Temporal Dynamics and Neural Basis of Cognitive Control in Associative Learning Processes
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Authors
Gray, Phillip J.
Issue Date
2008
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
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.
Description
vi, 33 p.
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