A developmental functional MRI study of spatial working memory

Functional magnetic resonance imaging (fMRI) was used to examine patterns o f cortical activity in children during performance of a spatial working mem ory task. Six children (8-10 years) and six adults (19-26 years) searched a linear array of four boxes for the appearance of a dot. In the visual bloc ks, participants made no response. In the motor blocks, participants were i nstructed to indicate the location of the dot on each trial using a button- press response. In the working memory blocks, participants were instructed to indicate at which location the dot had appeared 1 or 2 trials previously . Both children and adults showed activity in the left precentral and postc entral gyri, as well as the right cerebellum for the motor condition as com pared to the visual condition. Comparison of the memory and motor condition s revealed reliable activity in the right superior frontal gyrus (BA 8), ri ght dorsolateral prefrontal cortex (BA 10/46), right superior parietal cort ex, and bilateral inferior parietal cortex for both adults and children. Th ese results suggest that spatial working memory tasks activate very similar cortical regions for school-age children and adults. The findings differ f rom previous imaging studies of nonspatial working memory tasks in that the prefrontal activations observed in the current work tend to be more dorsal . Results are discussed in light of the significant behavioral performance differences observed between child and adult participants. (C) 1999 Academi c Press.