Feedback connections to ferret striate cortex: Direct evidence for visuotopic convergence of feedback inputs
Feedback connections to ferret striate cortex: Direct evidence for visuotopic convergence of feedback inputs
复制标题
DOI：
10.1002/cne.20570
复制
发表时间：
2005-07-04
影响因子：
2.5
通讯作者：
Levitt, JB
中科院分区：
文献类型：
--
作者：
Cantone, G;Xiao, J;Levitt, JB
真核反馈连接是皮层结构的一个基本方面，但它们的组织和功能相关性的许多方面仍然知之甚少。先前的研究已经调查了从纹外皮层到猕猴17区的反馈投射的地形。我们已将这种分析扩展到雪貂。我们将霍乱毒素B（CT B）限制性注射到雪貂17区，并绘制了逆行标记细胞在纹外皮质的分布。除了在17区广泛的标签传播，我们发现密集的细胞标签在18，19和21区和上外侧颞叶皮层和稀疏的连接从侧颞叶和后顶叶皮层。我们对纹外视皮层的放大因子进行了广泛的生理评估，并使用这些措施将标记皮层的毫米范围转换为视野范围。我们还直接测量了视敏度的感受野在含有标记细胞的区域中的情况下，我们在同一动物中进行了CTb注射和生理记录;然后我们比较了标记区域的聚合感受野（ARF）在每个纹外区与注射部位。在区域18、19和21中，含有标记神经元的区域中的细胞的感受野与注射部位处的细胞的感受野重叠，但在视觉空间中比注射部位的ARF跨越更大的距离。反馈连接的广泛视觉范围与它们有助于经典感受野之外的刺激的反应调制的建议是一致的。(c)2005 Wiley-Liss，Inc.
Interareal feedback connections are a fundamental aspect of cortical architecture, yet many aspects of their organization and functional relevance remain poorly understood. Previous studies have investigated the topography of feedback projections from extrastriate cortex to macaque area 17. We have extended this analysis to the ferret. We made restricted injections of cholera toxin B (CTb) into ferret area 17 and mapped the distribution of retrogradely labeled cells in extrastriate cortex. In addition to extensive label spreading within area 17, we found dense cell label in areas 18, 19, and 21 and the suprasylvian cortex and sparser connections from the lateral temporal and posterior parietal cortex. We made extensive physiological assessments of magnification factors in the extrastriate visual cortex and used these measures to convert the spread of labeled cortex in millimeters into a span in degrees of visual field. We also directly measured the visuotopic extents of receptive fields in the regions containing labeled cells in cases in which we made both CTb injections and physiological recordings in the same animals; we then compared the aggregate receptive field (ARF) of the labeled region in each extrastriate area with that of the injection site. In areas 18, 19, and 21, receptive fields of cells in regions containing labeled neurons overlapped those at the injection site but spanned a greater distance in visual space than the ARF of the injection site. The broad visuotopic extent of feedback connections is consistent with the suggestion that they contribute to response modulation by stimuli beyond the classical receptive field. (c) 2005 Wiley-Liss, Inc.