Limits...
BOLD-perfusion coupling during monocular and binocular stimulation.

Gauthier C, Hoge RD - Int J Biomed Imaging (2008)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Unité de Neuroimagerie Fonctionnelle, Institut Universitairy of Gériatrie de Montréal, Montreal, QC, Canada H3W 1W5.

ABSTRACT
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.

No MeSH data available.


Percent change (±SE in lighter shade of gray) in BOLD and CBFsignals in response to binocular and monocular stimulation. Responses evoked bybinocular stimulation are significantly greater than those produced bymonocular stimulation.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2266813&req=5

fig3: Percent change (±SE in lighter shade of gray) in BOLD and CBFsignals in response to binocular and monocular stimulation. Responses evoked bybinocular stimulation are significantly greater than those produced bymonocular stimulation.

Mentions: The bar graphs in Figure 3 show average percent changes in BOLDand flow signals within the V1 ROIs of all subjects. The average percent changein BOLD signal for monocular stimulation was 0.93±0.04, which was significantly (P < .05) less than the percentchange of 1.11 ± 0.05 observed during binocular stimulation. The percent flowincrease measured during monocular stimulation was 29 ± 2, also significantlyless than the percent change of 37 ± 2 observed during binocular stimulation. Expressedas a percent reduction in the response amplitude, withholding input from one ofthe two eyes resulted in a 16 ± 6% decrease in the BOLD response and 19 ± 9%decrease in the perfusion response.


BOLD-perfusion coupling during monocular and binocular stimulation.

Gauthier C, Hoge RD - Int J Biomed Imaging (2008)

Percent change (±SE in lighter shade of gray) in BOLD and CBFsignals in response to binocular and monocular stimulation. Responses evoked bybinocular stimulation are significantly greater than those produced bymonocular stimulation.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2266813&req=5

fig3: Percent change (±SE in lighter shade of gray) in BOLD and CBFsignals in response to binocular and monocular stimulation. Responses evoked bybinocular stimulation are significantly greater than those produced bymonocular stimulation.
Mentions: The bar graphs in Figure 3 show average percent changes in BOLDand flow signals within the V1 ROIs of all subjects. The average percent changein BOLD signal for monocular stimulation was 0.93±0.04, which was significantly (P < .05) less than the percentchange of 1.11 ± 0.05 observed during binocular stimulation. The percent flowincrease measured during monocular stimulation was 29 ± 2, also significantlyless than the percent change of 37 ± 2 observed during binocular stimulation. Expressedas a percent reduction in the response amplitude, withholding input from one ofthe two eyes resulted in a 16 ± 6% decrease in the BOLD response and 19 ± 9%decrease in the perfusion response.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Unité de Neuroimagerie Fonctionnelle, Institut Universitairy of Gériatrie de Montréal, Montreal, QC, Canada H3W 1W5.

ABSTRACT
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.

No MeSH data available.