Vascular dynamics and BOLD fMRI: CBF level effects and analysis considerations

Vazquez, Alberto L.; Cohen, Eric R.; Gulani, Vikas; Hernandez‐García, Luis; Zheng, Ying; Lee, Gregory R.; Kim, Seong Gi; Grotberg, James B.; Noll, Douglas C.

doi:10.1016/j.neuroimage.2006.04.195

Cited by 54 publications

(44 citation statements)

References 35 publications

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“…The relatively small number of subjects assessed in this initial study calls for caution in the interpretation of the present between-group null effect, since such an effect could be due to insufficient statistical power, though we note that the comparison studies referenced above (some showing positive between-group effects) comprised subject samples of similar size. Alternatively, the lack of group differences reported here could be an artifact of elevated baseline amygdala blood flow in GAD consistent with findings that baseline blood flow correlates negatively with the magnitude of evoked blood oxygenation level-dependent (BOLD) responses (46). This possibility could be explicitly tested using positron-emission tomography (PET) imaging or perfusion imaging in future fMRI studies.…”

Section: Discussionsupporting

confidence: 67%

A Functional Magnetic Resonance Imaging Predictor of Treatment Response to Venlafaxine in Generalized Anxiety Disorder

Whalen

Johnstone

Somerville

et al. 2008

Biological Psychiatry

186

147

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Background-Functional magnetic resonance imaging (fMRI) holds promise as a noninvasive means of identifying neural responses that can be used to predict treatment response before beginning a drug trial. Imaging paradigms employing facial expressions as presented stimuli have been shown to activate the amygdala and anterior cingulate cortex (ACC). Here, we sought to determine whether pretreatment amygdala and rostral ACC (rACC) reactivity to facial expressions could predict treatment outcomes in patients with generalized anxiety disorder (GAD).

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Section: Discussionsupporting

confidence: 67%

A Functional Magnetic Resonance Imaging Predictor of Treatment Response to Venlafaxine in Generalized Anxiety Disorder

Whalen

Johnstone

Somerville

et al. 2008

Biological Psychiatry

186

147

View full text Add to dashboard Cite

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“…The BOLD signal reflects changes in CBF relative to changes in cerebral metabolic rate of oxygen (CMRO 2 ) (Buxton et al, 2004). By implementing a vascular model of the hemodynamic response, Vazquez et al (2006) have suggested that changes in baseline CBF might influence latency and amplitude parameters of the BOLD signal. Concerning development, global cortical CBF was shown to increase during early childhood, peaking at about age 5 to 6, and then to decline, reaching an adult level in late adolescence (Chiron et al, 1992;Takahashi et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Temporal dynamics of perisylvian activation during language processing in children and adults

2008

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The perisylvian region of the human cortex is known to play a major role in language processing. Especially the superior temporal cortex (STC) and the inferior frontal cortex (IFC) have been investigated with respect to their particular involvement in language comprehension. In the present research, the timing of recruitment of these language-related brain areas in both hemispheres was examined as a function of age using functional imaging data of 6-year-old children and adults with a special focus on blood oxygenation level dependent (BOLD) response time courses. The results show that children's activation time courses differ from that of adults. First, children show an overall later peak of BOLD responses. Second, children's IFC responds much later than their STC, while in adults the difference between both regions is less pronounced. Within the STC, both groups show similar regionally U-shaped activation patterns with fastest peaks in voxels at the STC's mid-portion around Heschl's gyrus and longer latencies in anterior and posterior directions, suggesting a coarsely similar information flow in adults and children in the temporal region. Finally, children in contrast to adults, display a temporal primacy of right over left hemispheric activation. The observed overall latency differences between children and adults are in line with the assumption of ongoing maturation in perisylvian brain regions and the connections between them. A functional perspective on BOLD timing argues for a developmental change from higher processing costs in children compared to adults due to slower and less automatic language processes, in particular those located in the IFC. The observed hemispheric differences are discussed in the context of developmental models assuming a high reliance on right-hemisphere-based suprasegmental information processing during language comprehension in childhood.

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“…Thus, stimulation of the central region could have had a reduced impact to the BOLD signal, thus producing apparent suppression (see Methods). Increased baseline rCBF is also known to reduce stimulus-induced BOLD activation [Stefanovic et al, 2006;Vazquez et al, 2006]. We probed the possible contribution of these nonlinearities by varying the stimulus contrast.…”

Section: Figurementioning

confidence: 99%

Quantitative multifocal fMRI shows active suppression in human V1

Pihlaja¹,

Henriksson²,

James³

et al. 2008

Human Brain Mapping

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Multifocal functional magnetic resonance imaging has recently been introduced as an alternative method for retinotopic mapping, and it enables effective functional localization of multiple regions-of-interest in the visual cortex. In this study we characterized interactions in V1 with spatially and temporally identical stimuli presented alone, or as a part of a nine-region multifocal stimulus. We compared stimuli at different contrasts, collinear and orthogonal orientations and spatial frequencies one octave apart. Results show clear attenuation of BOLD signal from the central region in the multifocal condition. The observed modulation in BOLD signal could be produced either by neural suppression resulting from stimulation of adjacent regions of visual field, or alternatively by hemodynamic saturation or stealing effects in V1. However, we find that attenuation of the central response persists through a range of contrasts, and that its strength varies with relative orientation and spatial frequency of the central and surrounding stimulus regions, indicating active suppression mechanisms of neural origin. Our results also demonstrate that the extent of the signal spreading is commensurate with the extent of the horizontal connections in primate V1.

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Vascular dynamics and BOLD fMRI: CBF level effects and analysis considerations

Cited by 54 publications

References 35 publications

A Functional Magnetic Resonance Imaging Predictor of Treatment Response to Venlafaxine in Generalized Anxiety Disorder

A Functional Magnetic Resonance Imaging Predictor of Treatment Response to Venlafaxine in Generalized Anxiety Disorder

Temporal dynamics of perisylvian activation during language processing in children and adults

Quantitative multifocal fMRI shows active suppression in human V1

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