Personalized Santa Hat Brain Youth T-Shirt. A happy brain wearing a Santa hat is a humorous winter holiday gift design for psychologists, neuroscientist, neurologists, neurosurgeons and medical students. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.