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Emitted P3a and P3b in chronic schizophrenia and in first-episode schizophrenia

McCathern, Alexis (2017) Emitted P3a and P3b in chronic schizophrenia and in first-episode schizophrenia. Undergraduate Thesis, University of Pittsburgh. (Unpublished)

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Neurophysiological biomarkers may be useful for identifying the presence of schizophrenia and the schizophrenia prodrome among at-risk individuals prior to the emergence of psychosis. This study examined the emitted P3 to absent stimuli on a tone counting task in patients with chronic schizophrenia and newly-diagnosed patients. The P3 is biphasic, with the earlier peak (P3a) reflecting automatic orienting and the later peak (P3b) reflecting cognitive processing. Twenty-four individuals with long-term schizophrenia (minimum 5 years diagnosis; SZ) were compared to 24 matched controls (HCSZ), and 23 individuals within 6 months of their first psychotic episode (FE) were compared to 22 matched controls (HCFE). Participants were presented with standard sets of four identical tones (1 kHz, 50 ms, 330 ms SOA, 750 ms ITI). For one in seven sets, the fourth tone was missing. Participants simply counted the number of tones within each set, with no instruction to detect missing tones. The P3a emitted by missing tones was significantly reduced in SZ compared to HCSZ (p=.044). The P3b emitted by missing tones was significantly reduced in both SZ and FE compared to their matched control groups (p=.049 and p=.036 respectively). SZ and FE showed impaired generation of the emitted P3b during selective attention to stimuli. The emitted P3b may be useful to understand cognitive neuropathophysiology early in psychosis, and shows promise as a biomarker to help detect the true schizophrenia prodrome among clinical high risk individuals prior to disease onset.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
McCathern, Alexisagm42@pitt.eduagm42
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairSalisbury,
Committee MemberFoxe,
Committee MemberPogue-Geile,
Committee MemberSteinhauer,
Date: 24 April 2017
Date Type: Publication
Defense Date: 3 April 2017
Approval Date: 24 April 2017
Submission Date: 13 April 2017
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 37
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Neuroscience
Dietrich School of Arts and Sciences > Psychology
David C. Frederick Honors College
Degree: BPhil - Bachelor of Philosophy
Thesis Type: Undergraduate Thesis
Refereed: Yes
Uncontrolled Keywords: schizophrenia, first-episode, EEG, emitted P300, event-related potential, orienting attention
Date Deposited: 24 Apr 2017 19:21
Last Modified: 25 Apr 2017 05:15


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