Psychology ETDs


Sephira Ryman

Publication Date

Spring 5-12-2018


Impaired cognitive function results in decreased objective quality of life and community functioning in schizophrenia, resulting in the largest indirect costs from the disease. Disrupted proactive cognitive control, a form of early selection and active goal maintenance, is hypothesized to underlie the broad cognitive deficits observed in patients with schizophrenia. The current study utilized novel electrophysiological (EEG) analytic approach to examine proactive and reactive cognitive control deficits in schizophrenia patients. Behavioral results highlight that patients exhibited a general reduction in reaction time across two multisensory cognitive control tasks, with selective deficits on proactive conditions relative to reactive conditions. The relative difference in performance on proactive conditions predicted functional outcomes. Examination of the electrophysiological mechanisms indicated a general disruption in theta power across tasks, with greater relative deficits on proactive conditions. When accounting for general cognitive ability, these results were less robust. In addition to theta disruption during cognitive control, we also observed decrements in theta power in the sensory cortices whereby patients exhibited a reduced auditory response as well as connectivity between auditory cortex and the frontal midline electrode. Taken together, results highlight that theta activity, which plays a key role in integrating information across the cognitive control network, may reflect a key neurophysiological mechanism of cognitive control that is disrupted in schizophrenia. Given these results, future research should aim to determine if increasing theta activity during proactive cognitive control improves cognitive functioning and functional outcomes in schizophrenia.

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First Committee Member (Chair)

Ronald Yeo, Ph.D.

Second Committee Member

Andrew Mayer, Ph.D.

Third Committee Member

James Cavanagh, Ph.D.

Fourth Committee Member

Robert Toma, Ph.D.




schizophrenia, proactive cognitive control, electroencephalography, theta, functional outcomes, AX-CPT

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