Table 1.
Potential confounding factors affecting BOLD signal generation in MS studies and strategies to overcome them.
Source of fMRI signal | Confounding factors | Strategy to control for confounding factors |
---|---|---|
Neural signalling | Disease-related or intervention-related increases or decreases in brain activity | Simultaneous or delayed electrophysiological recording |
Neurovascular coupling | Disease-related or intervention-related effect on vascular response to changes of neural activity | Measure vascular reactivity (for example, with carbon dioxide challenge) |
Vascular compartment | Disease-related or intervention-related differences in baseline perfusion levels | Measure baseline perfusion Measure perfusion response to a task |