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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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Direct comparison of haemodynamic time series (HbT and Hbr) from a) the whisker barrel region and b) the surrounding cortex to equivalent data from Boorman et al. (2010). Data has been normalised as Boorman et al. (2010) did not analyse the 2D-OIS data with improved tissue models. Furthermore, in that study fMRI and 2D-OIS were not performed concurrently so one could argue that the measured haemodynamics did not lead to a negative BOLD signal. We find that our normalised haemodynamic responses show similar transients to their 2D-OIS data. In the current study we have explicitly shown that such haemodynamic changes lead to a sustained negative BOLD signal, and thus our data adds more support to their hypothesis that the deep layer negative BOLD is driven by deep layer decreases in neuronal activity.
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f0030: Direct comparison of haemodynamic time series (HbT and Hbr) from a) the whisker barrel region and b) the surrounding cortex to equivalent data from Boorman et al. (2010). Data has been normalised as Boorman et al. (2010) did not analyse the 2D-OIS data with improved tissue models. Furthermore, in that study fMRI and 2D-OIS were not performed concurrently so one could argue that the measured haemodynamics did not lead to a negative BOLD signal. We find that our normalised haemodynamic responses show similar transients to their 2D-OIS data. In the current study we have explicitly shown that such haemodynamic changes lead to a sustained negative BOLD signal, and thus our data adds more support to their hypothesis that the deep layer negative BOLD is driven by deep layer decreases in neuronal activity.

Mentions: Boorman et al. (2010) hypothesised that the deep layer negative BOLD was driven by deep layer decreases in neuronal activity. However, in that study fMRI and 2D-OIS were not performed concurrently. In that study they did concurrent electrophysiology and 2D-OIS and compared data to coronal fMRI from a different set of subjects. We found that our normalised haemodynamic responses showed very similar transients to their 2D-OIS data (Fig. 6). As we have now explicitly shown that such haemodynamic changes lead to a negative BOLD signal, the current data adds more support to their proposal regarding the neuronal origin of the negative BOLD.


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)

Direct comparison of haemodynamic time series (HbT and Hbr) from a) the whisker barrel region and b) the surrounding cortex to equivalent data from Boorman et al. (2010). Data has been normalised as Boorman et al. (2010) did not analyse the 2D-OIS data with improved tissue models. Furthermore, in that study fMRI and 2D-OIS were not performed concurrently so one could argue that the measured haemodynamics did not lead to a negative BOLD signal. We find that our normalised haemodynamic responses show similar transients to their 2D-OIS data. In the current study we have explicitly shown that such haemodynamic changes lead to a sustained negative BOLD signal, and thus our data adds more support to their hypothesis that the deep layer negative BOLD is driven by deep layer decreases in neuronal activity.
© Copyright Policy
Related In: Results  -  Collection

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

f0030: Direct comparison of haemodynamic time series (HbT and Hbr) from a) the whisker barrel region and b) the surrounding cortex to equivalent data from Boorman et al. (2010). Data has been normalised as Boorman et al. (2010) did not analyse the 2D-OIS data with improved tissue models. Furthermore, in that study fMRI and 2D-OIS were not performed concurrently so one could argue that the measured haemodynamics did not lead to a negative BOLD signal. We find that our normalised haemodynamic responses show similar transients to their 2D-OIS data. In the current study we have explicitly shown that such haemodynamic changes lead to a sustained negative BOLD signal, and thus our data adds more support to their hypothesis that the deep layer negative BOLD is driven by deep layer decreases in neuronal activity.
Mentions: Boorman et al. (2010) hypothesised that the deep layer negative BOLD was driven by deep layer decreases in neuronal activity. However, in that study fMRI and 2D-OIS were not performed concurrently. In that study they did concurrent electrophysiology and 2D-OIS and compared data to coronal fMRI from a different set of subjects. We found that our normalised haemodynamic responses showed very similar transients to their 2D-OIS data (Fig. 6). As we have now explicitly shown that such haemodynamic changes lead to a negative BOLD signal, the current data adds more support to their proposal regarding the neuronal origin of the negative BOLD.

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