I noticed quite a change in mood when I started reintroducing foods with choline into my diet. Of course, some of those foods have some other nutrients that are harder to get. Eggs and beef were the main sources I targeted.

Obviously, overall diet, sleep, exercise, etc. etc. matters as well.

I really wouldn't read too much into MR spectroscopy studies.

MRS is an extremely blunt instrument and only serves to line peoples CVs with scientific sounding publications.