Complex Effects on In Vivo Visual Responses by Specific Projections from Mouse Cortical Layer 6 to Dorsal Lateral Geniculate Nucleus
Complex Effects on In Vivo Visual Responses by Specific Projections from Mouse Cortical Layer 6 to Dorsal Lateral Geniculate Nucleus
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DOI：
10.1523/jneurosci.0027-15.2015
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发表时间：
2015-06-24
影响因子：
5.3
通讯作者：
Contreras, Diego
中科院分区：
文献类型：
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作者：
Denman, Daniel J.;Contreras, Diego
理解丘脑皮质投射在形成丘脑视觉反应特性中的作用一直是视觉神经科学领域的一个长期挑战。在这里，我们利用转基因小鼠细胞系GN220-Ntsr1 Cre细胞系的细胞类型特异性，选择性地操纵第6层（L6）膝状皮质细胞群的活性，同时记录背外侧膝状核（dLGN）的视觉反应。虽然驱动Ntsr1投射输入导致dLGN神经元的诱发尖峰计数可靠地减少，但去除这些相同的投射会导致视觉诱发尖峰计数的增加和减少。增加和减少都依赖于对比度，并且符号在整个对比度范围内是一致的。调谐特性表明具有相似时空频率调谐的Ntsr1细胞广泛收敛到单个dLGN细胞上，我们没有发现Ntsr1细胞增强时空滤波的证据。这些非特异性变化独立于突发频率的变化而发生，表明Ntsr1促皮质酸活性可导致净兴奋和净抑制。
Understanding the role of corticothalamic projections in shaping visual response properties in the thalamus has been a longstanding challenge in visual neuroscience. Here, we take advantage of the cell-type specificity of a transgenic mouse line, the GN220-Ntsr1 Cre line, to manipulate selectively the activity of a layer 6 (L6) corticogeniculate population while recording visual responses in the dorsal lateral geniculate nucleus (dLGN). Although driving Ntsr1 projection input resulted in reliable reduction in evoked spike count of dLGN neurons, removing these same projections resulted in both increases and decreases in visually evoked spike count. Both increases and decreases are contrast dependent and the sign is consistent over the full range of contrasts. Tuning properties suggest wide convergence of Ntsr1 cells with similar spatial and temporal frequency tuning onto single dLGN cells and we did not find evidence that Ntsr1 cells sharpen spatiotemporal filtering. These nonspecific changes occur independently of changes in burst frequency, indicating that Ntsr1 corticogeniculate activity can result in both net excitation and net inhibition.