Times series in vasoreactivity

Hi everyone.
I'm working with cerebral vasoreactivity data and I'm interested in the analysis of the average signal of the white matter over time, because I'm not sure that my carbon dioxide inhalation system (vasoreactivity  mechanism) was working in order to write a designer matrix for each subject.
How can I do this?

You can use Utilities->ROI Signals Extractor to extract the time series.