Colby C L, Gattass R, Olson C R, Gross C G
Department of Psychology, Princeton University, New Jersey 08544.
J Comp Neurol. 1988 Mar 15;269(3):392-413. doi: 10.1002/cne.902690307.
We have examined the origin and topography of cortical projections to area PO, an extrastriate visual area located in the parieto-occipital sulcus of the macaque. Distinguishable retrograde fluorescent tracers were injected into area PO at separate retinotopic loci identified by single-neuron recording. The results indicate that area PO receives retinotopically organized inputs from visual areas V1, V2, V3, V4, and MT. In each of these areas the projection to PO arises from the representation of the periphery of the visual field. This finding is consistent with neurophysiological data indicating that the representation of the periphery is emphasized in PO. Additional projections arise from area MST, the frontal eye fields, and several divisions of parietal cortex, including four zones within the intraparietal sulcus and a region on the medial dorsal surface of the hemisphere (MDP). On the basis of the laminar distribution of labeled cells we conclude that area PO receives an ascending input from V1, V2, and V3 and receives descending or lateral inputs from all other areas. Thus, area PO is at approximately the same level in the hierarchy of visual areas as areas V4 and MT. Area PO is connected both directly and indirectly, via MT and MST, to parietal cortex. Within parietal cortex, area PO is linked to particular regions of the intraparietal sulcus including VIP and LIP and two newly recognized zones termed here MIP and PIP. The wealth of connections with parietal cortex suggests that area PO provides a relatively direct route over which information concerning the visual field periphery can be transmitted from striate and prestriate cortex to parietal cortex. In contrast, area PO has few links with areas projecting to inferior temporal cortex. The pattern of connections revealed in this study is consistent with the view that area PO is primarily involved in visuospatial functioning.
我们研究了向猕猴顶枕沟中一个纹外视觉区域PO区的皮质投射的起源和定位。通过单神经元记录在不同的视网膜拓扑位点将可区分的逆行荧光示踪剂注入PO区。结果表明，PO区从视觉区域V1、V2、V3、V4和MT接收视网膜拓扑组织的输入。在这些区域中的每一个，向PO区的投射都来自视野周边的表征。这一发现与神经生理学数据一致，该数据表明PO区强调周边的表征。额外的投射来自MST区、额叶眼区以及顶叶皮质的几个分区，包括顶内沟内的四个区域和半球内侧背表面的一个区域（MDP）。根据标记细胞的层状分布，我们得出结论，PO区从V1、V2和V3接收上行输入，并从所有其他区域接收下行或侧向输入。因此，PO区在视觉区域层次结构中与V4区和MT区处于大致相同的水平。PO区通过MT区和MST区直接和间接地与顶叶皮质相连。在顶叶皮质内，PO区与顶内沟的特定区域相连，包括VIP区和LIP区以及这里称为MIP区和PIP区的两个新识别区域。与顶叶皮质丰富的连接表明，PO区提供了一条相对直接的路径，通过该路径，有关视野周边的信息可以从纹状和纹前皮质传递到顶叶皮质。相比之下，PO区与投射到颞下皮质的区域几乎没有联系。本研究中揭示的连接模式与PO区主要参与视觉空间功能的观点一致。
