The Role of the Anterior Prefrontal Cortex in Human Cognition

Complex problem-solving and planning depend on holding a main goal in mind while pursuing concurrent subgoals — a process the authors term branching — and although the fronto-polar prefrontal cortex (FPPC) is especially well developed in humans compared with other primates, its specific cognitive role had remained poorly understood. Using functional MRI with a factorial design that crossed working memory demands with dual-task attentional demands, the study isolated the regions engaged specifically by the integration of the two rather than by either process alone. Bilateral fronto-polar regions were selectively activated in the branching condition and showed no comparable response to working memory or dual-task performance on their own, and additional analyses ruled out mere task difficulty as an explanation. The results establish that this evolutionarily expanded region of the human frontal lobe mediates the ability to keep a pending goal available while exploring secondary goals, a mechanism fundamental to planning and reasoning.