Klein C, Rockstroh B, Cohen R, Berg P
Department of Psychology, University of Konstanz, Germany.
Schizophr Res. 1996 Aug 23;21(2):97-110. doi: 10.1016/0920-9964(96)00028-x.
A slowly rising cortical potential shift with negative polarity following the imperative stimulus of a forewarned reaction time task, the 'post-imperative negative variation' (PINV), is regularly observed in schizophrenic patients but not in controls. The topography of the PINV suggests that it may originate in frontal cortical regions. We used a task designed to test two putative prefrontal cortical functions: working memory and processing of ambiguity. Nineteen patients with a chronic schizophrenic disorder and 19 control subjects matched for age, sex, and education participated in two experimental sessions. The EEG was recorded from frontal, central, temporal, and parietal leads over both hemispheres using a DC amplifier. PINV amplitudes were generally larger in patients than in controls. If the result of comparing physical features of the two successively presented stimuli (warning and imperative stimulus) was ambiguous rather than clear, an augmentation of the PINV amplitudes was seen in both groups. If this comparison required high rather than low involvement of working memory functions, PINV amplitudes were augmented in schizophrenic patients only. Scalp distribution of the PINV indicated a left-hemisphere fronto-central PINV maximum in patients, and a right-hemisphere predominance in controls, which was larger following ambiguous stimulus comparisons. These results suggest that ambiguity during the comparison of physical features of successively presented stimuli may be a general factor of the PINV in schizophrenic patients and healthy controls. Augmented involvement of working memory functions, presumably subserved by the prefrontal cortex, specifically affected the fronto-centrally predominant PINV in schizophrenic patients. This result is compatible with the hypothesis of prefrontal cortical dysfunctions in schizophrenia.
在有预警的反应时间任务的指令性刺激之后，会出现一种极性为负的皮质电位缓慢上升变化，即“指令后负向变化”（PINV），在精神分裂症患者中经常观察到，而在对照组中则未观察到。PINV的地形图表明它可能起源于额叶皮质区域。我们使用了一项旨在测试两个假定的前额叶皮质功能的任务：工作记忆和模糊性处理。19名患有慢性精神分裂症的患者和19名年龄、性别和教育程度相匹配的对照受试者参加了两个实验环节。使用直流放大器从双侧半球的额叶、中央、颞叶和顶叶导联记录脑电图。患者的PINV振幅通常比对照组大。如果相继呈现的两种刺激（预警刺激和指令性刺激）的物理特征比较结果模糊而非清晰，两组的PINV振幅都会增大。如果这种比较需要较高而非较低的工作记忆功能参与，仅精神分裂症患者的PINV振幅会增大。PINV的头皮分布表明，患者的PINV最大值位于左半球额中央，而对照组中右半球占优势，在模糊刺激比较后更为明显。这些结果表明，相继呈现的刺激的物理特征比较过程中的模糊性可能是精神分裂症患者和健康对照中PINV的一个普遍因素。工作记忆功能的增强参与，可能由前额叶皮质提供支持，特别影响了精神分裂症患者额中央占优势的PINV。这一结果与精神分裂症前额叶皮质功能障碍的假说相符。
