Neural bases of human working memory

Working memory is the memory system that allows us to briefly keep informat ion active, often so we can operate on it. Studies with rhesus monkeys firs t established that this system is partly mediated by neural mechanisms in t he prefrontal cortex. Recently, there has been a substantial effort to stud y the neural bases of working memory in humans, using neuroimaging techniqu es such as positron emission tomography and functional magnetic resonance i maging. Some of the initial neuroimaging studies with humans focused on the neural mechanisms that mediate our ability to keep spatial information act ive. These results indicated that human spatial working memory is partly me diated by regions in parietal and prefrontal cortex. Subsequent research ha s shown that a different neural system is involved when people store object (rather than spatial) information, a difference similar to that found in m onkeys.