Localized brain activation by selective tasks improves specific cognitive functions in humans

Neuroimaging studies have identified cognitive tasks that can selectively a ctivate specific parts of the brains. However, the subsequent effect of loc alized brain activation on the cognitive functioning remains unclear. We di scovered that after being engaged in the novel picture encoding task to act ivate hippocampus for 2 min, individuals demonstrated better memory, but no t motor function. Similarly, after performing the finger sequencing task to activate the primary motor cortex, individuals showed improvement in motor function, but not in memory. These double dissociation results suggest tha t when we selectively activate specific part of the brain, the cognitive fu nction mediated by that particular region but not the others can consequent ly be improved. (C) 2000 Elsevier Science Ireland Ltd. All Fights reserved.