Nassi Jonathan J, Lyon David C, Callaway Edward M
Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
Neuron. 2006 Apr 20;50(2):319-27. doi: 10.1016/j.neuron.2006.03.019.
Dorsal visual cortical areas are thought to be dominated by input from the magnocellular (M) visual pathway, with little or no parvocellular (P) contribution. These relationships are supported by a close correlation between the functional properties of these areas and the M pathway and by a lack of anatomical evidence for P input. Here we use rabies virus as a retrograde transynaptic tracer to show that the dorsal area MT receives strong input, via a single relay, from both M and P cells of the lateral geniculate nucleus. This surprising P input, likely relayed via layer 6 Meynert cells in primary visual cortex, can provide MT with sensitivity to a more complete range of spatial, temporal, and chromatic cues than the M pathway alone. These observations provide definitive evidence for P pathway input to MT and show that convergence of parallel visual pathways occurs in the dorsal stream.
背侧视觉皮层区域被认为主要由大细胞（M）视觉通路的输入所主导，小细胞（P）的贡献很少或几乎没有。这些区域的功能特性与M通路之间的密切相关性以及缺乏P输入的解剖学证据支持了这些关系。在这里，我们使用狂犬病毒作为逆行跨突触示踪剂，以表明背侧区域MT通过单个中继从外侧膝状体的M细胞和P细胞接收强烈输入。这种令人惊讶的P输入可能通过初级视觉皮层的第6层迈内特细胞中继，可以为MT提供比单独的M通路对更完整的空间、时间和色度线索范围的敏感性。这些观察结果为P通路向MT的输入提供了确凿证据，并表明平行视觉通路在背侧流中发生汇聚。
