The uniquely human ability to rapidly learn novel tasks from instructions is extremely important in everyday life, and yet its evolutionary origin and basis in the brain remain mysteries. In order to address these gaps in scientific knowledge, comparative human-monkey studies were consulted to predict the human brain areas involved in rapid instructed task learning (RITL). These predictions were tested using functional MRI (fMRI), magnetoencephalography (MEG), and a novel cognitive paradigm developed to systematically investigate the neural basis of RITL for the first time. In accordance with cross-species neuroanatomical differences, anterior prefrontal cortex (aPFC), anterior temporal lobe (aTL), dorsolateral prefrontal cortex (DLPFC), and posterior parietal cortex (PPC) were found to be involved in RITL. DLPFC and PPC formed a network involved in loading individual task semantics into working memory, while aPFC and aTL formed a network involved in integrating semantics in preparation for task performance. Both networks supported novel task set formation, which occurred in a bottom-up manner (semantic loading, then integration), and practiced task set retrieval, which occurred in a top-down manner (integration retrieval, then semantic loading). These findings suggest that RITL relies upon semantic loading by DLPFC and PPC, but that aPFC and aTL support semantic integration both dynamically during RITL and from long-term memory after extensive practice. More broadly, the findings suggest RITL is enabled in humans via a combination of enhanced symbolic processing (language), enhanced working memory manipulation (aPFC), and enhanced integrated semantic representation (aTL).
The present document begins with a broad overview of RITL and related topics, such as its relation to animal cognition, other forms of learning, and cognitive control. These topics support several novel hypotheses regarding RITL and its likely basis in the brain. The fMRI study is then presented, verifying many of the hypotheses developed in the previous section. The MEG study is reported next, clarifying many of the questions about timing and causality suggested by the fMRI results. Finally, a general discussion integrates the results from both studies, expanding conclusions with an overview of brain connectivity findings, cross-species differences, and the role of neural hierarchies in RITL and cognition generally.
Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-07152009-145850 |
Date | 30 September 2009 |
Creators | Cole, Michael William |
Contributors | Anthony Wagner, Walter Schneider, Mark Wheeler, Marc Sommer, Julie Fiez, Raymond Cho |
Publisher | University of Pittsburgh |
Source Sets | University of Pittsburgh |
Language | English |
Detected Language | English |
Type | text |
Format | application/pdf |
Source | http://etd.library.pitt.edu/ETD/available/etd-07152009-145850/ |
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