Discharge characteristics of pursuit neurons in MST during vergence eye movements
Discharge characteristics of pursuit neurons in MST during vergence eye movements
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DOI：
10.1152/jn.01028.2004
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发表时间：
2005-05-01
影响因子：
2.5
通讯作者：
Fukushima, K
中科院分区：
文献类型：
--
作者：
Akao, T;Mustari, MJ;Fukushima, K
对于在靠近观察者的空间中平滑移动的小物体，平滑的追踪和聚散眼球运动将目标图像保持在中央凹附近，以确保对关于移动物体的视觉信号的高分辨率处理。这两个系统的信号必须进行合成，以进行三维（3D）追踪。最近的研究表明，大多数的追求神经元在额眼场（FEF）的代码追求在三维的反应。该区域与内侧上级颞区（MST）有相互联系，而内侧上颞区（MST）是发现额叶追踪神经元的地方。为了研究追踪3D信号是否已经存在于MST中以及MST神经元在由小斑点引起的聚散追踪过程中如何放电，我们检测了2只猴子的MST追踪神经元的放电。在正面追踪和边缘追踪过程中共检查了219个追踪神经元，其中61%仅为正面追踪放电，18%仅为边缘追踪放电，21%为两者都放电。大多数与聚散相关的MST神经元对聚散眼速度表现出敏感性。他们的放电维持在短暂的空白的聚散目标。约1/3的聚散相关的MST神经元表现出对深度上的斑点运动的视觉反应。在我们的一半人群中，视觉运动和趋同跟踪的首选方向是相似的。剩下的一些神经元表现出相反的偏好方向。一个显着的比例（29%）的趋同相关的神经元放电前的眼动与领先时间超过20毫秒。在本研究和以往的研究结果表明，FEF和MST追求神经元的放电特性的差异，这表明不同的角色，为两个追求在3D。
For small objects moving smoothly in space close to the observer, smooth pursuit and vergence eye movements maintain target images near the foveae to insure high-resolution processing of visual signals about moving objects. Signals for both systems must be synthesized for pursuit-in-three-dimensions (3D). Recent studies have shown that responses of the majority of pursuit neurons in the frontal eye fields (FEF) code pursuit-in-3D. This area is known to have reciprocal connections with the medial superior temporal area (MST) where frontal pursuit neurons are found. To examine whether pursuitin-3D signals are already present in MST and how MST neurons discharge during vergence-tracking induced by a small spot, we examined discharge of MST pursuit neurons in 2 monkeys. Of a total of 219 pursuit neurons examined during both frontal pursuit and vergence-tracking, 61% discharged only for frontal pursuit, 18% only for vergence-tracking, and 21% for both. A majority of vergence-related MST neurons exhibited sensitivity to vergence eye velocity. Their discharge was maintained during brief blanking of a vergence target. About 1/3 of vergence-related MST neurons exhibited visual responses to spot motion in depth. The preferred directions for visual motion and vergence-tracking were similar in half of our population. Some of the remaining neurons showed opposite preferred directions. A significant proportion (29%) of vergence-related neurons discharged before onset of eye movements with lead times longer than 20 ms. The results in this and previous studies indicate differences in discharge characteristics of FEF and MST pursuit neurons, suggesting different roles for the two in pursuit-in-3D.