I can do that, I am curious: Why is that better?

I also want to test whether facial muscle activity is stronger during the experiment trials when compared to baseline. I have measured two muscles. Is it correct that in this case, I would do a mixed-model logistic regression where I predict the time period (baseline vs. experiment) from the activity of muscle one and activity of muscle 2.

Thanks a lot for the extensive answer! The emotion assessment is actually also continuous (0-10, where 0 is most negative and 10 most positive) so a logistic regression is not needed. If I do two mixed linear regressions to test both directions, I will have doubled my chances to find a significant effect so I need to correct for multiple comparisons correct?

Adjusted! It is indeed a rating that follows after the button press and therefore also after the measurement of facial muscle activity.

Ah okay. I took that information from websites that say that in regression we test how x influences y and that changing the order of the variables leads to different results. I think that the order is not clear in my case. Does the subjective judgment of valence come first or does the physiological reaction of valence come first (James-Lange theory). I feel like I would need to make a decision (assume one theory but not the other) when using regression, whereas a t-test would just test if there is a significant difference.