The question of the investigation of functions of prefrontal cortex is put in the article. The author supposes that this zone of the brain is responsible for several different psychological components. He suggests a special method of investigation of some of the components. The method consists in combined use of principle of dissociation and the analysis of psychological processes’ disorders in the view of their stages of realization. As a result of the research there were defined some psychological components which were responsible for programming, regulation and control of different stages of thinking. Several neuropsychological syndromes of the disturbances of programming, regulation and control of thinking were marked out. The syndromes represented interconnected combinations of the disorders of the components.