Abstract

Two projects are presented in this dissertation. First, we investigated the impact of false memories on the original trace and whether recovery of the original is possible. Second, we tested whether mnemonic discrimination for temporal duration is possible. Both projects incorporated fMRI techniques in order to implicate any potential neural correlates of these memory behaviors. Project One. To elicit false memories and study a potential recovery therefrom, thirty-five healthy, young adults performed multiple recognition memory tests where they were induced to make errors in a first test and then participants were tested again in a surprise, second test. These two tests allowed us to determine which memory error would be corrected, if any. Further, fMRI signal associated with the encoding and retrieval processes during the experiment allowed us to implicate the regions associated with false memory correction. We found that false memories do not overwrite the original trace in all instances, as recovery of the original information was possible. Critically, we determined that recovery of the original information was dependent on activity in regions associated with retrieval, saliency attention, and bottom-up attention during the formation of the false memory, and not on processing at the time of encoding or the second test episode. Project Two. We developed a novel paradigm to test episodic memory for temporal duration. Thirty-five healthy, young adults completed a temporal discrimination task that consisted of a continuous-recognition paradigm in which visual objects were presented one at a time for either 1 or 1.5 seconds. Certain items repeated (Targets and Lures) where Targets were presented for the same duration while the duration of Lures was altered by ±0.5 seconds. Participants were asked to identify whether the stimulus duration changed. Whole-brain high-resolution fMRI data were acquired. Behavioral results indicate that participants were sensitive to both increases and decreases in duration. Further, fMRI analyses revealed that the left entorhinal and perirhinal cortices were differentially involved in encoding and retrieval, respectively, of correct duration representations. These findings support the notion of the entorhinal cortex supporting temporal representations in memory as well as the perirhinal cortex representing the conjunction of item and context.

Degree

PhD

College and Department

Family, Home, and Social Sciences

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2020-04-08

Document Type

Dissertation

Handle

http://hdl.lib.byu.edu/1877/etd11591

Keywords

episodic memory, mnemonic discrimination, false memory, time, MRI

Language

english

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