Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA.
Department of Psychological Sciences, University of Connecticut, Storrs, CT 06269, USA; Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY 10036, USA.
Cell Rep. 2019 Jun 25;27(13):3733-3740.e3. doi: 10.1016/j.celrep.2019.05.094.
The retinas of rabbits and rodents have directionally selective (DS) retinal ganglion cells that convey directional signals through the lateral geniculate nucleus (LGN) of the thalamus to the primary visual cortex (V1). Notably, the function and synaptic impact in V1 of these directional LGN signals are unknown. Here we measured, in awake rabbits, the synaptic impact generated in V1 by individual LGN DS neurons. We show that these neurons make fast and strong connections in layers 4 and 6, with postsynaptic effects that are similar to those made by LGN concentric neurons, the main thalamic drivers of V1. By contrast, the synaptic impact of LGN DS neurons on superficial cortical layers was not detectable. These results suggest that LGN DS neurons activate a cortical column by targeting the main cortical input layers and that the role of DS input to superficial cortical layers is likely to be weak and/or modulatory.
兔子和啮齿动物的视网膜具有方向选择性（DS）的视网膜神经节细胞，这些细胞通过丘脑的外侧膝状体核（LGN）向初级视觉皮层（V1）传递方向信号。值得注意的是，这些定向 LGN 信号在 V1 中的功能和突触影响尚不清楚。在这里，我们在清醒的兔子中测量了单个 LGN DS 神经元在 V1 中产生的突触影响。我们表明，这些神经元在第 4 层和第 6 层形成快速而强大的连接，其突触后效应与 LGN 同心神经元相似，后者是 V1 的主要丘脑驱动神经元。相比之下，LGN DS 神经元对浅层皮质层的突触影响无法检测到。这些结果表明，LGN DS 神经元通过靶向主要的皮质输入层来激活一个皮质柱，并且 DS 输入到浅层皮质层的作用可能较弱和/或具有调节作用。
