Inefficient visual search strategies in the first-episode schizophrenia spectrum

Alfredo L Sklar; Brian A Coffman; Gretchen Haas; Avniel Ghuman; Raymond Cho; Dean F Salisbury

doi:10.1016/j.schres.2020.09.015

Inefficient visual search strategies in the first-episode schizophrenia spectrum

Schizophr Res. 2020 Oct:224:126-132. doi: 10.1016/j.schres.2020.09.015. Epub 2020 Oct 21.

Authors

Alfredo L Sklar¹, Brian A Coffman¹, Gretchen Haas², Avniel Ghuman³, Raymond Cho⁴, Dean F Salisbury⁵

Affiliations

¹ Clinical Neurophysiology Research Laboratory, UPMC Western Psychiatric Hospital, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; UPMC Western Psychiatric Hospital, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
² UPMC Western Psychiatric Hospital, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA; VA Pittsburgh Healthcare System and VISN 4 MIRECC, U.S. Dept of Veterans Affairs, Pittsburgh, PA, USA.
³ Laboratory of Cognitive Neurodynamics, Department of Neurosurgery, Presbyterian Hospital, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
⁴ Department of Psychiatry, Baylor College of Medicine and Michael E. DeBakey VA Medical Center, Houston, TX, USA.
⁵ Clinical Neurophysiology Research Laboratory, UPMC Western Psychiatric Hospital, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; UPMC Western Psychiatric Hospital, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. Electronic address: salisburyd@upmc.edu.

Abstract

Background: Knowledge is lacking regarding deficits in selective attention and their underlying biological mechanisms during early stages of schizophrenia. The present study examined the N2pc, a neurophysiological index of covert spatial attention, and its cortical sources at first psychotic episode in the schizophrenia spectrum (FESz).

Methods: Neurophysiological responses measured simultaneously with magnetoencephalography (MEG) and electroencephalography (EEG) during pop-out and serial search tasks were compared between 32 FESz and 32 matched healthy controls (HC). Mean scalp-recorded N2pc was measured from a cluster of posterior-lateral EEG electrodes. Cortical source-resolved MEG activity contributing to the N2pc signal was derived for the intraparietal sulcus (IPS) and lateral occipital complex (LOC).

Results: Group differences in EEG N2pc varied by task demand. FESz exhibited reduced N2pc amplitude during pop-out (p < .01), but not serial search (p = .11). Furthermore, group differences in N2pc-related MEG cortical activity varied by task demand and cortical region. Compared to HC, FESz exhibited greater IPS during serial search (p < .01).

Discussion: Reductions in EEG N2pc amplitude indicate an impairment of visuo-spatial attention evident at an individual's first psychotic episode, specifically during conditions emphasizing bottom-up processing. Examination of its cortical sources with MEG revealed that, compared to HC, FESz engaged parietal structures to a greater extent during the serial search condition. This pattern suggests a less efficient, more resource intensive strategy employed by FESz in response to a minimal demand on attention. The greater reliance on this controlled attentional network may negatively impact real-world functions with much greater complexity and attentional demands.

Keywords: First-episode; Magnetoencephalography; N2pc; Schizophrenia spectrum; Selective attention; Visual search.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Attention
Electroencephalography
Humans
Magnetoencephalography
Psychotic Disorders*
Schizophrenia*

Abstract

Publication types

MeSH terms

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