Magnocellular and parvocellular contributions to the responses of neurons in macaque striate cortex
Magnocellular and parvocellular contributions to the responses of neurons in macaque striate cortex
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DOI：
10.1523/jneurosci.14-04-02069.1994
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发表时间：
1994-04
期刊：
影响因子：
--
通讯作者：
T. Nealey;J. Maunsell
中科院分区：
文献类型：
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作者：
T. Nealey;J. Maunsell
灵长类动物视觉系统的解剖学和生理学研究表明，由LGN的大细胞和小细胞亚分裂传递的信号在视觉皮层中保持分离。有人认为，这种分离可能解释了已知的眼外视觉皮层顶叶和颞叶皮层加工流在视觉功能上的差异。为了直接验证这一假设，我们记录了产生颞流的V1（纹状皮层）浅层的视觉反应，同时选择性地灭活LGN的大细胞或微粒细胞细分。细小细胞细分的失活降低了V1浅层的神经元反应，但大细胞阻滞的作用通常同样明显或略强。单个神经元被发现接受来自这两种途径的贡献。我们进一步发现，没有证据表明大细胞的贡献仅限于细胞色素氧化酶团或间团在V1。相反，大细胞信号对整个浅层的反应做出了实质性的贡献。因此，V1内构成时间处理流早期阶段的区域似乎不包含孤立的细胞旁信号。这些结果反对将皮层下的大细胞和小细胞通路直接映射到皮层的顶叶和颞叶处理流上。
Anatomical and physiological studies of the primate visual system have suggested that the signals relayed by the magnocellular and parvocellular subdivisions of the LGN remain segregated in visual cortex. It has been suggested that this segregation may account for the known differences in visual function between the parietal and temporal cortical processing streams in extrastriate visual cortex. To test directly the hypothesis that the temporal stream of processing receives predominantly parvocellular signals, we recorded visual responses from the superficial layers of V1 (striate cortex), which give rise to the temporal stream, while selectively inactivating either the magnocellular or parvocellular subdivisions of the LGN. Inactivation of the parvocellular subdivision reduced neuronal responses in the superficial layers of V1, but the effects of magnocellular blocks were generally as pronounced or slightly stronger. Individual neurons were found to receive contributions from both pathways. We furthermore found no evidence that magnocellular contributions were restricted to either the cytochrome oxidase blobs or interblobs in V1. Instead, magnocellular signals made substantial contributions to responses throughout the superficial layers. Thus, the regions within V1 that constitute the early stages of the temporal processing stream do not appear to contain isolated parvocellular signals. These results argue against a direct mapping of the subcortical magnocellular and parvocellular pathways onto the parietal and temporal streams of processing in cortex.