Agents for preventing and/or treating higher brain dysfunctions

摘要

(wherein R¹, R² and R³ are the same or different, and represent a hydrogen atom, lower alkyl, lower alkenyl or lower alkynyl; R⁴ represents cycloalkyl, -(CH₂)_n-R⁵ or a group represented by the above formula (II); and X¹ and X² are the same or different, and represent an oxygen atom or a sulfur atom) The present invention provides, for example, agents for preventing and/or treating higher brain dysfunction comprising, as an active ingredient, a xanthine derivative represented by the above formula (I) or a pharmaceutically acceptable salt thereof.