Brief monocular deprivation as an assay of short-term visual sensory plasticity in schizophrenia - "the binocular effect".
Brief monocular deprivation as an assay of short-term visual sensory plasticity in schizophrenia - "the binocular effect".
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DOI：
10.3389/fpsyt.2013.00164
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发表时间：
2013-01-01
影响因子：
4.7
通讯作者：
Leavitt, Victoria M
中科院分区：
文献类型：
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作者：
Foxe, John J;Yeap, Sherlyn;Leavitt, Victoria M
背景：在精神分裂症中始终观察到视觉感觉处理缺陷，在处理的最初 50-150 毫秒内视觉诱发电位 (VEP) 幅度明显降低。在未受影响的一级亲属和未接受药物治疗的首发患者中也发现了类似的缺陷，表明这些缺陷是潜在的内表型标志物。精神分裂症还与神经可塑性缺陷有关，涉及谷氨酸能和 GABA 能系统的功能障碍。在这里，我们试图了解这两个领域的交叉点，询问早期视觉处理过程中的短期可塑性是否在精神分裂症中受到特别影响。方法：短暂的单眼剥夺（MD）会导致早期 VEP 幅度相对快速的变化，即短期可塑性。 20 名患者和 20 名非精神病对照者参与了研究。在双眼观看期间记录 VEP，并与短暂的单眼观看期间（即左眼+右眼观看）期间的 VEP 反应总和进行比较。 结果：在单眼条件下，神经典型对照表现出患者未能证明的效果。也就是说，单眼 VEP 的总和幅度明显大于初始感觉处理期间双眼引起的幅度。在患者中，这种“双眼效应”不存在。 局限性：所有患者都接受了药物治疗。理想情况下，这项研究还包括首发未接受药物治疗的患者。 结论：这些结果表明，在精神分裂症患者中，允许健康个体在 MD 背景下产生强大 VEP 的短期补偿机制并未有效激活。这种简单的测定可以为精神障碍的短期可塑性提供有用的生物标志物，并为治疗干预提供目标内表型。
BACKGROUND: Visual sensory processing deficits are consistently observed in schizophrenia, with clear amplitude reduction of the visual evoked potential (VEP) during the initial 50-150ms of processing. Similar deficits are seen in unaffected first-degree relatives and drug-naive first-episode patients, pointing to these deficits as potential endophenotypic markers. Schizophrenia is also associated with deficits in neural plasticity, implicating dysfunction of both glutamatergic and GABAergic systems. Here, we sought to understand the intersection of these two domains, asking whether short-term plasticity during early visual processing is specifically affected in schizophrenia.METHODS: Brief periods of monocular deprivation (MD) induce relatively rapid changes in the amplitude of the early VEP - i.e., short-term plasticity. Twenty patients and 20 non-psychiatric controls participated. VEPs were recorded during binocular viewing, and were compared to the sum of VEP responses during brief monocular viewing periods (i.e., Left-eye+Right-eye viewing).RESULTS: Under monocular conditions, neurotypical controls exhibited an effect that patients failed to demonstrate. That is, the amplitude of the summed monocular VEPs was robustly greater than the amplitude elicited binocularly during the initial sensory processing period. In patients, this "binocular effect" was absent.LIMITATIONS: Patients were all medicated. Ideally, this study would also include first-episode unmedicated patients.CONCLUSION: These results suggest that short-term compensatory mechanisms that allow healthy individuals to generate robust VEPs in the context of MD are not effectively activated in patients with schizophrenia. This simple assay may provide a useful biomarker of short-term plasticity in the psychotic disorders and a target endophenotype for therapeutic interventions.