Date of this Version
Davidson, C. A. (2014). Event-Related Potential Correlates of Social and Nonsocial Cognitive Processes Related to Schizotypy. PhD dissertation, University of Nebraska.
Social cognitive, neurocognitive, and social functioning research in serious mental illness (SMI) have recently proliferated. Their synergy requires translational bridges to applied research. This project aims to develop a measurement protocol capable of measuring independent components of social cognitive and neurocognitive brain functioning. These brain processes should each vary systematically with schizotypal traits whose extremes represent core elements of psychotic disorders. The measurement technology must be affordable, efficient, and acceptable for use in clinical settings.
An ERP protocol was developed that incorporates an array of candidate measures. The stimuli consist of emotional (angry and happy), neutral, and scrambled (non-face comparison) faces. Each stimulus was displayed in a sequence of subliminal then supraliminal same-stimulus presentation. The protocol was piloted in an undergraduate sample recruited for a range of schizotypal traits.
Several specific sets of hypotheses were tested. First, feasibility in terms of implementation and attrition was shown to be acceptable with some notable limitations. Second, the ERP protocol was tested for producing reliable conditional waveforms in expected electrode regions. Reliable measurement was achieved for the target components, P1, N170, and P300. Finally, these ERP measures were tested for 1) convergent validity with neuropsychological tests that are used to measure similar brain processes in SMI; 2) reliability as markers of traits that covary with degree of schizotypy and thus may be expected to parallel those in people with SMI; and 3) discriminative validity in measuring independent variance in brain responses to social and non-social stimuli.
Results showed complex conditional effects, including replication, non-replication, and opposite effects compared to hypotheses and previous literature. However, altogether, the results suggest the ERP protocol and assessment battery successfully measured variance in an analogue sample reflecting dimensions related to SMI.
Finally, after having interpreted the relationships of each candidate waveform and comparison independently and with external measures, a brief version of the ERP protocol is proposed that hones in on the stimuli that produce the most powerful measures according to the aforementioned hypotheses.
Adviser: William D. Spaulding