Different glutamate receptors convey feedforward and recurrent processing in macaque V1
Different glutamate receptors convey feedforward and recurrent processing in macaque V1
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DOI：
10.1073/pnas.1119527109
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发表时间：
2012-07-03
影响因子：
11.1
通讯作者：
Roelfsema, Pieter R.
中科院分区：
文献类型：
--
作者：
Self, Matthew W.;Kooijmans, Roxana N.;Roelfsema, Pieter R.
初级视觉皮层（V1）的神经元接收来自丘脑的前馈输入，丘脑形成感受场特性。此外，它们还通过V1内的水平连接接收周期性输入，以及来自高级视觉区域的反馈，这些视觉区域被认为对有意识的视觉感知很重要。在这里，我们研究了不同的谷氨酸受体在猕猴V1中传递前馈和经常性输入中扮演的角色。作为一个衡量递归处理，我们使用图形-背景调制（FGM），增加的活动，代表数字的神经元相比，背景，这取决于来自更高的区域的反馈。我们发现，前馈驱动的活动强烈减少AMPA受体拮抗剂6-氰基-7-硝基喹喔啉-2，3-二酮（CNQX），而这种药物对FGM没有影响。相反，NMDA受体阻滞剂减少FGM，而它们对视觉驱动活动的影响随药物的亚基特异性而变化。NMDA受体阻滞剂2-氨基-5-膦酰基戊酸酯（APV）导致视觉反应轻微降低，而艾芬地尔（其靶向含有NMDA受体NR 2B亚基的NMDA受体）增加视觉反应。这些研究结果表明，谷氨酸受体有助于不同的前馈和经常性的处理在V1和建议的方法来选择性地破坏经常性的处理，使其在视觉感知的作用可以阐明。
Neurons in the primary visual cortex (V1) receive feedforward input from the thalamus, which shapes receptive-field properties. They additionally receive recurrent inputs via horizontal connections within V1 and feedback from higher visual areas that are thought to be important for conscious visual perception. Here, we investigated what roles different glutamate receptors play in conveying feedforward and recurrent inputs in macaque V1. As a measure of recurrent processing, we used figure-ground modulation (FGM), the increased activity of neurons representing figures compared with background, which depends on feedback from higher areas. We found that feedforward-driven activity was strongly reduced by the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), whereas this drug had no effect on FGM. In contrast, blockers of the NMDA receptor reduced FGM, whereas their effect on visually driven activity varied with the subunit specificity of the drug. The NMDA receptor blocker 2-amino-5-phosphonovalerate (APV) caused a slight reduction of the visual response, whereas ifenprodil, which targets NMDA receptors containing the NMDA receptor NR2B subunit, increased the visual response. These findings demonstrate that glutamate receptors contribute differently to feedforward and recurrent processing in V1 and suggest ways to selectively disrupt recurrent processing so that its role in visual perception can be elucidated.