Savaki H E, Raos V C, Dalezios Y
Department of Basic Sciences, School of Health Sciences, University of Crete, Iraklion, Greece.
Neuroscience. 1997 Feb;76(4):1007-34. doi: 10.1016/s0306-4522(96)00439-3.
The 2-[14C]deoxyglucose method was used to map the metabolic activity in the neocortex of monkeys (Macaca nemestrina) performing a visually guided reaching task with one forelimb. Monkeys received liquid reward for correct, single directional reaching movements, which were required at a rate of about 10 per minute. We estimated the weighted average of local glucose consumption within several neocortical areas, and we reconstructed quantitative, high-resolution, two-dimensional maps of the detailed spatiointensive patterns of activity. Our findings demonstrate the involvement of the striate and prestriate cortices, the inferior intraparietal and superior temporal visual association areas, the frontal eye field and the caudal periprincipal cortex, the primary somatosensory and the related superior intraparietal area, the primary and association auditory cortices, the superior temporal multimodal region, and the premotor, primary, supplementary, and cingulate motor areas. The visual cortex in the superior temporal and the intraparietal sulci, which is concerned with "where", was activated during visually guided reaching. In contrast, the inferior temporal visual association cortex, which is concerned with "what", was not involved in our study. We suggest that the activated direction-selective layer four of V1 and the thick stripes of V2 convey visuomotor information to the activated cortex in the posterior bank and the floor of the superior temporal sulcus, which may encode the constantly updated position of the moving forelimb. In parallel, the activated cortex in the ventral part and the lateral bank of the intraparietal sulcus may encode visuospatial information related to the localization of the visual target in the extrapersonal space. Furthermore, the dorsal part of the medial bank of the intraparietal sulcus may be involved in proprioceptive guidance of movement, based on the parallel metabolic effects shown only contralateral to the moving forelimb within this region and the forelimb representations in the primary somatosensory and motor cortices. Finally, the bilaterally activated network including the inferior postarcuate skeletomotor and prearcuate oculomotor cortical fields and the caudal periprincipal region 46 may participate in sensory and oculomotor to motor transformations, in parallel with the medial and lateral intraparietal cortices with which this network is reciprocally interconnected.
采用2-[¹⁴C]脱氧葡萄糖法绘制了恒河猴（食蟹猴）在执行由视觉引导的单前肢够物任务时新皮层的代谢活动图。猴子每做出一次正确的单向够物动作就能获得液体奖励，动作要求频率约为每分钟10次。我们估算了几个新皮层区域内局部葡萄糖消耗的加权平均值，并重建了活动的详细时空密集模式的定量、高分辨率二维图谱。我们的研究结果表明，纹状皮层和纹前皮层、顶下小叶和颞上视觉联合区、额叶眼区和尾侧中央周围皮层、初级体感皮层和相关的顶上小叶区域、初级听觉皮层和听觉联合皮层、颞上多模态区域以及运动前区、初级运动区、辅助运动区和扣带运动区均参与其中。在视觉引导的够物过程中，颞上沟和顶内沟中与“位置”相关的视觉皮层被激活。相比之下，与“物体识别”相关的颞下视觉联合皮层在我们的研究中未被涉及。我们认为，V1区被激活的方向选择性第4层和V2区的粗条纹将视觉运动信息传递到颞上沟后壁和底部被激活的皮层，该皮层可能编码移动前肢不断更新的位置。同时，顶内沟腹侧部分和外侧壁被激活的皮层可能编码与视觉目标在个人空间外定位相关的视觉空间信息。此外，基于该区域内仅与移动前肢对侧显示出的平行代谢效应以及初级体感皮层和运动皮层中的前肢表征，顶内沟内侧壁的背侧部分可能参与运动的本体感觉引导。最后，包括弓后下骨骼运动和弓前动眼皮层区以及尾侧中央周围46区在内的双侧激活网络可能参与感觉和动眼到运动的转换，这与该网络相互连接的顶内沟内侧和外侧皮层并行。
