Department of Neurology, University of Lübeck, Germany.
Clin Neurophysiol. 2013 May;124(5):881-92. doi: 10.1016/j.clinph.2012.11.003. Epub 2013 Jan 26.
Disturbances of information selection under high processing load might be a key feature predisposing to psychotic disorders. The N2pc component of the ERP is a specific measure of selective attention. It is unclear whether N2pc is altered under increased demands in patients with psychosis.
Patients with schizophrenia, with bipolar disorder (n = 20 each), and age-matched healthy controls (n = 21) had to identify two targets ("T1" and "T2") in two different simultaneous rapidly presented series of letters. We assessed the target-evoked N2pc and P3 components and the visually evoked potentials (VEPs) evoked by the rapid stream.
T1 and T2 identification rates did not substantially differ between groups. However, T1- and T2-evoked N2pc components were reduced in both patient groups. VEPs were enlarged in response to the first stimulus of the fast series in healthy participants but not in patients. T2-evoked P3 was reduced in patients with schizophrenia only.
Under high attentional load, neurophysiological mechanisms underlying visual selection are compromised in patients with psychosis. The lacking VEP increase to the first stimulus probably indicates deficient arousal.
These deficiencies of attentional selection and arousal might enhance liability to psychotic symptoms under stressful conditions.
在高处理负荷下信息选择的紊乱可能是导致精神病的一个关键特征。ERP 的 N2pc 成分是选择性注意的特定测量指标。目前尚不清楚在精神病患者的需求增加时 N2pc 是否会发生变化。
精神分裂症患者（n = 20）、双相情感障碍患者（n = 20）和年龄匹配的健康对照组（n = 21）必须在两个不同的快速呈现字母系列中识别两个目标（“T1”和“T2”）。我们评估了目标诱发的 N2pc 和 P3 成分以及快速流诱发的视觉诱发电位（VEPs）。
T1 和 T2 的识别率在各组之间没有明显差异。然而，两组患者的 T1 和 T2 诱发的 N2pc 成分均减少。健康参与者对快速系列的第一个刺激会引起 VEPs 增大，但患者不会。只有精神分裂症患者的 T2 诱发的 P3 减少。
在高注意力负荷下，精神病患者的视觉选择的神经生理机制受损。对第一个刺激缺乏 VEP 增加可能表明唤醒不足。
这些注意力选择和唤醒的缺陷可能会在应激条件下增强出现精神病症状的易感性。
