Importance of NMDA receptors for multimodal integration in the deep layers of the cat superior colliculus
Importance of NMDA receptors for multimodal integration in the deep layers of the cat superior colliculus
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DOI：
10.1152/jn.1996.75.2.920
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发表时间：
1996-02-01
影响因子：
2.5
通讯作者：
Salt, TE
中科院分区：
文献类型：
--
作者：
Binns, KE;Salt, TE
1.许多感觉事件包含多通道信息，但大多数感觉核团都致力于单通道信息的分析。在深上丘(DSC)，视觉、听觉和躯体感觉信息汇聚在单个多模式神经元上。多通道神经元的反应是由汇聚输入的时间和空间对应特性决定的，因此，来自同一事件的刺激引起促进的多通道反应。N-甲基-D-天冬氨酸(NMDA)受体可能是检测空间和时间重合的基础，并可能参与多模式易化反应的产生，因为NMDA受体介导的事件具有非线性特性。为了评估NMDA受体在多模式整合中的作用，我们对猫DSC中的单个多感觉神经元进行了细胞外记录。用离子电泳法应用NMDA受体拮抗剂D-2-氨基-5-磷酸戊酸(AP5)激发对视觉、听觉和躯体感觉刺激以及多模式刺激组合的反应。对单独呈现的视觉刺激的所有反应(n=9)均显著降低。躯体感觉反应(n=25)通常降低。相反，对听觉刺激的反应减弱(n=9)、无影响(n=3)或增强(n=5)。无论构成刺激的模式是什么，在AP5离子导入期间，对多模式刺激呈现的反应持续减少。多通道反应的减幅显著大于对单通道刺激反应减幅的总和。这些数据表明，对于单峰刺激，NMDA受体在DSC感觉反应突触传递中的重要性可能依赖于刺激方式。此外，NMDA受体在整合来自不同模式的信息以产生多模式反应方面具有重要作用。
1. Many sensory events contain multimodal information, yet most sensory nuclei are devoted to the analysis of single-modality information. In the deep superior colliculus (DSC), visual, auditory, and somatosensory information converges on individual multimodal neurons. The responses of multimodal neurons are determined by the temporal and spatial correspondence properties of the converging inputs such that stimuli arising from the same event elicit a facilitated multimodal response.2. N-methyl-D-aspartate (NMDA) receptors may underlie the detection of spatial and temporal coincidence and could be involved in the generation of multimodal facilitatory responses because of the nonlinear properties of NMDA-receptor-mediated events. To assess the role of NMDA receptors in multimodal integration, we made extracellular recordings from single multisensory neurons in the DSC of the cat.3. The responses to visual, auditory, and somatosensory stimuli alone and to multimodal combinations of stimuli were challenged with iontophoretically applied D-2-amino-5-phosphonovalerate (AP5), an NMDA receptor antagonist. All responses to visual stimuli presented alone (n = 9) were greatly reduced. Somatosensory responses (n = 25) were usually decreased. In contrast, the responses to auditory stimulation were decreased (n = 9), unaffected (n = 3), or enhanced (n = 5).4. Responses to multimodal stimulus presentations were consistently reduced during iontophoretic application of AP5, irrespective of the modalities that made up the stimulus. The reductions of multimodal responses were significantly greater than the sum of the reductions of responses to single-modality stimuli.5. The data suggest that for unimodal stimuli, the importance of NMDA receptors in synaptic transmission of sensory responses in DSC may be dependent on the stimulus modality. Furthermore, NMDA receptors are of major importance in the integration of input from different modalities for the generation of multimodal responses.