Townsend J, Westerfield M, Leaver E, Makeig S, Jung T, Pierce K, Courchesne E
Department of Neurosciences 0217, University of California, San Diego, La Jolla 92093-0217, USA.
Brain Res Cogn Brain Res. 2001 Mar;11(1):127-45. doi: 10.1016/s0926-6410(00)00072-0.
Although under some conditions the attention-related late positive event-related potential (ERP) response (LPC) is apparently normal in autism during visual processing, the LPC elicited by visuospatial processing may be compromised. Results from this study provide evidence for abnormalities in autism in two components of the LPC generated during spatial processing. The early frontal distribution of the LPC which may reflect attention orienting was delayed or missing in autistic subjects during conditions in which attention was to peripheral visual fields. The later parietal distribution of the LPC which may be associated with context updating was smaller in amplitude in autistic subjects regardless of attention location. Both abnormalities suggest disruption of function in spatial attention networks in autism. Evidence that the cerebellar abnormalities in autism may underlie these deficits comes from: (1) similar results in ERP responses and spatial attention deficits in patients with cerebellar lesions; (2) brain-behavior correlations in normally functioning individuals associating the size of the posterior cerebellar vermis and the latency of the frontal LPC; and (3) a previously reported complementary correlation between the size of the posterior vermal lobules and spatial orienting speed. Although the scalp-recorded LPC is thought to be cortically generated, it may be modulated by subcortical neural activity. The cerebellum may serve as a modulating influence by affecting the task-related antecedent attentional process. The electrophysiological abnormalities reported here index spatial attention deficits in autism that may reflect cerebellar influence on both frontal and parietal spatial attention function.
尽管在某些条件下，自闭症患者在视觉处理过程中与注意力相关的晚期正性事件相关电位（ERP）反应（LPC）在视觉加工过程中明显正常，但视觉空间加工所引发的LPC可能会受损。本研究结果为自闭症患者在空间加工过程中产生的LPC的两个成分异常提供了证据。在注意力指向外周视野的条件下，自闭症患者中可能反映注意力定向的LPC早期额叶分布延迟或缺失。无论注意力位置如何，自闭症患者中可能与情境更新相关的LPC后期顶叶分布的波幅较小。这两种异常都表明自闭症患者空间注意力网络的功能受到破坏。自闭症患者小脑异常可能是这些缺陷的基础，证据来自：（1）小脑病变患者的ERP反应和空间注意力缺陷的类似结果；（2）正常个体中脑与行为的相关性，将小脑蚓部后部的大小与额叶LPC的潜伏期联系起来；（3）先前报道的蚓部小叶后部大小与空间定向速度之间的互补相关性。尽管头皮记录的LPC被认为是由皮层产生的，但它可能受皮层下神经活动的调节。小脑可能通过影响与任务相关的前期注意力过程起到调节作用。此处报道的电生理异常表明自闭症患者存在空间注意力缺陷，这可能反映了小脑对额叶和顶叶空间注意力功能的影响。
