The neural correlates of updating information in verbal working memory

The aim of the present study was to re-examine cerebral areas subserving th e updating function of the central executive with a running span task requi ring subjects to watch strings of consonants of unknown length and then to recall serially a specific number of recent items. In order to dissociate m ore precisely the updating process from the storage function, a four-item i nstead of a six-item memory load was used, contrary to our previous study ( Salmon et al., 1996). In addition, a serial recall procedure was preferred to a recognition procedure in order to suppress the use of visuospatial str ategies. The most significant increase of rCBF occurred in the left frontop olar cortex (Brodmann's area 10), spreading to the left middle frontal (Bro dmann's area 46). Results suggest that frontopolar activation underlies an updating process in working memory.