The following article review the issues concerning neuronal basis of attention. Attention is not treated by author as a single entity but as a name given to a finite set of brain processes interacting with each other and influencing other brain processes in the performance of perceptual, motor and cognitive actions. At the most general level one could state that function of attention is to allow and to maintain specific reaction of the organism in the face of incoming information. In this meaning attention system of the brain is cooperating with sensory systems by selecting information based on its semantic meaning. From the other hand, attention system serves as a mechanism, decides about the priorities of motor activity and controls motor planning, providing the efficient response to the environmental changes.