Department of Neurology, Otto-von-Guericke-University, Magdeburg, Germany.
PLoS One. 2010 Jan 13;5(1):e8691. doi: 10.1371/journal.pone.0008691.
The superior colliculus (SC) has been shown to play a crucial role in the initiation and coordination of eye- and head-movements. The knowledge about the function of this structure is mainly based on single-unit recordings in animals with relatively few neuroimaging studies investigating eye-movement related brain activity in humans.
METHODOLOGY/PRINCIPAL FINDINGS: The present study employed high-field (7 Tesla) functional magnetic resonance imaging (fMRI) to investigate SC responses during endogenously cued saccades in humans. In response to centrally presented instructional cues, subjects either performed saccades away from (centrifugal) or towards (centripetal) the center of straight gaze or maintained fixation at the center position. Compared to central fixation, the execution of saccades elicited hemodynamic activity within a network of cortical and subcortical areas that included the SC, lateral geniculate nucleus (LGN), occipital cortex, striatum, and the pulvinar.
CONCLUSIONS/SIGNIFICANCE: Activity in the SC was enhanced contralateral to the direction of the saccade (i.e., greater activity in the right as compared to left SC during leftward saccades and vice versa) during both centrifugal and centripetal saccades, thereby demonstrating that the contralateral predominance for saccade execution that has been shown to exist in animals is also present in the human SC. In addition, centrifugal saccades elicited greater activity in the SC than did centripetal saccades, while also being accompanied by an enhanced deactivation within the prefrontal default-mode network. This pattern of brain activity might reflect the reduced processing effort required to move the eyes toward as compared to away from the center of straight gaze, a position that might serve as a spatial baseline in which the retinotopic and craniotopic reference frames are aligned.
上丘（SC）在眼动和头动的启动和协调中起着至关重要的作用。关于该结构的功能的知识主要基于动物的单细胞记录，而涉及人类与眼动相关的大脑活动的神经影像学研究相对较少。
方法/主要发现：本研究采用高场（7 特斯拉）功能磁共振成像（fMRI）技术，研究人类自主提示扫视时 SC 的反应。在中央呈现指导线索的情况下，被试要么将眼睛扫视离开（离心）或朝向（向心）正前方注视中心，要么保持注视中心位置。与中心注视相比，执行扫视会引起皮质和皮质下区域网络的血液动力学活动，包括 SC、外侧膝状体核（LGN）、枕叶皮层、纹状体和丘脑枕。
结论/意义：在离心和向心扫视时，SC 中的活动在与扫视方向相反的一侧增强（即，左向扫视时右 SC 的活动比左 SC 大，反之亦然），这表明动物中存在的扫视执行的对侧优势也存在于人类的 SC 中。此外，离心扫视比向心扫视在 SC 中引起更大的活动，同时在前额默认模式网络中也伴随着去激活增强。这种大脑活动模式可能反映了将眼睛移向注视中心比移离注视中心所需的处理工作量减少，注视中心可能作为一个空间基准，在此基准中，视网膜和颅顶参考系是对齐的。
