Department of Psychiatry, University of California San Diego La Jolla, CA, USA.
Front Psychol. 2013 Aug 20;4:535. doi: 10.3389/fpsyg.2013.00535. eCollection 2013.
Individuals with schizophrenia spectrum diagnoses have deficient visual information processing as assessed by a variety of paradigms including visual backward masking, motion perception and visual contrast sensitivity (VCS). In the present study, the VCS paradigm was used to investigate potential differences in magnocellular (M) vs. parvocellular (P) channel function that might account for the observed information processing deficits of schizophrenia spectrum patients. Specifically, VCS for near threshold luminance (black/white) stimuli is known to be governed primarily by the M channel, while VCS for near threshold chromatic (red/green) stimuli is governed by the P channel.
VCS for luminance and chromatic stimuli (counterphase-reversing sinusoidal gratings, 1.22 c/degree, 8.3 Hz) was assessed in 53 patients with schizophrenia (including 5 off antipsychotic medication), 22 individuals diagnosed with schizotypal personality disorder and 53 healthy comparison subjects.
Schizophrenia spectrum groups demonstrated reduced VCS in both conditions relative to normals, and there was no significant group by condition interaction effect. Post-hoc analyses suggest that it was the patients with schizophrenia on antipsychotic medication as well as SPD participants who accounted for the deficits in the luminance condition.
These results demonstrate visual information processing deficits in schizophrenia spectrum populations but do not support the notion of selective abnormalities in the function of subcortical channels as suggested by previous studies. Further work is needed in a longitudinal design to further assess VCS as a vulnerability marker for psychosis as well as the effect of antipsychotic agents on performance in schizophrenia spectrum populations.
通过各种范式（包括视觉后向掩蔽、运动知觉和视觉对比敏感度 (VCS)）评估，患有精神分裂谱系诊断的个体存在视觉信息处理缺陷。在本研究中，使用 VCS 范式研究了可能导致精神分裂谱系患者观察到的信息处理缺陷的大细胞 (M) 与小细胞 (P) 通道功能的差异。具体来说，近阈值亮度（黑白）刺激的 VCS 主要由 M 通道控制，而近阈值色度（红/绿）刺激的 VCS 由 P 通道控制。
评估了 53 名精神分裂症患者（包括 5 名停用抗精神病药物的患者）、22 名诊断为精神分裂型人格障碍的个体和 53 名健康对照者的亮度和色度刺激 VCS（反相正弦光栅，1.22 c/度，8.3 Hz）。
精神分裂谱系组在两种条件下的 VCS 均低于正常组，且组间条件无显著交互作用。事后分析表明，正是服用抗精神病药物的精神分裂症患者和 SPD 参与者导致了亮度条件下的缺陷。
这些结果表明精神分裂谱系人群存在视觉信息处理缺陷，但不支持先前研究中提出的皮质下通道功能选择性异常的观点。需要在纵向设计中进一步研究 VCS 作为精神病易感性标志物以及抗精神病药物对精神分裂谱系人群表现的影响。
