Nagel Matthias, Sprenger Andreas, Hohagen Fritz, Binkofski Ferdinand, Lencer Rebekka
Department of Psychiatry and Psychotherapy, University of Luebeck, Ratzeburger Allee 160, 23538 Luebeck, Germany.
Neuroimage. 2008 Jun;41(2):483-92. doi: 10.1016/j.neuroimage.2008.02.058. Epub 2008 Mar 18.
Smooth pursuit eye movements (SPEM) are used to maintain focus upon moving targets. The generation of SPEM velocity is controlled by retinal information and extraretinal signals. Although there is a wealth of studies investigating retinal and extraretinal SPEM control, the main questions regarding the cortical mechanisms involved in the processing of SPEM to different stimulus velocities are still unresolved. We applied an innovative event-related fMRI-design by presenting target ramps at different velocities (5, 10, 15, 20 degrees/s) with both continuous target presentation and intervals of target blanking. The stimulus parameters were integrated into the statistical model and eye movements were registered to confirm SPEM performance. Our results clearly demonstrate that in humans the oculomotor network (V5, frontal and supplementary eye fields, lateral intraparietal area) is engaged in the processing of retinal and extraretinal SPEM velocity. Within this network neural activity increases with increasing target velocity. During extraretinal SPEM, additional engagement of the dorsolateral prefrontal cortex, angular gyrus, parahippocampal gyrus and superior temporal gyrus occurs. These regions encode cognitive functions such as memory, attention and monitoring. The activation of the inferior parietal cortex seems to be related to the interaction between velocity and blanking thereby underlining its relevance for task switching and sensorimotor transformation.
平稳跟踪眼球运动（SPEM）用于保持对移动目标的聚焦。SPEM速度的产生由视网膜信息和视网膜外信号控制。尽管有大量研究探讨视网膜和视网膜外对SPEM的控制，但关于参与处理不同刺激速度下SPEM的皮层机制的主要问题仍未解决。我们采用了一种创新的事件相关功能磁共振成像设计，通过以不同速度（5、10、15、20度/秒）呈现目标斜坡，同时进行连续目标呈现和目标空白间隔。将刺激参数整合到统计模型中，并记录眼球运动以确认SPEM表现。我们的结果清楚地表明，在人类中，动眼神经网络（V5区、额叶和辅助眼区、顶内沟外侧区）参与了视网膜和视网膜外SPEM速度的处理。在这个网络中，神经活动随着目标速度的增加而增加。在视网膜外SPEM期间，背外侧前额叶皮层、角回、海马旁回和颞上回会有额外的参与。这些区域编码诸如记忆、注意力和监测等认知功能。顶下小叶皮层的激活似乎与速度和空白之间的相互作用有关，从而突出了其与任务转换和感觉运动转换的相关性。
