BOLD-Perfusion Coupling during Monocular and Binocular Stimulation

Previous studies have suggested that during selective activation of a subset of the zones comprising a columnar system in visual cortex, perfusion increases uniformly in all columns of the system, while increases in oxidative metabolism occur predominantly in the activated columns. This could lead to disproportionately large blood oxygenation level-dependent (BOLD) signal increases for a given flow increase during monocular (relative to binocular) stimulation, due to contributions from columns which undergo large increases in perfusion with little or no change in oxidative metabolism. In the present study, we sought to test this hypothesis by measuring BOLD-perfusion coupling ratios in spatially averaged signals over V1 during monocular and binocular visual stimulation. It was found that, although withholding input to one eye resulted in statistically significant decreases in BOLD and perfusion signals in primary visual cortex, the ratio between BOLD and perfusion increases did not change significantly. These results do not support a gross mismatch between spatial patterns of flow and metabolism response during monocular stimulation.

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Origin of Negative Blood Oxygenation Level—Dependent fMRI Signals

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200208000-00002 ◽

2002 ◽

Vol 22 (8) ◽

pp. 908-917 ◽

Cited By ~ 231

Author(s):

Noam Harel ◽

Sang-Pil Lee ◽

Tsukasa Nagaoka ◽

Dae-Shik Kim ◽

Seong-Gi Kim

Keyword(s):

Neural Activity ◽

Spike Activity ◽

Visual Stimulation ◽

Blood Oxygenation Level Dependent ◽

Blood Oxygenation ◽

Bold Signal ◽

Area 18 ◽

Blood Oxygenation Level ◽

Oxygenation Level ◽

Negative Bold

Functional magnetic resonance imaging (fMRI) techniques are based on the assumption that changes in spike activity are accompanied by modulation in the blood oxygenation level—dependent (BOLD) signal. In addition to conventional increases in BOLD signals, sustained negative BOLD signal changes are occasionally observed and are thought to reflect a decrease in neural activity. In this study, the source of the negative BOLD signal was investigated using T2*-weighted BOLD and cerebral blood volume (CBV) techniques in isoflurane-anesthetized cats. A positive BOLD signal change was observed in the primary visual cortex (area 18) during visual stimulation, while a prolonged negative BOLD change was detected in the adjacent suprasylvian gyrus containing higher-order visual areas. However, in both regions neurons are known to increase spike activity during visual stimulation. The positive and negative BOLD amplitudes obtained at six spatial-frequency stimuli were highly correlated, and negative BOLD percent changes were approximately one third of the postitive changes. Area 18 with positive BOLD signals experienced an increase in CBV, while regions exhibiting the prolonged negative BOLD signal underwent a decrease in CBV. The CBV changes in area 18 were faster than the BOLD signals from the same corresponding region and the CBV changes in the suprasylvian gyrus. The results support the notion that reallocation of cortical blood resources could overcome a local demand for increased cerebral blood flow induced by increased neural activity. The findings of this study imply that caution should be taken when interpreting the negative BOLD signals as a decrease in neuronal activity.

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Blood oxygenation level dependent (BOLD) signal response to progressive shortening of the rest period during activation of the visual cortex

NeuroImage ◽

10.1016/s1053-8119(96)80284-9 ◽

1996 ◽

Vol 3 (3) ◽

pp. S282 ◽

Cited By ~ 3

Author(s):

S. Kollias ◽

X. Golay ◽

D. Meier ◽

P. Boesiger ◽

A. Valavanis

Keyword(s):

Visual Cortex ◽

Rest Period ◽

Blood Oxygenation Level Dependent ◽

Blood Oxygenation ◽

Bold Signal ◽

Blood Oxygenation Level ◽

Oxygenation Level ◽

Signal Response

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

Cephalalgia ◽

10.1177/0333102414566860 ◽

2015 ◽

Vol 35 (11) ◽

pp. 1025-1030 ◽

Cited By ~ 25

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.

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

American Journal of Psychiatry ◽

10.1176/ajp.155.3.434 ◽

1998 ◽

Vol 155 (3) ◽

pp. 434-436 ◽

Cited By ~ 45

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

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Widespread and intense BOLD changes during brief focal electrographic seizures

Neurology ◽

10.1212/01.wnl.0000204232.37720.a4 ◽

2006 ◽

Vol 66 (7) ◽

pp. 1049-1055 ◽

Cited By ~ 59

Author(s):

E. Kobayashi ◽

C. S. Hawco ◽

C. Grova ◽

F. Dubeau ◽

J. Gotman

Keyword(s):

Blood Oxygenation Level Dependent ◽

Blood Oxygenation ◽

Angular Gyrus ◽

Temporal Region ◽

Bold Signal ◽

Hemodynamic Response Function ◽

Focal Seizures ◽

Blood Oxygenation Level ◽

Oxygenation Level ◽

Electrographic Seizures

Background: Combined recording of EEG and fMRI has shown changes in blood oxygenation level dependent (BOLD) signal during focal interictal epileptic spikes. Due to difficult assessment of seizures inside the scanner little is known about BOLD changes during seizures.Objectives: To describe BOLD changes related to brief focal electrographic seizures in a patient with right temporo-parietal gray matter nodular heterotopia.Methods: The patient underwent two EEG-fMRI sessions during which several focal seizures were recorded. EEG was acquired continuously during scanning and seizure timing was used for statistical analysis. Functional maps were thresholded to disclose positive (activation) and negative (deactivation) BOLD changes.Results: Twenty-five focal electrographic seizures were analyzed, consisting of runs of polyspikes lasting 2 to 6 s in the right temporal region. Activation included a large volume, involving the heterotopia and the abnormal temporo-parietal cortex overlying the nodule, with a clear maximum over the angular gyrus. Deactivation was bilateral and maximum in the occipital regions. The hemodynamic response function showed a return to baseline of the BOLD signal 30 s after seizure end.Conclusions: The brief focal seizures resulted in high amplitude and widespread blood oxygenation level dependent (BOLD) responses taking 30 s to return to baseline. This suggests that such brief events could have important behavioral consequences despite absent overt manifestations. A clear focal BOLD peak was found at some distance from the main EEG discharge, raising the possibility that the seizure could have started in a region that did not generate a visible EEG change despite its superficial location.

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Blood oxygenation level-dependent (BOLD) total and extravascular signal changes and ΔR 2 * in human visual cortex at 1.5, 3.0 and 7.0 T

NMR in Biomedicine ◽

10.1002/nbm.1552 ◽

2010 ◽

Vol 24 (1) ◽

pp. 25-34 ◽

Cited By ~ 54

Author(s):

Manus J. Donahue ◽

Hans Hoogduin ◽

Peter C. M. van Zijl ◽

Peter Jezzard ◽

Peter R. Luijten ◽

...

Keyword(s):

Visual Cortex ◽

Blood Oxygenation Level Dependent ◽

Blood Oxygenation ◽

Human Visual Cortex ◽

Blood Oxygenation Level ◽

Oxygenation Level ◽

Signal Changes

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Dynamic metabolic changes in human visual cortex in regions with positive and negative blood oxygenation level-dependent response

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x18795426 ◽

2018 ◽

Vol 39 (11) ◽

pp. 2295-2307 ◽

Cited By ~ 1

Author(s):

Miguel Martínez-Maestro ◽

Christian Labadie ◽

Harald E Möller

Keyword(s):

Visual Cortex ◽

Tricarboxylic Acid Cycle ◽

Blood Oxygenation Level Dependent ◽

Blood Oxygenation ◽

Metabolic Changes ◽

Resonance Spectroscopy ◽

Bold Response ◽

Full Field ◽

Blood Oxygenation Level ◽

Oxygenation Level

Dynamic metabolic changes were investigated by functional magnetic resonance spectroscopy (fMRS) during sustained stimulation of human primary visual cortex. Two established paradigms, consisting of either a full-field or a small-circle flickering checkerboard, were employed to generate wide-spread areas of positive or negative blood oxygenation level-dependent (BOLD) responses, respectively. Compared to baseline, the glutamate concentration increased by 5.3% ( p = 0.007) during activation and decreased by −3.8% ( p = 0.017) during deactivation. These changes were positively correlated with the amplitude of the BOLD response ( R = 0.60, p = 0.002) and probably reflect changes of tricarboxylic acid cycle activity. During deactivation, the glucose concentration decreased by −7.9% ( p = 0.025) presumably suggesting increased consumption or reduced glucose supply. Other findings included an increased concentration of glutathione (4.2%, p = 0.023) during deactivation and a negative correlation of glutathione and BOLD signal changes ( R = −0.49, p = 0.012) as well as positive correlations of aspartate ( R = 0.44, p = 0.035) and N-acetylaspartylglutamate ( R = 0.42, p = 0.035) baseline concentrations with the BOLD response. It remains to be shown in future work if the observed effects on glutamate and glucose levels deviate from the assumption of a direct link between glucose utilization and regulation of blood flow or support previous suggestions that the hemodynamic response is mainly driven by feedforward release of vasoactive messengers.

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Optogenetic fMRI Sheds Light on the Neural Basis of the BOLD Signal

Journal of Neurophysiology ◽

10.1152/jn.00535.2010 ◽

2010 ◽

Vol 104 (4) ◽

pp. 1838-1840 ◽

Cited By ~ 5

Author(s):

Helen. S. Palmer

Keyword(s):

Magnetic Resonance Imaging ◽

Blood Oxygenation Level Dependent ◽

Blood Oxygenation ◽

Bold Signal ◽

Functional Magnetic Resonance ◽

Resonance Imaging ◽

Neural Basis ◽

Bold Responses ◽

Blood Oxygenation Level ◽

Oxygenation Level

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is widely used as a measure of neuronal activity, despite an incomplete understanding of the hemodynamic and neural bases for BOLD signals. Recent work by Lee and colleagues investigated whether activating genetically specified neurons elicits BOLD responses. Integrating optogenetic control of specific cells and fMRI showed that stimulating excitatory neurons triggers a positive BOLD signal with conventional kinetics locally and delayed weaker BOLD signals distally.

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