Calibration of BOLD fMRI using breath holding reduces group variance during a cognitive task

Thomason, Moriah E.; Foland, Lara C.; Glover, Gary H.

doi:10.1002/hbm.20241

Cited by 113 publications

(160 citation statements)

References 23 publications

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“…As has been reported previously (Thomason et al, 2007;Handwerker et al, 2007), the BH response was significantly and positively correlated with the response to the visual activation task, accounting for 23% of the variance. The portion of the response to the visual activation task that was not related to cerebrovascular reactivity was not statistically significantly related to either smoking status or diagnosis.…”

Section: Discussion Of the Relationship Between The Visual Activationsupporting

confidence: 83%

“…Since there were 2 runs of the visual activation task and thus 2 masks, the masks were concatenated (summed) to produce a single visual cortex ROI for purposes of masking the BH percent signal change data. Following Thomason et al (2007) only BH responses that were greater than some threshold (in our case 0.25% signal change) were included in the estimate of median percent signal change in BH in the visual cortex ROI.…”

Section: Specific Methods For the Relating The Results Of The Visual mentioning

confidence: 99%

“…The BOLD response to the BH task is thought to reflect cerebrovascular reactivity (Thomason et al, 2007). During this task subjects hold their breath after inspiration for 16 seconds and then breathe normally for 16 seconds.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to cognitive and sensory BOLD activations, the BH-induced signal increase is understood to occur in the absence of an increase in neuronal metabolism and the rate of dHb production remains at a basal level. Thus, the increase in the BOLD signal from trough-to-peak during the BH paradigm is thought to provide a measure of non-cognitive, maximal BOLD response (cerebrovascular reactivity) (Thomason et al, 2007). The inclusion of both the VA and the BH task should facilitate the assessment of potential neural and cerebrovascular effects of a chronic smoking history.…”

Section: Introductionmentioning

confidence: 99%

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Chronic smoking and the BOLD response to a visual activation task and a breath hold task in patients with schizophrenia and healthy controls

et al. 2008

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Many psychiatric patient groups smoke heavily, but little is known regarding the effects of this habit on functional brain imaging results. The present report assesses the effect of chronic smoking on the blood-oxygen-level-dependent (BOLD) response to a simple visual activation (VA) task and a breath hold (BH) task in patients with schizophrenia. Eight healthy controls and twelve patients with schizophrenia were studied. Half of each group had never smoked and the other half of each group had smoked for more than 10 pack years. Responses to the VA task were assessed in the visual cortex and responses to the BH task were assessed in gray matter generally. There were four fMRI dependent measures: (1) median percent signal change; (2) activation volume (in voxels); (3) time-to-peak of the impulse response function (IRF); and (4) time-to-trough of the IRF. All measures were tested as dependent variables in an ANCOVA with diagnosis and smoking status as crossed factors and age as a covariate. Heavy smokers had 22% larger percent signal change for the VA task and 50% larger percent signal change for the BH task. Patients had a 40% larger percent signal change for the breathhold task. Other statistically significant effects of smoking history on activation volume and the timing of the brain responses were noted. If replicated, the results may have important implications for fMRI studies comparing groups with markedly different smoking habits, such as studies comparing patients with schizophrenia, 60-90% of whom smoke, and healthy controls, who smoke with a much lower frequency.

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Section: Discussion Of the Relationship Between The Visual Activationsupporting

confidence: 83%

Section: Specific Methods For the Relating The Results Of The Visual mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chronic smoking and the BOLD response to a visual activation task and a breath hold task in patients with schizophrenia and healthy controls

et al. 2008

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“…Spatial calibration methods have been proposed involving hypercapnia (Bandettini and Wong 1997;Cohen et al 2004;Thomason et al 2007). CO 2 stress (Chiarelli et al 2007;Handwerker et al 2007), and, recently, even the resting state fluctuation data (Birn et al 2008).…”

Section: Spatial Resolutionmentioning

confidence: 99%

Functional MRI Limitations and Aspirations

Bandettini

2009

Neural Correlates of Thinking

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PrefaceThe idea of the present book emerged on the island of Elba in the summer of 2006 during an enjoyable and very fruitful workshop on thinking with the participation of most of the contributors of the present volume.The main intention behind the book is to address thinking by surveying the contribution of various functional neuroimaging methods to our understanding of the neural underpinnings of thinking. The major focus is on the methods applicable to the neurobiological study of human thinking, since much of what we consider complex thinking has to be considered as a part of the distinctive features of human nature.Despite the fact that we are far from a full understanding of the modularity of the human brain, the use of functional imaging techniques is obviously based on the premise that brain functions are modular.We are grateful to the distinguished authors, coming from different backgrounds, for their commitment to this project, which represents a true interdisciplinary approach, as is mandatory for this fascinating and challenging topic. We are also proud to have been able to recruit an outstanding worldwide team of contributors.We also wish to thank Anette Lindqvist and Dieter Czechlik from Springer Science+Business Media for their enthusiasm and constant support. Without their optimism and tireless efforts this volume would not have been possible. Munich, GermanyEduard Abstract Most would agree that knowing precisely what was happening in the brain during the act of thinking would help in our pursuit to understand what thinking really is. This chapter describes the basics, limits, and future directions of one of the more effective tools we have to observe the human brain while it is functioningfunctional MRI. Functional MRI emerged in the early 1990s, and has since grown explosively in utility. In this chapter, an in-depth exploration is carried out of what limits functional MRI to a spatial resolution of millimeters and a temporal resolution of seconds. In addition, issues of how sensitive functional MRI is in detecting brain activity and how deeply we can interpret the signal changes are explored. Lastly, the chapter ends with a discussion on how imaging might be essential, or perhaps irrelevant, to understanding thinking.

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Improving fMRI sensitivity by normalization of basal physiologic state

Lu¹,

Yezhuvath²,

Xiao³

2009

Human Brain Mapping

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The power of fMRI in assessing neural activities is hampered by inter-subject variations in basal physiologic parameters, which may not be related to neural activation but has a modulatory effect on fMRI signals. Therefore, normalization of fMRI signals with these parameters is useful in reducing variations and improving sensitivity of this important technique. Recently, we have shown that basal venous oxygenation is a significant modulator of fMRI signals and individuals with higher venous oxygenation tend to have lower fMRI signals. In this study, we aim to test the utility of venous oxygenation normalization in distinguishing subject groups. A “model” condition was used in which two visual stimuli with different flashing frequencies were used to stimulate two subject groups, respectively, thereby simulating the situation of control and patient groups. It was found that visual-evoked BOLD signal is significantly correlated with baseline venous T2 (p=0.0003) and inclusion of physiologic modulator in the regression analysis can substantially reduce p values of group-level statistical tests. When applied to voxel-wise analysis, the normalization process can allow the detection of more significant voxels. The utility of other basal parameters, including blood pressure, heart rate, arterial oxygenation and end-tidal CO2, in BOLD normalization was also assessed and it was found that the improvement was less significant. Time-to-peak of the BOLD responses was also studied and it was found that subjects with higher basal venous oxygenation tend to have slower BOLD responses.

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Calibration of BOLD fMRI using breath holding reduces group variance during a cognitive task

Cited by 113 publications

References 23 publications

Chronic smoking and the BOLD response to a visual activation task and a breath hold task in patients with schizophrenia and healthy controls

Chronic smoking and the BOLD response to a visual activation task and a breath hold task in patients with schizophrenia and healthy controls

Functional MRI Limitations and Aspirations

Improving fMRI sensitivity by normalization of basal physiologic state

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