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Is optical imaging spectroscopy a viable measurement technique for the investigation of the negative BOLD phenomenon? A concurrent optical imaging spectroscopy and fMRI study at high field (7 T).

Kennerley AJ, Mayhew JE, Boorman L, Zheng Y, Berwick J - Neuroimage (2012)

Bottom Line: Often accompanying positive BOLD fMRI signal changes are sustained negative signal changes.These experiments suggested that the negative BOLD signal in response to whisker stimulation was a result of an increase in deoxy-haemoglobin and reduced multi-unit activity in the deep cortical layers.Furthermore their study utilised a homogeneous tissue model in which is predominantly sensitive to haemodynamic changes in more superficial layers.

View Article: PubMed Central - PubMed

Affiliation: Centre for Signal Processing in Neuroimaging and Systems Neuroscience (SPiNSN), Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK. A.J.Kennerley@shef.ac.uk

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Correlation plot of predicted negative BOLD against measured fMRI negative BOLD. Negative data points from the mean times series across animals are plotted for both the 2D-OIS homogeneous (blue) and heterogeneous (red) tissue model time series predictions. For both tissue models there is a high correlation between prediction and measured BOLD (0.95). However, the gradient of heterogeneous tissue model (1.08) predictions overlap the 1:1 relationship, in contrast to the gradient of the homogeneous tissue model (0.71) which consistently under-estimates the magnitude of the BOLD response.
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f0035: Correlation plot of predicted negative BOLD against measured fMRI negative BOLD. Negative data points from the mean times series across animals are plotted for both the 2D-OIS homogeneous (blue) and heterogeneous (red) tissue model time series predictions. For both tissue models there is a high correlation between prediction and measured BOLD (0.95). However, the gradient of heterogeneous tissue model (1.08) predictions overlap the 1:1 relationship, in contrast to the gradient of the homogeneous tissue model (0.71) which consistently under-estimates the magnitude of the BOLD response.

Mentions: Nevertheless, using the prior that neuronal activity driving the negative BOLD is predominantly in the deeper cortical layers we can bias the spectroscopy algorithm to be more sensitive to changes in the deeper layers of the cortex. Fig. 7 shows that the heterogeneous model gives a better prediction of the time series of negative fMRI-BOLD signal. This can be seen from the fact that the heterogeneous model gradient is very close to 1. The correlation of the prediction to measurements is both very high (with different tissue models) which implies that the effect of the heterogeneous tissue model is primarily one of scaling.


Is optical imaging spectroscopy a viable measurement technique for the investigation of the negative BOLD phenomenon? A concurrent optical imaging spectroscopy and fMRI study at high field (7 T).

Kennerley AJ, Mayhew JE, Boorman L, Zheng Y, Berwick J - Neuroimage (2012)

Correlation plot of predicted negative BOLD against measured fMRI negative BOLD. Negative data points from the mean times series across animals are plotted for both the 2D-OIS homogeneous (blue) and heterogeneous (red) tissue model time series predictions. For both tissue models there is a high correlation between prediction and measured BOLD (0.95). However, the gradient of heterogeneous tissue model (1.08) predictions overlap the 1:1 relationship, in contrast to the gradient of the homogeneous tissue model (0.71) which consistently under-estimates the magnitude of the BOLD response.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368428&req=5

f0035: Correlation plot of predicted negative BOLD against measured fMRI negative BOLD. Negative data points from the mean times series across animals are plotted for both the 2D-OIS homogeneous (blue) and heterogeneous (red) tissue model time series predictions. For both tissue models there is a high correlation between prediction and measured BOLD (0.95). However, the gradient of heterogeneous tissue model (1.08) predictions overlap the 1:1 relationship, in contrast to the gradient of the homogeneous tissue model (0.71) which consistently under-estimates the magnitude of the BOLD response.
Mentions: Nevertheless, using the prior that neuronal activity driving the negative BOLD is predominantly in the deeper cortical layers we can bias the spectroscopy algorithm to be more sensitive to changes in the deeper layers of the cortex. Fig. 7 shows that the heterogeneous model gives a better prediction of the time series of negative fMRI-BOLD signal. This can be seen from the fact that the heterogeneous model gradient is very close to 1. The correlation of the prediction to measurements is both very high (with different tissue models) which implies that the effect of the heterogeneous tissue model is primarily one of scaling.

Bottom Line: Often accompanying positive BOLD fMRI signal changes are sustained negative signal changes.These experiments suggested that the negative BOLD signal in response to whisker stimulation was a result of an increase in deoxy-haemoglobin and reduced multi-unit activity in the deep cortical layers.Furthermore their study utilised a homogeneous tissue model in which is predominantly sensitive to haemodynamic changes in more superficial layers.

View Article: PubMed Central - PubMed

Affiliation: Centre for Signal Processing in Neuroimaging and Systems Neuroscience (SPiNSN), Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK. A.J.Kennerley@shef.ac.uk

Show MeSH
Related in: MedlinePlus