VA Desert Pacific Mental Illness Research, Education, and Clinical Center (MIRECC), VA Greater Los Angeles Healthcare System, West Los Angeles VA Healthcare Center, Los Angeles, CA 90073, USA.
Int J Psychophysiol. 2012 Oct;86(1):108-13. doi: 10.1016/j.ijpsycho.2012.06.052. Epub 2012 Jul 4.
When two visual targets are presented in a rapid serial visual presentation (RSVP) paradigm, the ability to identify the second target is reduced when it is presented 200-500ms after the initial target. This phenomenon is referred to as the "attentional blink (AB)." Previous behavioral studies have reported aberrant AB in schizophrenia. The underlying cause, however, of the AB deficit in schizophrenia remains ambiguous. Individuals with schizophrenia consistently demonstrate impairments in early visual processing stages and later attentionally-mediated stages, yet the stage of processing that is contributing to patient-control differences on AB is unknown. The current study attempted to resolve this ambiguity by applying electrophysiological methodology to an RSVP paradigm with 70 clinically stable outpatients with schizophrenia and 63 healthy controls. The task was simplified to reduce task demands, and a suppression ratio was employed to control for possible differences between groups in the ability to identify a single stimulus within a visual stream. Early perceptual processing was assessed using the steady-state visual evoked potential (ssVEP), and attentional processing was assessed using the P300 event-related potential. Relative to the healthy controls, patients showed the expected behavioral AB deficits. These deficits coincided with reduced P300 amplitude: both performance and P300 reductions extended beyond the traditional AB window. Mean ssVEP amplitude did not differ between the groups, and the differences in P300 remained after controlling for ssVEP. These results suggest that the observed AB deficits were due to attentional, not perceptual, processing deficits.
当在快速序列视觉呈现 (RSVP) 范式中呈现两个视觉目标时，如果第二个目标在初始目标之后 200-500ms 呈现，则识别第二个目标的能力会降低。这种现象称为“注意瞬脱 (AB)”。先前的行为研究报告精神分裂症患者的 AB 异常。然而，精神分裂症中 AB 缺陷的根本原因仍然不清楚。精神分裂症患者始终表现出早期视觉处理阶段和后期注意力介导阶段的损伤，但导致患者与对照组在 AB 上差异的处理阶段尚不清楚。本研究试图通过在 70 名临床稳定的精神分裂症门诊患者和 63 名健康对照者中应用电生理方法解决这一模糊性。该任务被简化以降低任务需求，并采用抑制比来控制在视觉流中识别单个刺激的能力在组间可能存在的差异。使用稳态视觉诱发电位 (ssVEP) 评估早期感知处理，使用 P300 事件相关电位评估注意力处理。与健康对照组相比，患者表现出预期的行为 AB 缺陷。这些缺陷与 P300 幅度降低相一致：表现和 P300 降低都超出了传统的 AB 窗口。两组之间的平均 ssVEP 幅度没有差异，并且在控制 ssVEP 后，P300 的差异仍然存在。这些结果表明，观察到的 AB 缺陷是由于注意力而不是感知处理缺陷引起的。
