Abstract: Working memory refers to a brain system that maintain a limited amount of information in an active state for a brief of time and manipulate that information necessary for such complex cognitive tasks as language comprehension, learning, and reasoning. Neuroimagingstudies on neural basis of human working memory indicated that: (1) there are different working memory systems with distinct neural implementation for verbal (localized more in the left hemisphere), spatial (localized more in the right hemisphere), visual or object information, and integrated information (localized in the right frontal lobe) ; (2) each system has three different functional components: (i) a pure storage component (localized more in the back of the brain), whose contents decay rapidly; (ii) a rehearsal component (localized more in the front of the brain), that can reactivate the rapidly decaying contents of the storage component; and (iii) an executive component (localized in the prefrontal cortex) that regulates the processing of the contents of working memory; (3) Prefrontal cortex plays an important role in both executive processes, such as attention and inhibition, task management, and integration of verbal and spatial information in working memory.

Key words: working memory, human brain, positron emission tomography (PET), functional magnetic resonance imaging (fMRI)