Thinking...
Central Processing Unit :-) Cognition.
by thinking and exersising your brain.
reason logically, can perform operations,
Of or pertaining to the chin; genian; as, the mental nerve; the mental region., A plate or scale covering the mentum or chin of a fish or reptile., Of or pertaining to the mind; intellectual; as, mental faculties; mental operations, conditions, or exercise.
mental image
cognition
cognition
A "mental thing" would be something that is in your mind, or that deals with your mental state.
Cognitive is the medical term meaning related to mental activities associated with thinking, learning, and memory.
The most common method of determining mental ill health is by noting the emotions, thinking, and behaviors that are out of character for an individual, or by evaluating a set of thinking, emotions, and behaviors to see if they conform to a particular profile of mental ill health, such as psychosis.
Mental and physical fitness