The relationship between electrophysiological and hemodynamic measures of neural activity varies across picture naming tasks: A multimodal magnetoencephalography-functional magnetic resonance imaging study

Different neuroimaging methods can yield different views of taskdependent
neural engagement. Studies examining the relationship between
electromagnetic and hemodynamic measures have revealed correlated
patterns across brain regions but the role of the applied stimulation or
experimental tasks in these correlation patterns is still poorly understood.
Here, we evaluated the across-tasks variability of MEG-fMRI relationship using
data recorded during three distinct naming tasks (naming objects and actions
from action images, and objects from object images), from the same set of
participants. Our results demonstrate that the MEG-fMRI correlation pattern
varies according to the performed task, and that this variability shows distinct
spectral profiles across brain regions. Notably, analysis of the MEG data
alone did not reveal modulations across the examined tasks in the timefrequency
windows emerging from the MEG-fMRI correlation analysis. Our
results suggest that the electromagnetic-hemodynamic correlation could
serve as a more sensitive proxy for task-dependent neural engagement in
cognitive tasks than isolated within-modality measures.