Focal Gain Control of Thalamic Visual Receptive Fields by Layer 6 Corticothalamic Feedback.
Focal Gain Control of Thalamic Visual Receptive Fields by Layer 6 Corticothalamic Feedback.
复制标题
通过第 6 层皮质丘脑反馈对丘脑视觉感受野的焦点增益控制。
DOI：
10.1093/cercor/bhw376
复制
发表时间：
--
期刊：
影响因子：
3.7
通讯作者：
Sillito Adam M
中科院分区：
文献类型：
--
作者：
Wang Wei;Andolina Ian M;Lu Yiliang;Jones Helen E;Sillito Adam M
丘脑和初级视觉皮质（V1）之间的投射是一个关键的相互神经回路，将视网膜信号传递到皮质第4和第6层，同时受到大量第6层皮质丘脑反馈的调节。有效地解剖这种皮质丘脑反馈回路在高等哺乳动物中的影响仍然是视觉研究的一个挑战。通过控制视觉驱动的猫V1的第6层反应的焦点增益，我们研究了这种焦点皮层变化对单个背外侧膝状体核（dLGN）细胞感受野（RF）的反应幅度和空间结构的影响。我们发现，增强视觉驱动的皮层反馈可以促进或抑制dLGN细胞的整体反应，这种效果与皮层神经元的取向偏好有关。与这些选择性视网膜增益变化相关，增强的反馈诱导dLGN细胞的RF扩大，收缩或转移其空间焦点。我们的研究结果提供了进一步的证据，通过这种功能机制，大脑皮层可以选择性地门视觉信息流从丘脑回到视觉皮层。
The projections between the thalamus and primary visual cortex (V1) are a key reciprocal neural circuit, relaying retinal signals to cortical layers 4 & 6 while being simultaneously regulated by massive layer 6 corticothalamic feedback. Effectively dissecting the influence of this corticothalamic feedback circuit in higher mammals remains a challenge for vision research. By pharmacologically increasing the focal gain of visually driven layer 6 responses of cat V1 in a controlled fashion, we examined the effects of such focal cortical changes on the response amplitudes and spatial structure of the receptive fields (RFs) of individual dorsal lateral geniculate nucleus (dLGN) cells. We found that enhancing visually driven cortical feedback could facilitate or suppress the overall responses of dLGN cells, and such an effect was linked to the orientation preference of the cortical neuron. Related to these selective retinotopic gain changes, enhanced feedback induced the RFs of dLGN cells to expand, contract or shift their spatial focus. Our results provide further evidence for a functional mechanism through which the cortex can selectively gate visual information flow from the thalamus back to the visual cortex.