Cortical networks relating to arousal are differentially coupled to neural activity and hemodynamics

Even in the absence of specific sensory input or a behavioral task, the brain produces structured patterns of activity. This organized activity has been shown to be modulated by changes in arousal. Here, we use wide-field voltage imaging to establish the relationship between cortical network activity and arousal in spontaneously behaving head-fixed mice expressing the voltage sensitive fluorescent FRET sensor Butterfly 1.2. This approach allowed us to simultaneously image hemodynamic and voltage activity, and then compare fMRI analogous activity changes to the direct cortical voltage activity in relation to arousal and movement. Arousal and facial movements were assessed through analysis of face video recordings. We find that changes in pupil diameter were differentially coupled to hemodynamics and cortical voltage activity in a regionally and frequency specific way. Further this coupling changed between periods of spontaneous facial movements, and periods of rest. Our results indicate that while fMRI-like hemodynamic signals show strong relations to behavior and arousal, these relations are distinct from those shown by brain voltage activity.