The fMRI study showed that, during the viewing of angry faces, the activity of a structure called the insula, involved in the response to unpleasant situations, depended on which version of the CREB1 gene a participant inherited.

“We were surprised to see that variation in the CREB1 gene would account for more than 20 percent of the difference in how healthy participants weighed different options and expressed specific preferences,”

what happens to CREB1 gene when you are acting in a play that requires different moods?

probably this belongs to the other 80%