Sometimes, in meetings, I have to scribble down a non-work-related thought or question to hunt down later just to get it out of my head so I can pay attention to what’s going on in person. I use square checkboxes for these. Circles are for work-related tasks.
A friend of ours coined the term “hotbrain” for this and it is where I am right now. A fixation on something that makes my mind churn on a solution in the background, and the only way to keep functioning is to lasso it on paper.