A Model of Partial Reference Frame Transforms Through Pooling of Gain-Modulated Responses
A Model of Partial Reference Frame Transforms Through Pooling of Gain-Modulated Responses
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DOI：
10.1093/cercor/bhs117
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发表时间：
2013-05-01
期刊：
影响因子：
3.7
通讯作者：
Spratling, Michael W.
中科院分区：
文献类型：
--
作者：
De Meyer, Kris;Spratling, Michael W.
在后顶叶皮质(PPC)的多模式整合和感觉运动转换区，神经反应经常出现在位于固有感觉参照系中间的空间参照系中，例如，视觉以眼睛为中心，听觉刺激以头部为中心。这些区域的许多感觉反应也受到凝视方向的调节。我们证明，某些类型的混合帧反应可以通过汇集增益调制的反应来产生，类似于视觉皮质中的复杂细胞被认为汇集简单细胞的反应。所提出的模型模拟了在PPC中观察到的两种类型的混合帧反应：具体地说，随着凝视在水平和垂直维度上的差异移动的感觉反应，以及沿着凝视的单一维度对不同起始点和终止点的不同移位的感觉反应。我们将这两种类型的混合框架反应与第三种类型区分开来，在第三种类型中，感觉反应随着每一次凝视移动而移动部分但大致相等的量。我们认为，关于混合框架反应的经验数据可能是由多种机制造成的，我们调整了现有的参考框架措施来区分不同的类型。最后，我们讨论了混合框架反应如何揭示突触前反应的局部组织。
In multimodal integration and sensorimotor transformation areas of the posterior parietal cortex (PPC), neural responses often appear encoded in spatial reference frames that are intermediate to the intrinsic sensory reference frames, for example, eye-centered for visual or head-centered for auditory stimulation. Many sensory responses in these areas are also modulated by direction of gaze. We demonstrate that certain types of mixed-frame responses can be generated by pooling gain-modulated responses similar to how complex cells in the visual cortex are thought to pool the responses of simple cells. The proposed model simulates 2 types of mixed-frame responses observed in the PPC: in particular, sensory responses that shift differentially with gaze in horizontal and vertical dimensions and sensory responses that shift differentially for different start and end points along a single dimension of gaze. We distinguish these 2 types of mixed-frame responses from a third type in which sensory responses shift a partial yet approximately equal amount with each gaze shift. We argue that the empirical data on mixed-frame responses may be caused by multiple mechanisms, and we adapt existing reference-frame measures to distinguish between the different types. Finally, we discuss how mixed-frame responses may be revealing of the local organization of presynaptic responses.