Gevins A S, Cutillo B A, Bressler S L, Morgan N H, White R M, Illes J, Greer D S
EEG Systems Laboratory, San Francisco, CA 94107.
Electroencephalogr Clin Neurophysiol. 1989 Mar-Apr;74(2):147-60. doi: 10.1016/0168-5597(89)90020-8.
Event-related covariance (ERC) patterns were computed from pre-stimulus and feedback intervals of a bimanual, visuomotor judgment task performed by 7 right-handed men. Late contingent negative variation (CNV) ERC patterns that preceded subsequently accurate right- or left-hand responses differed from patterns that preceded subsequently inaccurate responses. Recordings from electrodes placed at left frontal, midline antero-central, and appropriately contralateral central and parietal sites were prominent in ERC patterns of subsequently accurate performances. This suggests that a distributed cortical 'preparatory network,' composed of distinct cognitive, integrative motor, somesthetic, and motor components, is essential for accurate visuomotor performance. ERC patterns related to feedback about accurate and inaccurate responses were similar to each other in the interval immediately after feedback onset, but began to differ in an interval spanning an early P300 peak. The difference became even greater in an interval spanning a late P300 peak. For both early and late P300 peaks, ERC patterns following feedback about inaccurate performance involved more frontal sites than did those following feedback about accurate performance. Together with the stimulus- and response-locked results presented in part I, results of this study on the preparatory and feedback periods suggest that ERCs show salient features of the rapidly shifting, functional cortical networks that are responsible for simple cognitive tasks. ERCs thus provide a new perspective on information processing in the human brain in relation to behavior--a perspective that supplements conventional EEG and ERP procedures.
事件相关协方差（ERC）模式是根据7名右利手男性进行的双手视觉运动判断任务的刺激前和反馈间隔计算得出的。随后准确的右手或左手反应之前的晚期继时性负变（CNV）ERC模式与随后不准确反应之前的模式不同。放置在左额叶、中线前中央以及相应对侧中央和顶叶部位的电极记录在随后准确表现的ERC模式中较为突出。这表明，一个由不同的认知、整合运动、躯体感觉和运动成分组成的分布式皮质“准备网络”对于准确的视觉运动表现至关重要。与准确和不准确反应的反馈相关的ERC模式在反馈开始后的即刻间隔内彼此相似，但在跨越早期P300峰值的间隔内开始出现差异。在跨越晚期P300峰值的间隔内，这种差异变得更大。对于早期和晚期P300峰值，不准确表现反馈后的ERC模式比准确表现反馈后的ERC模式涉及更多的额叶部位。结合第一部分中呈现的刺激锁定和反应锁定结果，本研究在准备期和反馈期的结果表明，ERC显示了负责简单认知任务的快速变化的功能性皮质网络的显著特征。因此，ERC为人类大脑中与行为相关的信息处理提供了一个新的视角——一个补充传统脑电图和ERP程序的视角。
