In the current work, the distinction between priming for associatively-related (AR) and unassociated semantically-related (SR) words is examined. Specifically, whereas associatively-related words demonstrate strong and robust priming effects when presented within the context of lexical-level tasks, generation of significant SR priming appears to require execution of an explicitly semantic task. This apparent levels-of-processing effect, if reflected in the neural-level implementation, would suggest that the mechanisms underlying priming may be localized to spatially and functionally distinct cerebral regions. In the first part of the thesis, an artifactual decision task (ADT) is developed and refined, which proved capable of producing strong immediate SR priming for auditorily presented words. Insertion of unrelated items between prime and target produced differential effects on priming, with AR targets exhibiting an interference effect that slowly diminished as more unrelated items were inserted. The nature of the underlying difference at the neural substrate level was subsequently examined in a PET imaging study, in which subjects performed an auditory ADT using both AR and SR words. Analysis of the cerebral blood flow patterns (CBF) using both simple contrasts, as well as partial least squares (PLS) analysis, found priming-related rCBF decreases in the left frontal regions, primarily within the inferior prefrontal cortex, and left-sided priming-related increases, localized primarily to the superior temporal gyrus, and the ventral temporal surface. Priming-related modulations were reflected by SR words, but not AR words. A behavioral PLS analysis demonstrated that an increase in both SR priming and AR interference effects was associated with increased activity with the extrastriate cortical regions, particularly on the left, suggesting a contribution of visual areas to both facilitatory and interference effects. The imaging findings are
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.85632 |
| Date | January 2005 |
| Creators | Nikelski, Erwin James |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002226978, proquestno: AAINR12918, Theses scanned by UMI/ProQuest. |
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