Magnocellular contributions to impaired motion processing in schizophrenia
Magnocellular contributions to impaired motion processing in schizophrenia
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DOI：
10.1016/j.schres.2005.10.008
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发表时间：
2006-02-15
影响因子：
4.5
通讯作者：
Javitt, DC
中科院分区：
文献类型：
--
作者：
Kim, D;Wylie, G;Javitt, DC
精神分裂症患者在运动处理方面存在损伤，同时在主要涉及大细胞视觉通路的低水平处理方面也存在缺陷。本研究采用神经生理学和行为学相结合的方法，探讨大细胞对精神分裂症患者运动处理受损的潜在影响。与之前精神分裂症的运动研究相比，本研究确定了非相干和相干视觉运动的阈值。在这项研究中，采用阶梯法测量了14名精神分裂症患者和16名年龄匹配的正常对照受试者的速度辨别阈值。通过稳态视觉诱发电位（ssVEP）评估早期视觉处理，通过亮度对比操作使刺激偏向于激活大细胞或小细胞视觉通路。精神分裂症患者对非相干和相干运动的速度辨别能力均较差，组间与任务间无显著交互作用。此外，当在个体确定的非相干运动阈值下测量相干运动表现时，患者的准确率与对照组相似，这也表明在非相干与相干运动辨别方面的缺陷具有相似性。速度辨别能力的损伤与大细胞选择性刺激（而非小细胞选择性刺激）所诱发的ssVEP振幅降低显著相关。本研究表明，精神分裂症患者运动处理的缺陷与大细胞视觉系统的激活降低显著相关。此外，本研究支持并扩展了之前关于精神分裂症患者运动处理受损的报告，并表明自下而上的过程对高阶认知损伤有重要影响。（c）2005爱思唯尔B.V.版权所有。
Patients with schizophrenia show impairments in motion processing, along with deficits in lower level processing primarily involving the magnocellular visual pathway. The present study investigates potential magnocellular contributions to impaired motion processing in schizophrenia using a combined neurophysiological and behavioral approach. As compared to prior motion studies in schizophrenia, thresholds were determined for both incoherent and coherent visual motion. In this study, velocity discrimination thresholds were measured for schizophrenia patients (n = 14) and age-matched normal control subjects (n = 16) using a staircase procedure. Early visual processing was evaluated using steady-state visual evoked potentials (ssVEP), with stimuli biased toward activation of either the magnocellular or parvocellular visual pathways through luminance contrast manipulation. Patients with schizophrenia showed poor velocity discrimination for both incoherent and coherent motion, with no significant group x task interaction. Further, when coherent motion performance was measured at individually determined incoherent motion thresholds, accuracy levels for patients were similar to controls, also indicating similarity of deficit for incoherent vs. coherent motion discrimination. Impairments in velocity discrimination correlated significantly with reduced amplitude of ssVEP elicited by magnocellular - but not parvocellular - selective stimuli. This Study demonstrates that deficits in motion processing in schizophrenia are significantly related to reduced activation of the magnocellular visual system. Further, this study supports and extends prior reports of impaired motion processing in schizophrenia, and indicates significant bottom-up contributions to higher-order cognitive impairments. (c) 2005 Elsevier B.V. All rights reserved.