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Evidence accumulation and the moment of recognition: dissociating perceptual decision processes using fMRI

Ploran, Elisabeth Jeannette (2008) Evidence accumulation and the moment of recognition: dissociating perceptual decision processes using fMRI. Master's Thesis, University of Pittsburgh. (Unpublished)

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Decision making can be conceptualized as the culmination of an integrative process in which evidence supporting different response options accumulates gradually over time. We used functional magnetic resonance imaging (fMRI) to investigate brain activity leading up to and during decisions about perceptual object identity. Pictures were revealed gradually and subjects signaled the time of recognition (TR) with a button press. We examined the timecourse of TR-dependent activity to determine how brain regions tracked the timing of recognition. In several occipital regions, activity increased as stimulus information increased, independently of TR, suggesting a role in lower level sensory processing. In inferior temporal (IT), frontal and parietal regions, a gradual buildup in activity peaking in correspondence with TR suggested that these regions participated in the accumulation of evidence supporting object identity. In medial frontal cortex, anterior insula/frontal operculum, and thalamus, activity remained near baseline until TR, suggesting a relation to the moment of recognition or the decision itself. The findings dissociate neural processes that function in concert during perceptual recognition decisions.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Ploran, Elisabeth Jeannetteeploran@pitt.eduEPLORAN
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairWheeler, Mark Ewheelerm@pitt.eduWHEELERM
Committee MemberReichle, Erikreichle@pitt.eduREICHLE
Committee MemberFiez, Juliefiez@pitt.eduFIEZ
Committee MemberWarren, Tessatessa@pitt.eduTESSA
Date: 4 June 2008
Date Type: Completion
Defense Date: 7 August 2007
Approval Date: 4 June 2008
Submission Date: 22 April 2008
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Psychology
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: decision-making; decisions
Other ID:, etd-04222008-131443
Date Deposited: 10 Nov 2011 19:40
Last Modified: 15 Nov 2016 13:41


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