Alfredo L Sklar1, Brian A Coffman1, Gretchen Haas2, Avniel Ghuman3, Raymond Cho4, Dean F Salisbury5. 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.
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.
Authors: Carsten N Boehler; John K Tsotsos; Mircea A Schoenfeld; Hans-Jochen Heinze; Jens-Max Hopf Journal: J Neurosci Date: 2011-04-06 Impact factor: 6.167
Authors: Steven J Luck; Rebecca L Fuller; Elsie L Braun; Benjamin Robinson; Ann Summerfelt; James M Gold Journal: Schizophr Res Date: 2006-05-19 Impact factor: 4.939