This is clipart converted and broken apart that has been released into the public domain because the document says so, and its from NASA, a USA government agency. The publication is called "The Brain in Space:" http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/The.Brain.in.Space.html スペース 科学 脳 58294main_The.Brain.in.Space-page-38-diagram-of-involuntary-reflex-action
A glossy sphere with reflen on black background. Esfera brillante con reflejo sobre fondo negro. 球 光沢紙 反射 光沢のある球 w/反射。反射と明るいフィールド。