background Functional magnetic resonance imaging offers a compelling, new perspective on altered brain function but is sparsely used in studies of anesthetic effect. To examine effects on verbal memory encoding, the authors imaged human brain response to auditory word stimulation using functional magnetic resonance imaging at different concentrations of an agent not previously studied, and tested memory after recovery. Methods Six male volunteers were studied breathing 0.0, 2.0, and 1.0% end-tidal sevoflurane (awake, deep, and light states, respectively) via laryngeal mask. In each condition, they heard 15 two-syllable English nouns via closed headphones. Each word was repeated 15 times (1/s), followed by 15 s of rest. Blood oxygenation level-dependent brain activations during blocks of stimulation versus rest were assessed with a 3-T Siemens Trio scanner and a 20-voxel spatial extent threshold. Memory was tested approximately 1.5 h after recovery with an auditory recognition task (chance performance = 33% correct). Results Scans showed widespread activations (P < 0.005, uncorrected) in the awake state, including bilateral superior temporal, frontal, and parietal cortex, right occipital cortex, bilateral thalamus, striatum, hippocampus, and cerebellum; more limited activations in the light state (bilateral superior temporal gyrus, right thalamus, bilateral parietal cortex, left frontal cortex, and right occipital cortex); and no significant auditory-related activation in the deep state. During recognition testing, subjects correctly selected 77 +/- 12% of words presented while they were awake as "old," versus 32 +/- 15 and 42 +/- 8% (P < 0.01) correct for the light and deep stages, respectively. Conclusions Sevoflurane induces dose-dependent suppression of auditory blood oxygenation level-dependent signals, which likely limits the ability of words to be processed during anesthesia and compromises memory.

scholarly journals Greater BOLD Variability is Associated With Poorer Cognitive Function in an Adult Lifespan Sample

2020 ◽  
Vol 31 (1) ◽  
pp. 562-574
Author(s):  
Maria A Boylan ◽  
Chris M Foster ◽  
Ekarin E Pongpipat ◽  
Christina E Webb ◽  
Karen M Rodrigue ◽  
...  
Keyword(s):  
Healthy Aging ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Adult Lifespan ◽  
Age Related ◽  
Oxygenation Level ◽  
Linear Slope ◽  
Subcortical Regions ◽  
Effects Of Aging

Abstract Moment-to-moment fluctuations in brain signal assessed by functional magnetic resonance imaging blood oxygenation level dependent (BOLD) variability is increasingly thought to represent important “signal” rather than measurement-related “noise.” Efforts to characterize BOLD variability in healthy aging have yielded mixed outcomes, demonstrating both age-related increases and decreases in BOLD variability and both detrimental and beneficial associations. Utilizing BOLD mean-squared-successive-differences (MSSD) during a digit n-back working memory (WM) task in a sample of healthy adults (aged 20–94 years; n = 171), we examined effects of aging on whole-brain 1) BOLD variability during task (mean condition MSSD across 0–2–3-4 back conditions), 2) BOLD variability modulation to incrementally increasing WM difficulty (linear slope from 0–2–3-4 back), and 3) the association of age-related differences in variability with in- and out-of-scanner WM performance. Widespread cortical and subcortical regions evidenced increased mean variability with increasing age, with no regions evidencing age-related decrease in variability. Additionally, posterior cingulate/precuneus exhibited increased variability to WM difficulty. Notably, both age-related increases in BOLD variability were associated with significantly poorer WM performance in all but the oldest adults. These findings lend support to the growing corpus suggesting that brain-signal variability is altered in healthy aging; specifically, in this adult lifespan sample, BOLD-variability increased with age and was detrimental to cognitive performance.

scholarly journals Measuring vascular reactivity with resting-state blood oxygenation level-dependent (BOLD) signal fluctuations: A potential alternative to the breath-holding challenge?

2016 ◽  
Vol 37 (7) ◽  
pp. 2526-2538 ◽  
Author(s):  
Hesamoddin Jahanian ◽  
Thomas Christen ◽  
Michael E Moseley ◽  
Nicholas M Pajewski ◽  
Clinton B Wright ◽  
...  
Keyword(s):  
Functional Magnetic Resonance Imaging ◽  
Resting State ◽  
Vascular Reactivity ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Breath Holding ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide (PaCO2) levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients. In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal. We studied a cohort of 28 older adults (69 ± 7 years) and found that six of them (21%) could not perform the breath-holding protocol, based on an objective comparison with an idealized respiratory waveform. In the subjects that could comply, we found a strong linear correlation between data extracted from spontaneous resting-state functional magnetic resonance imaging signal fluctuations and the blood oxygenation level-dependent percentage signal change during breath-holding challenge ( R2 = 0.57 and 0.61 for resting-state physiological fluctuation regression and resting-state coefficient of variation methods, respectively). This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical.

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