Spatiotemporal activity of a cortical network for processing visual motion revealed by MEG and fMRI
Spatiotemporal activity of a cortical network for processing visual motion revealed by MEG and fMRI
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DOI：
10.1152/jn.1999.82.5.2545
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发表时间：
1999-11-01
影响因子：
2.5
通讯作者：
Ilmoniemi, RJ
中科院分区：
文献类型：
--
作者：
Ahlfors, SP;Simpson, GV;Ilmoniemi, RJ
脑磁图和功能磁共振成像显示脑皮层处理视觉运动网络的时空活动。中国生物医学工程学报，32(2):559 - 559,1999。运动方向的突然改变是视觉信息的一个特别显著和相关的特征。广泛的研究已经确定了对视觉运动有反应的皮层区域，并表征了它们对不同运动特征的敏感性，例如方向特异性。然而，人们对方向突然变化的反应知之甚少。来自动物的电生理数据和来自人类的功能成像数据表明，许多大脑区域对运动有反应，可能是一个网络。活动的时间模式允许同一网络以不同的方式处理信息。目前对人类的研究试图确定哪些运动敏感区域参与处理运动方向的变化，并描述大脑区域网络中处理的时间模式。为了做到这一点，我们使用了脑磁图（MEG）和功能磁共振成像（fMRI）。fMRI数据被用作MEG源定位的补充信息。研究发现，视觉运动方向的变化激活了许多区域，每个区域都表现出不同的时间行为。fMRI显示MT+区（猴颞中区，可能还有MT旁边的其他运动敏感区）、颞上沟（pSTS）后端附近的一个区域、V3A和V1/V2有运动相关活动。脑磁图数据显示有其他额叶源。MEG信号发生器的等效偶极子模型显示了MT+的活动。从130毫秒开始，在运动方向逆转后的170毫秒达到峰值，然后再次以类似260毫秒的速度出现。额叶活动开始时间比MT+晚0 ~ 20 ms，高峰时间与180 ms相似。pSTS和FEF+均表现出持续200-400 ms的长时间活动。V3A和V1/V2区的MEG反应相对较小，其峰值潜伏期比MT+的初始峰值更长。这些数据揭示了处理视觉运动方向突然变化的皮层网络活动的特征模式。
Spatiotemporal activity of a cortical network for processing visual motion revealed by MEG and fMRI. J. Neurophysiol. 82: 2545-2555, 1999. A sudden change in the direction of motion is a particularly salient and relevant feature of visual information. Extensive research has identified cortical areas responsive to visual motion and characterized their sensitivity to different features of motion, such as directional specificity. However, relatively little is known about responses to sudden changes in direction. Electrophysiological data from animals and functional imaging data from humans suggest a number of brain areas responsive to motion, presumably working as a network. Temporal patterns of activity allow the same network to process information in different ways. The present study in humans sought to determine which motion-sensitive areas are involved in processing changes in the direction of motion and to characterize the temporal patterns of processing within this network of brain regions. To accomplish this, we used both magnetoencephalography (MEG) and functional magnetic resonance imaging ( fMRI). The fMRI data were used as supplementary information in the localization of MEG sources. The change in the direction of visual motion was found to activate a number of areas, each displaying a different temporal behavior. The fMRI revealed motion-related activity in areas MT+ (the human homologue of monkey middle temporal area and possibly also other motion sensitive areas next to MT), a region near the posterior end of the superior temporal sulcus (pSTS), V3A, and V1/V2. The MEG data suggested additional frontal sources. An equivalent dipole model for the generators of MEG signals indicated activity in MT+. starting at 130 ms and peaking at 170 ms after the reversal of the direction of motion, and then again at similar to 260 ms. Frontal activity began 0-20 ms later than in MT+, and peaked similar to 180 ms. Both pSTS and FEF+ showed long-duration activity continuing over the latency range of 200-400 ms. MEG responses in the region of V3A and V1/V2 were relatively small, and peaked at longer latencies than the initial peak in MT+. These data revealed characteristic patterns of activity in this cortical network for processing sudden changes in the direction of visual motion.