Hedonic response is preserved in schizophrenia. However, it is unclear whether this is also true in individuals meeting criteria for “prodromal” psychosis, who are considered to be at symptomatic high risk for developing the disorder. In this study, we examined neurophysiological and self-reported response to emotional stimuli in UHR (n = 23) and healthy control (CN: n = 30) participants who passively viewed pleasant, unpleasant, and neutral images for 500 ms while the electroencephalogram was recorded and then provided self-reports of valence and arousal to the stimuli. The Late Positive Potential (LPP) event related potential (ERP) component was used as a neurophysiological marker of emotional reactivity. Results indicated that CN participants had higher LPP amplitude for pleasant and unpleasant compared to neutral stimuli; however, UHR youth displayed no differences in LPP amplitude among pleasant, unpleasant, and neutral stimuli. Self-report data mirrored neurophysiological data, as UHR youth had lower reports of positive emotion to pleasant stimuli and negative emotion to unpleasant stimuli compared to CN participants. Furthermore, the presence of a mood disorder diagnosis predicted reduced neurophysiological emotional reactivity in UHR youth.Findings suggest that youth at UHR for psychosis display diminished subjective and neurophysiological reactivity to emotional stimuli, and that symptoms of depression may result in diminished emotional reactivity.

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One of the proposed neural mechanisms involved in working memory is coupling between the theta phase and gamma amplitude. For example, evidence from intracranial recordings shows that coupling between hippocampal theta and cortical gamma oscillations increases selectively during working memory tasks. Theta-gamma phase-amplitude coupling can also be measured non-invasively through scalp EEG; however, EEG can only assess coupling within cortical areas, and it is not yet clear if this cortical-only coupling is truly memory-specific, or a more general phenomenon. We tested this directly by measuring cortical coupling during three different conditions: a working memory task, an attention task, and a passive perception condition. We find similar levels of theta-gamma coupling in all three conditions, suggesting that cortical theta-gamma phase-amplitude coupling is not a memory-specific signal, but instead reflects some other attentional or perceptual processes. Implications for understanding the brain dynamics of visual working memory are discussed.

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