Moschovakis A K, Gregoriou G G, Ugolini G, Doldan M, Graf W, Guldin W, Hadjidimitrakis K, Savaki H E
Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, and Department of Basic Sciences, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion 71003, Crete, Greece.
J Neurosci. 2004 Jun 23;24(25):5726-40. doi: 10.1523/JNEUROSCI.1223-04.2004.
We used the [14C]-2-deoxyglucose method to study the location and extent of primate frontal lobe areas activated for saccades and fixation and the retrograde transneuronal transfer of rabies virus to determine whether these regions are oligosynaptically connected with extraocular motoneurons. Fixation-related increases of local cerebral glucose utilization (LCGU) values were found around the fundus of the inferior limb of the arcuate sulcus (AS) just ventral to its genu, in the dorsomedial frontal cortex (DMFC), cingulate cortex, and orbitofrontal cortex. Significant increases of LCGU values were found in and around both banks of the AS, DMFC, and caudal principal, cingulate, and orbitofrontal cortices of monkeys executing visually guided saccades. All of these areas are oligosynaptically connected to extraocular motoneurons, as shown by the presence of retrogradely transneuronally labeled cells after injection of rabies virus in the lateral rectus muscle. Our data demonstrate that the arcuate oculomotor cortex occupies a region considerably larger than the classic, electrical stimulation-defined, frontal eye field. Besides a large part of the anterior bank of the AS, it includes the caudal prearcuate convexity and part of the premotor cortex in the posterior bank of the AS. They also demonstrate that the oculomotor DMFC occupies a small area straddling the ridge of the brain medial to the superior ramus of the AS. Our results support the notion that a network of several interconnected frontal lobe regions is activated during rapid, visually guided eye movements and that their output is conveyed in parallel to subcortical structures projecting to extraocular motoneurons.
我们采用[14C]-2-脱氧葡萄糖法来研究灵长类动物额叶中因扫视和注视而激活的区域的位置和范围，并用狂犬病毒的逆行跨神经元转移来确定这些区域与眼外运动神经元是否存在少突触连接。在弓形沟（AS）下肢底部，即其膝部腹侧、背内侧额叶皮质（DMFC）、扣带回皮质和眶额皮质周围，发现了与注视相关的局部脑葡萄糖利用率（LCGU）值升高。在执行视觉引导扫视的猴子的AS两岸及其周围、DMFC以及尾侧主要、扣带回和眶额皮质中，发现LCGU值显著升高。如在外侧直肌注射狂犬病毒后出现逆行跨神经元标记细胞所示，所有这些区域都与眼外运动神经元存在少突触连接。我们的数据表明，弓形动眼皮质所占据的区域比经典的、通过电刺激定义的额叶眼区大得多。除了AS前岸的很大一部分外，它还包括尾侧弓形前凸和AS后岸的部分运动前皮质。数据还表明，动眼DMFC占据了一个小区域，横跨AS上支内侧的脑嵴。我们的研究结果支持这样一种观点，即在快速的视觉引导眼球运动过程中，几个相互连接的额叶区域组成的网络被激活，并且它们的输出并行地传递到投射到眼外运动神经元的皮质下结构。
