Doniger Glen M, Foxe John J, Murray Micah M, Higgins Beth A, Javitt Daniel C
Cognitive Neurophysiology Laboratory, Cognitive Neuroscience and Schizophrenia Program, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
Arch Gen Psychiatry. 2002 Nov;59(11):1011-20. doi: 10.1001/archpsyc.59.11.1011.
Schizophrenia is associated with well-documented deficits in high-order cognitive processes such as attention and executive functioning. The integrity of sensory-level processing, however, has been evaluated only to a limited degree. Our study evaluated the ability of patients with schizophrenia to recognize complete objects based on fragmentary information, a process termed perceptual closure. Perceptual closure processes are indexed by closure negativity (N(cl)), a recently defined event-related potential (ERP) component that is generated within the visual association cortex. This study assessed the neural integrity of perceptual closure processes in schizophrenia by examining N(cl) generation. Generation of the preceding positive (P1) and negative (N1) ERP components was also examined.
We evaluated 16 patients with chronic schizophrenia and 16 healthy comparison subjects. Successively less fragmented images were presented during high-density ERP recording, which permitted the monitoring of brain activity during perceptual closure processes prior to object recognition. Analyses were performed at parieto-occipital and occipitotemporal sites consistent with dorsal and ventral stream generators of P1, N1, and N(cl).
Patients with schizophrenia showed significant impairment in the ability to recognize fragmented objects, along with impaired generation of N(cl). The amplitude of visual P1 was significantly reduced, particularly over dorsal stream sites. In contrast, the generation of visual N1 was intact.
Patients with schizophrenia are profoundly impaired in perceptual closure as indicated by both impaired performance and impaired N(cl) generation. The selective impairment in dorsal stream P1 is consistent with prior reports of impaired magnocellular processing in schizophrenia. By contrast, intact ventral N1 generation suggests that the initial stages of ventral stream processing are relatively preserved and that impaired magnocellular dorsal stream functioning in schizophrenia may lead to secondary dysregulation of ventral stream object recognition processing.
精神分裂症与注意力和执行功能等高阶认知过程中记录详实的缺陷有关。然而，感觉水平加工的完整性仅在有限程度上得到评估。我们的研究评估了精神分裂症患者基于片段信息识别完整物体的能力，这一过程称为知觉闭合。知觉闭合过程由闭合负波（N(cl)）索引，N(cl)是最近定义的一种事件相关电位（ERP）成分，在视觉联合皮层中产生。本研究通过检查N(cl)的产生来评估精神分裂症中知觉闭合过程的神经完整性。还检查了先前的正性（P1）和负性（N1）ERP成分的产生。
我们评估了16例慢性精神分裂症患者和16名健康对照者。在高密度ERP记录期间，依次呈现碎片化程度越来越低的图像，这使得在物体识别之前的知觉闭合过程中能够监测大脑活动。在与P1、N1和N(cl)的背侧和腹侧流发生器一致的顶枕和枕颞部位进行分析。
精神分裂症患者在识别碎片化物体的能力上表现出显著受损，同时N(cl)的产生也受损。视觉P1的波幅显著降低，尤其是在背侧流部位。相比之下，视觉N1的产生是完整的。
精神分裂症患者在知觉闭合方面存在严重受损，表现为表现受损和N(cl)产生受损。背侧流P1的选择性受损与先前关于精神分裂症中巨细胞加工受损的报道一致。相比之下，腹侧N1产生完整表明腹侧流加工的初始阶段相对保留，并且精神分裂症中巨细胞背侧流功能受损可能导致腹侧流物体识别加工的继发性失调。
