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The negative BOLD signal unmasked.
1Smith-Kettlewell Eye Research Institute, 2318 Fillmore Street, San Francisco, CA 94115, USA.
Neuron
|December 24, 2002
Summary
The negative BOLD response (NBR) in brain imaging is linked to reduced blood flow and energy consumption. Researchers conclude NBR primarily results from active neuronal inhibition.
Area of Science:
- Neuroimaging
- Cognitive Neuroscience
- Brain Activity
Background:
- Functional magnetic resonance imaging (fMRI) studies often reveal cortical regions responding inversely to stimuli.
- This phenomenon, termed the negative BOLD response (NBR), has been observed but its underlying mechanisms remain debated.
Discussion:
- Shmuel et al. demonstrate a spatial and temporal correlation between NBR and decreased cerebral blood flow.
- By integrating BOLD and blood flow data, the study models cortical energy consumption.
Key Insights:
- The NBR is not merely an artifact but a physiologically relevant signal.
- The findings strongly suggest that active neuronal inhibition is the principal driver of the NBR.
- This challenges previous assumptions and offers a refined understanding of neural processing.
Outlook:
- Further research can explore the specific inhibitory circuits involved in NBR.
- Investigating NBR across different cognitive tasks may reveal its broader role in brain function.
- This work provides a foundation for more accurate interpretations of fMRI data.