ARC Centre of Excellence in Vision Science, The University of Sydney Eye Hospital Campus, Sydney, New South Wales 2001, Australia.
J Neurosci. 2013 Apr 17;33(16):6864-76. doi: 10.1523/JNEUROSCI.5208-12.2013.
Most neurons in primary visual cortex (V1) exhibit high selectivity for the orientation of visual stimuli. In contrast, neurons in the main thalamic input to V1, the lateral geniculate nucleus (LGN), are considered to be only weakly orientation selective. Here we characterize a sparse population of cells in marmoset LGN that show orientation and spatial frequency selectivity as great as that of cells in V1. The recording position in LGN and histological reconstruction of these cells shows that they are part of the koniocellular (K) pathways. Accordingly we have named them K-o ("koniocellular-orientation") cells. Most K-o cells prefer vertically oriented gratings; their contrast sensitivity and TF tuning are similar to those of parvocellular cells, and they receive negligible functional input from short wavelength-sensitive ("blue") cone photoreceptors. Four K-o cells tested displayed binocular responses. Our results provide further evidence that in primates as in nonprimate mammals the cortical input streams include a diversity of visual representations. The presence of K-o cells increases functional homologies between K pathways in primates and "sluggish/W" pathways in nonprimate visual systems.
初级视皮层（V1）中的大多数神经元对视觉刺激的方向表现出高度选择性。相比之下，V1 的主要丘脑输入核——外侧膝状体核（LGN）中的神经元被认为只有较弱的方向选择性。在这里，我们描述了狨猴 LGN 中一个稀疏的细胞群体，它们表现出与 V1 细胞相当的方向和空间频率选择性。这些细胞的 LGN 记录位置和组织学重建表明，它们是 koniocellular（K）通路的一部分。因此，我们将它们命名为 K-o（“koniocellular-orientation”）细胞。大多数 K-o 细胞更喜欢垂直定向的光栅；它们的对比度敏感度和 TF 调谐与小细胞相似，并且从短波长敏感（“蓝色”）视锥感受器接收微不足道的功能输入。四个 K-o 细胞测试显示出双眼反应。我们的结果进一步证明，在灵长类动物和非灵长类哺乳动物中，皮质输入流包括多种视觉表现形式。K-o 细胞的存在增加了灵长类动物的 K 通路与非灵长类视觉系统中的“迟钝/W”通路之间的功能同源性。
