Functional-anatomic exploration of cognitive control

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Presented with changing task goals, healthy young adults can flexibly process and expand upon task relevant information in a controlled manner. At a functional-anatomic level, such cognitive control is associated with selective recruitment of specific prefrontal regions that interact with posterior cortical regions to constrict task-appropriate representations and drive task performance. The present proposal begins an exploration of how these processes develop in childhood, change in advanced aging, and what the significance of their developmental stage is to behavioral task performance. Two hypotheses are explored using this "Life span" approach. First, we predict that cognitive control develops in children concurrent with the ability to recruit frontal regions for task performance. Second, we predict that cognitive control breaks down in older adults when frontal regions are recruited, but in a non-selective manner. A further goal of this proposal is to explore the cognitive consequences of non-selective recruitment in advanced aging. By developing and using cognitive tests sensitive to component processes associated with cognitive control, the behavioral consequences of the emergence of cortical control processes and their breakdown will be explored. In addition, methodological challenges that confront between-group analyses including those surrounding possible anatomic (with development and atrophy), hemodynamic, and performance differences will be explored. Specific aims are (1) to refine methods and determine boundary conditions for making functional-anatomic comparisons across the life span including children, young adults, and older adults, (2) to explore activation patterns within frontal cortex during controlled verbal processing tasks across children, young adults, and older adults using a verbal task battery, (3) to measure, in individual subjects, their capacity for cognitive-control and associate such abilities with their absolute level of frontal recruitment and selectivity of frontal recruitment. If completed, the present proposal will provide (1) methods for functional- anatomic description across the life span from childhood to advanced aging, (2) a corpus of functional- anatomic findings describing developmental change with a particular focus on prefrontal cortex and other structures associated with cognitive control, and (3) data relating these functional-anatomic changes with behavioral correlates of cognitive control.