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.
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.
Schizophr Res. 2020 Oct;224:126-132. doi: 10.1016/j.schres.2020.09.015. Epub 2020 Oct 21.
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).
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).
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).
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.
在精神分裂症早期阶段，人们对选择性注意的缺陷及其潜在的生物学机制知之甚少。本研究在精神分裂症谱系的首次精神病发作（FESz）中检查了 N2pc，这是一种隐蔽空间注意的神经生理指标及其皮质源。
在弹出和连续搜索任务期间，同时使用脑磁图（MEG）和脑电图（EEG）测量神经生理反应，并将 32 名 FESz 和 32 名匹配的健康对照组（HC）进行比较。从一组后外侧 EEG 电极测量头皮记录的 N2pc 的平均值。源自顶内沟（IPS）和外侧枕叶复合体（LOC）的 N2pc 信号的皮质源分辨 MEG 活动。
EEG N2pc 的组间差异随任务需求而变化。FESz 在弹出时显示 N2pc 幅度降低（p <.01），但在连续搜索时则没有（p =.11）。此外，与任务需求和皮质区域相关的 N2pc 相关 MEG 皮质活动的组间差异。与 HC 相比，FESz 在连续搜索时 IPS 更大（p <.01）。
EEG N2pc 幅度的降低表明在个体首次精神病发作时存在视觉空间注意缺陷，特别是在强调自下而上处理的情况下。用 MEG 检查其皮质源发现，与 HC 相比，FESz 在连续搜索条件下更多地参与顶叶结构。这种模式表明，FESz 采用了效率较低、资源密集度较高的策略来应对注意力的最低要求。对这种受控注意力网络的更大依赖可能会对具有更大复杂性和注意力要求的现实世界功能产生负面影响。
