Altered Neural and Behavioral Associability-Based Learning in Posttraumatic Stress Disorder

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dc.contributor.authorBrown, Vanessaen
dc.contributor.committeechairChiu, Pearl H.en
dc.contributor.committeememberCasas, Brooksen
dc.contributor.committeememberJones, Russell T.en
dc.contributor.departmentPsychologyen
dc.date.accessioned2017-06-13T19:43:32Zen
dc.date.adate2015-04-24en
dc.date.available2017-06-13T19:43:32Zen
dc.date.issued2015-02-26en
dc.date.rdate2015-06-30en
dc.date.sdate2015-03-06en
dc.description.abstractPosttraumatic stress disorder (PTSD) is accompanied by marked alterations in cognition and behavior, particularly when negative, high-value information is present (Aupperle, Melrose, Stein, & Paulus, 2012; Hayes, Vanelzakker, & Shin, 2012) . However, the underlying processes are unclear; such alterations could result from differences in how this high value information is updated or in its effects on processing future information. To untangle the effects of different aspects of behavior, we used a computational psychiatry approach to disambiguate the roles of increased learning from previously surprising outcomes (i.e. associability; Li, Schiller, Schoenbaum, Phelps, & Daw, 2011) and from large value differences (i.e. prediction error; Montague, 1996; Schultz, Dayan, & Montague, 1997) in PTSD. Combat-deployed military veterans with varying levels of PTSD symptoms completed a learning task while undergoing fMRI; behavioral choices and neural activation were modeled using reinforcement learning. We found that associability-based loss learning at a neural and behavioral level increased with PTSD severity, particularly with hyperarousal symptoms, and that the interaction of PTSD severity and neural markers of associability based learning predicted behavior. In contrast, PTSD severity did not modulate prediction error neural signal or behavioral learning rate. These results suggest that increased associability-based learning underlies neurobehavioral alterations in PTSD.en
dc.description.degreeMaster of Scienceen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-03062015-104820en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-03062015-104820/en
dc.identifier.urihttp://hdl.handle.net/10919/78041en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectfMRIen
dc.subjectreinforcement learningen
dc.subjectassociabilityen
dc.subjectposttraumatic stress disorderen
dc.titleAltered Neural and Behavioral Associability-Based Learning in Posttraumatic Stress Disorderen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplinePsychologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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