A theory of the dual pathways for smooth pursuit based on dynamic gain control
A theory of the dual pathways for smooth pursuit based on dynamic gain control
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DOI：
10.1152/jn.90237.2008
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发表时间：
2008-06-01
影响因子：
2.5
通讯作者：
Glasauer, Stefan
中科院分区：
文献类型：
--
作者：
Nuding, Ulrich;Ono, Seiji;Glasauer, Stefan
平滑追踪眼动（SPEM）系统在追踪期间比在注视期间对目标运动扰动更敏感。这种灵敏度通常归因于动态增益控制机制。这种增益控制的神经基质和功能结构都还没有完全揭示。至少有两个皮质区域对平滑追踪起着至关重要的作用，因此是动态增益控制的合格部位：内侧上级颞区（MST）和额叶眼野（FEF）的追踪区，它们都通过平行通路投射到脑干运动前区结构。本研究的目的是开发一个模型的基础上的行为，解剖学和神经生理学的结果，考虑到非线性动态增益控制的平滑追求。使用由叠加在恒定速度目标运动（0-24度/s）上的正弦振荡（4 Hz，+/-8度/s）组成的人类行为范例，我们能够识别模型中的相关增益控制参数。我们的模型的一个显着特点是出现了两个平行的通路从较高的视觉皮层到较低的运动区在脑干中，对应于MST和FEF途径。对模型的详细分析表明，一条通路主要携带眼速相关信号，而另一条通路主要与眼加速度相关。从与已知的神经生理学结果的比较，我们得出结论，动态增益控制可以归因于FEF通路，而MST通路作为维持持续SPEM的基本电路。
The smooth pursuit eye movement (SPEM) system is much more sensitive to target motion perturbations during pursuit than during fixation. This sensitivity is commonly attributed to a dynamic gain control mechanism. Neither the neural substrate nor the functional architecture for this gain control has been fully revealed. There are at least two cortical areas that crucially contribute to smooth pursuit and are therefore eligible sites for dynamic gain control: the medial superior temporal area (MST) and the pursuit area of the frontal eye fields (FEFs), which both project to brain stem premotor structures via parallel pathways. The aim of this study was to develop a model of smooth pursuit based on behavioral, anatomical, and neurophysiological results to account for nonlinear dynamic gain control. Using a behavioral paradigm in humans consisting of a sinusoidal oscillation (4 Hz, +/- 8 degrees/s) superimposed on a constant velocity target motion (0-24 degrees/s), we were able to identify relevant gain control parameters in the model. A salient feature of our model is the emergence of two parallel pathways from higher visual cortical to lower motor areas in the brain stem that correspond to the MST and FEF pathways. Detailed analysis of the model revealed that one pathway mainly carries eye velocity related signals, whereas the other is associated mostly with eye acceleration. From comparison with known neurophysiological results we conclude that the dynamic gain control can be attributed to the FEF pathway, whereas the MST pathway serves as the basic circuit for maintaining an ongoing SPEM.