Correcting Task fMRI Signals for Variability in Baseline CBF Improves BOLD-Behavior Relationships: A Feasibility...

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Physiology

Background:

• Blood Oxygen Level Dependent (BOLD) functional MRI (fMRI) is sensitive to baseline physiological factors like cerebral blood flow (CBF).
• Aging alters baseline CBF, potentially confounding interpretations of age-related BOLD signal changes.
• Accurate interpretation of BOLD signals requires accounting for individual physiological variations.

Purpose of the Study:

• To develop and validate a methodology combining task fMRI and arterial spin labeling (ASL) to sensitize task-induced BOLD activity.
• To improve the specificity and sensitivity of BOLD signals by covarying out baseline CBF in an aging model.
• To investigate the impact of this BOLD signal correction on BOLD-behavior relationships.

Main Methods:

• Recruited younger and older healthy participants (11 and 13, respectively).
• Acquired ASL and overt language task fMRI data (semantic category member generation).
• Measured in-scanner language performance to assess BOLD-behavior associations.

Main Results:

• The developed correction approach effectively enhanced BOLD signal specificity and sensitivity in both age groups.
• Correction strengthened the statistical association between task BOLD activity and behavioral performance.
• Older adults exhibited delayed language task activity, potentially due to reduced vessel compliance.

Conclusions:

• Correcting task fMRI signals by covarying out baseline CBF is recommended, particularly for inter-group comparisons with differing neurovascular properties.
• The proposed multi-modal ASL-BOLD fMRI methodology can be readily integrated into data processing pipelines for more accurate BOLD activation maps.
• This approach offers improved predictability of behavior compared to uncorrected or normalized methods, though further validation is needed.