Cubism Love Manga Summary
From Aerandria Scans:
Noriko is caught up in an accident while she is going to her track and field competition. When she opens her eyes, there is the young doctor Shinoda who seems very concerned about her. She is attracted to his child-like smile, but from his lips, she learns a shocking truth - in the accident, Noriko has lost her physical body and what remains is only a brain, stuck in a little black box?!
Note: The side stories in volume 1, 2 & 3 are written in novel format.