This study tested the mechanism of the ventromedial prefrontal cortex (vmPFC) in representing schemata, be it excitatory or inhibitory. Participants were administered a behavioural task distinguishing their ability to activate a relevant schema from their ability to inhibit an irrelevant schema. Healthy participants were highly accurate throughout the task, indicating proficiency in both abilities. However, older adults demonstrated a need for greater cognitive resources to inhibit a previously relevant schema. Non-confabulating patients with vmPFC lesions acted similarly to control participants, while patients with vmPFC lesions with either current or prior demonstration of confabulation performed abnormally. Specifically, their inability to inhibit irrelevant schemata was more severe than their inability to activate a relevant one. The results suggest that the nature of vmPFC damage leading to confabulation may also be responsible for erroneous schema representations. A sub-region of the vmPFC is proposed to underlie the representation of schemata through semantic lateral inhibition.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/33216 |
| Date | 20 November 2012 |
| Creators | Ghosh, Vanessa |
| Contributors | Gilboa, Asaf |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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