Differential Architecture of Multisynaptic Geniculo-Cortical Pathways to V4 and MT
Differential Architecture of Multisynaptic Geniculo-Cortical Pathways to V4 and MT
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DOI：
10.1093/cercor/bhr078
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发表时间：
2011-12-01
期刊：
影响因子：
3.7
通讯作者：
Takada, Masahiko
中科院分区：
文献类型：
--
作者：
Ninomiya, Taihei;Sawamura, Hiromasa;Takada, Masahiko
在灵长类动物脑中，被称为背侧流和腹侧流的平行视觉通路主要通过外侧膝状体核的大细胞（M）层和小细胞（P）层接收视网膜输入。来自这些层的输入在V1的层4C的不同部分内终止（视觉区域1）。由于V1和更高视觉区域中M和P源性神经连接的复杂性，M和P输入对背侧和腹侧流的贡献仍然不清楚。采用狂犬病毒的逆行跨突触转运，我们分析了自下而上的途径腹侧流区V4（视觉区4）和背侧流区MT（中颞区）的架构。我们发现，V4通过V1的2/3层从4C层“三突触地”接收M和P输入，而MT通过V1的4 B层从4C层“双突触地”接收M主导输入。V4还接收来自V2的背侧流部分（视觉区域2）的双突触输入（即，细胞色素氧化酶染色的粗条纹）。此外，M和P的输入达到V4三突触和MT双突触通过“捷径”的途径，绕过层4C的V1。V4和MT的多突触膝状皮质通路的差异模式意味着背侧流和腹侧流的信息处理模式不同。
Parallel visual pathways in the primate brain known as the dorsal and ventral streams receive retinal inputs mainly through the magnocellular (M) and parvocellular (P) layers of the lateral geniculate nucleus. Inputs from these layers terminate within distinct parts of layer 4C of V1 (visual area 1). Due to the complexity of M- and P-derived neural connectivity in V1 and higher visual areas, the contributions of M and P inputs to the dorsal and ventral streams remain unclear. Employing retrograde transsynaptic transport of rabies virus, we analyzed the architecture of bottom-up pathways toward ventral stream area V4 (visual area 4) and dorsal stream area MT (middle temporal area). We found that V4 receives both M and P inputs "trisynaptically" from layer 4C via layer 2/3 of V1, whereas MT receives M-dominant input "disynaptically" from layer 4C via layer 4B of V1. V4 also receives disynaptic input from the dorsal stream portion of V2 (visual area 2) (i.e., cytochrome oxidase-stained thick stripes). Moreover, both M and P inputs reach V4 trisynaptically and MT disynaptically through "short-cut" pathways that bypass layer 4C of V1. The differential patterns of multisynaptic geniculo-cortical pathways to V4 and MT imply distinct modes of information processing in the dorsal and ventral streams.