Roles of caudal frontal eye fields (FEF) in representation of visual information in space : Comparison with MT/MST.

最近的研究表明，额眼区（FEF）的尾部含有平滑追踪神经元。FEF与皮层MT和MST之间存在着相互联系。为了了解FEF在空间视觉信息和追求眼球运动的表征中的作用，我研究了FEF追求神经元是否也对聚散眼球运动做出反应，并将它们的活性与MT/MST中的活性进行了比较。头部固定的日本猴子被训练去追踪一个在正面和深度上移动的点。在额叶追踪和聚散两个过程中，我测试了FEF中的155个神经元和MT/MST中的143个神经元。E.深度追踪）。大多数FEF神经元（66%）调制强烈，在额叶和深度追求，导致三维（3D）笛卡尔表示的眼球运动。虽然MT/MST包含的神经元，在正面和深度追求的反应，这样的神经元的百分比（12%）相比，在FEF少得多。大多数MT/MST神经元仅在额叶追踪时有反应（76%对26%）。当动物注视静止点时，比较虚拟点或光流的正弦运动的视觉反应。大多数（33/61）的FEF神经元测试响应点运动和流量在额平面和/或深度与视觉偏好的方向类似的追求。相比之下，大多数MT/MST神经元（57/106）测试响应的光流和点运动的首选方向相反，在追求。FEF和MT/MST中神经元之间的这些差异表明两个皮层区域在追踪中的不同作用，并支持3D追踪信号主要在FEF中合成的观点。

Recent studies show that caudal parts of the frontal eye fields(FEF)contain smooth pursuit neurons. FEF has reciprocal connections with the cortical MT and MST. To understand the FEF role in representation of visual information and pursuit eye movements in space, I examined whether FEF pursuit neurons also respond to vergence eye movements and compared their activity with that in MT/MST. Head-fixed Japanese monkeys were trained to pursue a spot that moved in frontal planes and depth. I tested 155 neurons in FEF and 143 neurons in MT/MST during both frontal pursuit and vergence(I. E. depth pursuit). Majority of FEF neurons(66%)modulated strongly during both frontal and depth pursuit, resulting in three dimensional(3D) Cartesian representation of eye movements. Although MT/MST contained neurons that responded during both frontal and depth pursuit, the percentage of such neurons was much less(12%)compared to that in FEF. Majority of MT/MST neurons responded only during frontal pursuit(76% vs 26% in FEF). Visual response to sinusoidal motion of a virtual spot or optic flow was compared while the animals fixated a stationary spot. Majority of FEF neurons tested(33/61)responded to spot motion and flow in frontal plane and/or depth with visual preferred directions similar to those during pursuit. In contrast, majority of MT/MST neurons tested(57/106)responded to optic flow and spot motion with preferred directions opposite to those during pursuit. These differences between neurons in FEF and MT/MST suggest different roles for the two cortical areas in pursuit and support the view that 3D pursuit signals are synthesized mainly in FEF.