Temporal Dynamics and Neural Basis of Cognitive Control in Associative Learning Processes
Gray, Phillip J.
Executive control of cognitive functioning involves high level coordination of multiple cognitive processes. Cognitive control employs attentional, decision making, and coordinative functions in managing the multitude of information the human brain processes. Control mechanisms coordinate lower-level sensory and motor processing along a common theme or internal goal. The neural circuitry of cognitive control is spread throughout the brain; but the anterior cingulate cortex and the prefrontal cortex are particularly important. Using behavioral and imaging methods to probe cerebral organization, this study investigates the temporal dynamics of the functional segregation of cognitive control at the basis of associative learning processes. Functional magnetic resonance imaging (fMRI) tracked blood-oxygen-level-dependent (BOLD) signaling in anterior cingulate cortex (ACC), middle frontal gyrus (MFG), and hippocampus during performance of an associative learning task in which participants were asked to encode and retrieve nine object-location association pairs. Analysis of imaging data shows a significant percent signal decrease in both anterior cingulate cortex and middle frontal gyrus between early and late periods of encoding and retrieval. Hippocampal signal did not show significant changes over time; in this working memory task, activity in the hippocampus is required in order to encode and retrieve associations at any time in the task. The data show that cognitive control is a dynamic process in the brain, implemented by a distributed neural network. Understanding time courses of network-level interaction in cognitive control has implications for disorders like schizophrenia.
vi, 33 p.
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