Silverstein Steven M, Berten Sarah, Essex Brian, Kovács Ilona, Susmaras Teresa, Little Deborah M
University of Medicine and Dentistry of New Jersey, USA.
J Integr Neurosci. 2009 Jun;8(2):175-202. doi: 10.1142/s0219635209002113.
Behavioral and electrophysiological studies of schizophrenia have consistently demonstrated impairments in the integration of visual features into unified perceptual representations. Specific brain regions involved in this dysfunction, however, remain to be clarified. This study used functional Magnetic Resonance Imaging (fMRI) to examine the relative involvement of visual cortex areas (involved in form perception) and parietal and frontal regions (involved in attention), in the visual integration impairment in schizophrenia. Fourteen patients with schizophrenia and 14 healthy controls were compared on behavioral performance and data acquired via fMRI while completing a contour integration task that had previously been used to identify a visual integration deficit in schizophrenia. The schizophrenia patients demonstrated poorer visual integration than controls. Analyses of peak signal change indicated that while the groups were equivalent in area V1, the schizophrenia group demonstrated reduced signal in areas V2-V4, which are the earliest regions sensitive to global configurations of stimuli. Moreover, whereas the control group demonstrated greater recruitment of prefrontal and parietal areas during perception of integrated forms compared to random stimuli, the schizophrenia group demonstrated greater recruitment of frontal regions during perception of random stimuli. The two groups differed on brain regions involved in form perception even when they were matched on accuracy levels. The visual integration disturbance in schizophrenia involves both deficient basic visual processes (beginning as early as occipital region V2), as well as reduced feedback from visual attention regions that normally serves to amplify relevant visual representations relative to irrelevant information.
对精神分裂症的行为和电生理研究一致表明，在将视觉特征整合为统一的知觉表征方面存在障碍。然而，涉及这种功能障碍的具体脑区仍有待明确。本研究使用功能磁共振成像（fMRI）来检查视觉皮层区域（参与形状感知）以及顶叶和额叶区域（参与注意力）在精神分裂症视觉整合障碍中的相对参与情况。对14名精神分裂症患者和14名健康对照者在完成一项轮廓整合任务时的行为表现和通过fMRI获取的数据进行了比较，该任务此前已被用于识别精神分裂症中的视觉整合缺陷。精神分裂症患者的视觉整合能力比对照组差。峰值信号变化分析表明，虽然两组在V1区域相当，但精神分裂症组在V2 - V4区域的信号减少，而V2 - V4区域是对刺激的整体构型最敏感的最早区域。此外，与随机刺激相比，对照组在整合形状感知过程中前额叶和顶叶区域的激活程度更高，而精神分裂症组在随机刺激感知过程中额叶区域的激活程度更高。即使两组在准确性水平上匹配，它们在参与形状感知的脑区上也存在差异。精神分裂症中的视觉整合障碍既涉及基本视觉过程的缺陷（最早始于枕叶区域V2），也涉及来自视觉注意力区域的反馈减少，而正常情况下这种反馈有助于相对于无关信息放大相关视觉表征。
