2002/01/01 by J. Daniel Ragland, Bruce I. Turetsky, Ruben C. Gur +9 · 3 citations
Neuroscience · #Functional Brain Connectivity Studies #Motor Control and Adaptation #Neural and Behavioral Psychology Studies
paper · doi:10.1037/0894-4105.16.3.370
openalex publication_date 2002/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
n-back letter and fractal tasks were administered to 11 participants during functional magnetic resonance imaging to test process specificity theories of prefrontal cortex (PFC) function and assess task validity. Tasks were matched on accuracy, but fractal n-back responses were slower and more conservative. Maintenance (1-back minus 0-back) activated inferior parietal and dorsolateral PFC, with additional activation in right ventrolateral PFC during letter n-back and left lingual gyrus during fractal n-back. Maintenance plus manipulation (2-back minus 0-back) activated inferior parietal, Broca's area, insula, and dorsolateral and ventral PFC, with greater right dorsolateral PFC activation for letter n-back. Manipulation only (2-back minus 1-back) produced additional and equivalent dorsolateral PFC and anterior cingulate activation in both tasks. Results support fractal n-back validity and indicate substantial overlap in working memory functions of dorsal and ventral PFC.