Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94143, USA.
Cereb Cortex. 2011 Mar;21(3):519-29. doi: 10.1093/cercor/bhq102. Epub 2010 Jul 2.
Little is known about the temporal dynamics of cortical activation during visually guided behavior. We measured changes in brain activity in human posterior parietal cortex (PPC) and premotor cortex (PMC) during saccades and visually guided reaching using magnetoencephalography (MEG) and novel time-frequency reconstructions of MEG (tfMEG) data. Results indicate that early high-gamma activity over the frontal eye fields (FEFs) was present during saccade preparation, and high-gamma activity progressed from the supplementary and FEFs to visual cortex during saccade execution. In contrast, early high-gamma activity over dorsal PMC and late beta activity in primary motor cortex and PPC were unique to reach preparation. During reaching, high-gamma activity progressed from sensorimotor cortex and PMC to parietooccipital cortex. These unique spatial-temporal processing patterns reflect the known connectivity of 2 different sensorimotor networks in macaques. The onset and duration of activity in these areas provides direct evidence for concurrent serial and parallel processing in the human brain during the integration of the sensorimotor inputs necessary for visually guided performance.
目前对于视觉引导行为过程中皮质激活的时间动态变化知之甚少。我们使用脑磁图（MEG）和 MEG（tfMEG）数据的新型时频重建技术，测量了人类顶后皮质（PPC）和运动前皮质（PMC）在扫视和视觉引导伸手过程中的脑活动变化。结果表明，在扫视准备过程中，额眼区（FEF）的早期高γ活动存在，并且在扫视执行过程中，高γ活动从补充运动区和 FEF 区进展到视觉皮层。相比之下，PMC 背侧的早期高γ活动和初级运动皮质和 PPC 的晚期β活动是伸手准备所特有的。在伸手过程中，高γ活动从感觉运动皮质和 PMC 区进展到顶枕叶皮质。这些独特的时空处理模式反映了猕猴中两个不同感觉运动网络的已知连接性。这些区域的活动的起始和持续时间为人类大脑在整合视觉引导表现所需的感觉运动输入时进行并行和串行处理提供了直接证据。
