Working memory deficit in high schizotypy: ERP but no power differences

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Jenna N. Pablo¹ (jpablo@nevada.unr.edu), Wendy A. Torrens¹, Jorja Shires¹, Sarah M. Haigh¹, Marian E. Berryhill¹; ¹University of Nevada, Reno

Individuals with schizophrenia spectrum disorders exhibit working memory (WM) impairments. Here, we tested WM performance in subclinical schizotypy to examine the effects of symptom load on cognition without the onset of psychosis and to identify a biomarker of WM deficits. We recorded EEG while 21 controls and 14 undergraduates high in schizotypy completed an auditory 2-back WM task. Participants listened to a sequence of digits (0-9) presented via earphones and reported whether stimuli matched or mismatched the digit presented two prior. The behavioral data revealed that WM accuracy was impaired in the high schizotypy group (M=83%) compared to controls (M=91%; t(33)=2.15, p=.04). To understand the underlying mechanism, we conducted time-frequency analyses to probe altered power (1-30 Hz) across the delay period. The cluster-based permutation test indicates no differences between the groups (p>.05). Next, we evaluated amplitude differences (averaged over a frontal electrode cluster) in the event-related potentials. Results show significant group-level differences when applying a sliding window (20 ms bin width, non-overlapping). Past literature shows the P300, a neural signature reflective of WM processes, is reduced in schizophrenia. However, our results show no group differences in the P300 (p=.76, Mann-Whitney test). These results suggest there may be alternative biomarkers of WM deficits, besides the canonical P300. Although WM performance may be associated with symptom load, a robust neural mechanism explaining this deficit remains elusive. Further research is needed to identify the neural mechanism of WM impairment in high schizotypy.

Topic Area: EXECUTIVE PROCESSES: Working memory